The Bulletin of the Museum of Natural History of the University of Oregon is published to increase the knowledge and understanding of the Natural History of Oregon. Original articles in the fields of Archaeology, Botany, Ethnology, Geology, Paleontology and Zoology appear ir- regularly in consecutively numbered issues. Contributions arise primarily from the research programs and collections of the Museum of Natural History and the Oregon State Museum of Anthropology. However, in keeping with the basic purpose of the publication, contributions are not restricted to these sources and are both technical and popular in character. J. ARNOLD SHOTWELL, Director Museum of Natural History University of Oregon Communications concerning manuscripts and purchase of copies of the Bulletin should be addressed in care of the Museum of Natural History, University of Oregon, Eugene, Oregon 97403. A list of previous issues of the Bulletin will be found inside the back cover. MIOCENE MAMMALS OF SOUTHEAST OREGON MIOCENE MAMMALS OF SOUTHEAST OREGON by J. ARNOLD SHOTWELL Bulletin No. 14 Museum of Natural History University of Oregon Eugene, Oregon August 1968 Funds for publication of Bulletin No. 14 provided by the National Science Foundation grant GB 3971. 1 MIOCENE MAMMALS OF SOUTHEAST OREGON by J. ARNOLD SHOTWELL Museum of Natural History University of Oregon INTRODUCTION The late Miocene fauna described here rep- resents the earliest step in a sequence of late Tertiary faunas studied as a part of a long range investigation into the interrelationships of the factors of faunal change. The study is deliberately provincial to reduce biogeograph- ic effects and to allow independent time con- trols to be developed through detailed geologic mappmg. The concept of the bulk fauna is used to indicate the entire fauna of the Northern Great Basin at any particular time. The association or community is the basic unit of study, the bulk fauna is the whole of which the associa- tions are the overlapping parts. The recognition and description of associa- tions are dependent on quantitative data. Thus excavation must be carried out in such a way that useful quantitative information is re- trieved. Previous studies of late Miocene, Bar- stovian, occurrences in the immediate area of study, Skull Spring ( Gazin 1932), Sucker Creek ( Scharf 1935) , and in nearby areas, Virgin Valley ( Merriam 1911), Beatty Butte (Wallace 1946) , Mascall ( Downs 1956) , were based on float materials and limited excava- tions, lumped together as faunas. These studies provide material and conclusions useful in the taxonomic assignment of species occurring in samples hut do not contribute quantitative data nor do they reflect the environmental diversity apparently present. This report is based on excavations made to provide the type of data required for paleo- ecological study. The large amount of new ma- terial recovered, particularly small mammals, has involved more taxonomic work than was originally anticipated. The occurrence and systematics are thus presented here as a sepa- rate report as will also be the case with the Pliocene faunas, which make up the remainder of the sequence. The paleoecological consider- ations of the entire sequence, Barstovian to Blancan, will form a final report. The insec- tivores from both the Miocene and Pliocene faunas were studied by J. H. Hutchison and are separately reported on by him ( 1966, 1968). Shotwell (1967 A & B) has previously de- scribed the cricetine and geomyoid rodents from these localities. The geology has been studied by L. R. Kittleman and associates. The stratigraphy( Kittleman et al., 1965) and geo- logic map (Kittleman et al., 1967) are pub- lished separately. ACKNOWLEDGMENTS The material which forms the basis of this report was collected in the summers of 1960 and 1961. Over thirty persons were involved in the success of these two seasons and I wish to acknowledge their contributions. Our 1960 camp was located at the old Ralph Page ranch northwest of Quartz Mountain. Mr. Page had developed a spring and stock pond which were important considerations in locat- ing the camp. The ranch is about midway be- tween two local fossiliferous areas which we investigated. Jean Morcom, who was the cur- rent owner of the property, made it available to us. Stewart Elsinore of Big Mud Flat ranch 6 miles to the south loaned a horse and gave 2 ... 450 440 430 ... BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON 120" Paulina • i i jJ i i i I 120" i !Butte !. I i i 119° 119° ue0 117° 0 5 10 20 30 MILES ,, .. 117° No.14 450 400 440 43° . .. 1968 SHOTWELL: MIOCENE MAMMALS 3 other assistance. The crew was made up as fol- lows: Excavation crew, Richard Wilson, Jon Jacklet, Fred Crafts, Fred Cole, Jim Haight, Garry Millhollen and Gene Winters; Geolo- gists, L. R. Kittleman, Robert "Pete" Russell and Arvid Johnson; Cook, Lillian Wells; Cook's helper, Charlene Wells. The 1961 camp was located at "Millers Cow Camp" on Dry Creek, the former site of Little- field. Julian Arian of Juntura made the line shack there available to us. A very good spring is also present. Drex Williams, also of Jun- tura, made facilities available for the geolo- gists both during the 1961 season and 1962. Bud Rogers put up our spring recon crew for several days when we were caught in a late snowstorm. The crew consisted of, geologists L. R. Kittleman, Art Green, Jay McMurray, and Allen Hagood; excavation crew, Richard Wilson, Stuart Shininger, Loren Cox, Don Lan- denberger, Gary Kessler, Allan Heinricks, Gary Shaeffer and Gary Millhollen; Lillian Wells was cook and Charlene Wells her helper. The Laboratory work was completed by Richard Wilson, Jon J acklet, Stuart Shininger, George Howe and Janet Mack. The illustra- tions in this report are by Mildred Detling with the exception of figure 10 which was prepared by Pamela Parsons. The photography is by Bernard Freemesser of the University of Ore- gon photo bureau, Richard Wilson and Fred Crafts. The field and laboratory work was primarily supported by NSF grant G 10684 ( environ- mental biology). Four students were supported in each of the two field seasons under the NSF, URP program, grants G 12023 and 15861. NSF grant G 21820 ( facilities and special pro- grams) provided new facilities and resources which aided in the study of the materials and in subsequent field work. NSF grant GB 3971 ( environmental biology) provided funds for the analysis and publication of the results of the entire previous program. To these individ- uals and the National Science Foundation I am deeply indebted. Figure 1. General location map. OCCURRENCES Previously known Barstovian collections from the Northern Great Basin are all very similar, representing possibly two associations; one which might be termed the Merychippus- Dromomeryx association and the other, usually more poorly represented, the Hypohippus- Ticholeptus association. None of the expected members of a pond-bank association, so com- mon in the Pliocene, were known such as beav- ers, Peromyscus, turtles, fish, etc. The Paleo- botanical evidence indicated, however, that such an association could be expected. The problem then was not only to find suitable sites for the excavation of quantitatively useful sam- ples of those associations which were obviously present, but to also find samples of other asso- ciations which were expected and to find them within the geographic limitations imposed. Together a number of the known Barstovian localities, including Skull Springs and Beatty Buttes and many other less well known sites, form a large contiguous area in southeastern, south central Oregon and northern Nevada. Within this large area no post-Barstovian sedi- ments occur although post-Barstovian igneous rocks are present. Younger sediments are en- countered in numerous localities peripheral to this area but lower topographically. This line of evidence led to a working hypotheses that the topographically higher area of thin Bar- stovian sediments had been continually high since the Barstovian and that the peripheral younger sediments represented the location of a number of small, and some rather large basins. Typically when descending into these basins from the "Barstovian high" Hemphillian sediments were first encountered in contact with those of Barstovian age. If the basin had been deeply cut, Clarendonian sediments were seen and finally Barstovian again but of dif- ferent lithology than those on the high. In some of these basins still earlier rocks were present. The Barstovian sediments in the basins on the west and southwest side of the "high" had been carefully examined. This was disappointing in that they commonly consist of diatomite and 4 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 Figure 2. North end of Qu.artz Basin. very fine ash. Very few vertebrates were to be seen in them, however, plant fossils were fre- quently present. The same failure had occurred on the north side of the Barstovian high in the J untura Basin ( see Shotwell 1963) . To the east, in Malheur County it was believed that an ex- tensive series of Barstovian sediments were present, however, the area was virtually un- known and relatively inaccessible. On the east and south it is bounded by the 1000 ft. deep Owyhee gorge occupied by a reservoir. On the north it is nearly isolated by a deep east-west branch canyon occupied by Dry Creek. On the west the distance from any sort of all-weather road had discouraged previous investigations. Study of air-photos of the area showed the sedi- ments to be apparently fine grained but prob- ably not diatomites. This then seemed to be the mostly likely area in which we might expect to find the associations of mammals we felt were missing and would be expected to be best developed in a lowland environment. In the spring of 1960 two attempts were made to reconoiter the area. The first one aborted due to a sudden thaw of a heavy snowfall and a fire in our vehicle. The second one was suc- cessful in that we reached the area and found evidence that a Barstovian stream-bank asso- ciation was present and apparently abundantly represented. This was in the northern end of Quartz Basin. In the summer of 1960 a base camp was established a few miles to the west at the then unoccupied Page Ranch. From the Page Ranch camp three geologists mapped the surrounding area, while the author and seven students made test excavations in Quartz Basin to the east and Juniper Creek Canyon to the west. Quartz Basin is an erosional feature exca- vated in the lower members of the Deer Butte formation. The south and east borders of the basin are composed of low hills of the Red Butte and Orlando Springs Members while the west and northern borders consist of the some- 1968 SHOTWELL: MIOCENE MAMMALS 5 Figure 3. 1961 camp at Millers Cow Camp. what higher hills of the Holdout and Quartz Mountain Members. The basin is shallow and drains into the Owyhee River to the south and the Owyhee Reservoir to the east over a thou- sand feet lower topographically. Vegetation in the basin is sparse and consists primarily of grasses with low brush around the borders of the basin and along drainage courses. There are no permanent streams in the basin although a year round spring, Ferguson Spring, flows at its northwest edge. The floor of the basin is between 3700-3800 feet in elevation with the surrounding hills at 4000 feet. Quartz Moun- tain rises from the west side of the basin to a height of over 5100 feet. Fossils were collected from the Holdout Member of the Deer Butte Formation at six- teen localities along the northwest border of Quartz Basin. The Holdout Member is overlain by the Quartz Mountain Member. One of these localities, UOloc 2465, was developed into a quarry which produced a quantitative sample from a productive level less than a foot thick. Some faunal elements were recovered from the other localities which did not occur in the quarry. These are described in order to pro- vide a more complete faunal list although they will not appear in the eventual quantitative analysis which is restricted to UOloc 2465. The productive level of the Quartz Basin lo- cality was completely removed, sacked and hauled about 8 miles to the Page Ranch where it was alternately soaked in the stock pond and dried in the sun using screens of 14 x 18 mesh. The concentrate from this screening was hauled to the museum where the bone was segregated from the remaining matrix. A little over three tons of productive level was so worked using 80 screens. An additional small sample was taken from the east end of the quarry in the fall of 1965 and submited to the kerosene treatment ( see Wilson 1965) and 24 mesh screen in order to derive an estimate of the difference in results 6 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No. 14 Figure 4. Localily UO/,oc 2465 Quartz Basin. Figure 5. Localily UO/,oc 2495 Red Basin. 1968 SHOTWELL: MIOCENE MAMMALS 7 Figure 6. Washing matrix from Quartz Basin locality. which might be expected due to the variation in this recovery technique which had been ap- plied in subsequent excavations. Float material is abundant in a number of localities in the vicinity of Skull Springs and in Red Basin. The description of the Skull Springs Fauna (Gazin 1932) is based on such material from Red Basin indicating that a rather complete faunal list, at least of the larger mammals, may be obtained in this way. How- ever, such material presents serious handicaps to any quantitative analysis other than very crude estimates. To acquire quantitatively use- ful samples searches for possible excavation sites in this area were made during the course of seven field seasons. These efforts were for · short periods of time but produced little in the way of encouragement. Assuming that a con- certed effort over a longer single period of time would be successful, a large camp was estab- lished at Miller's Cow Camp on Dry Creek in the summer of 1961. A number of productive areas, north, east, and south of this point were examined. Eventually a dry wash in the north- ern half of Red Basin was examined in which large amounts of fragmental and complete vertebrate skeletal elements were found, UOloc 2493. Preliminary excavation produced speci- mens in place but also indicated that much of the concentration was already gone probably represented by the float as a lag deposit from the sediment removed by the dry wash. To test this conclusion another excavation was started just to the east and above the dry wash in the thin soil (UOloc 2495). Weathered specimens were soon encountered in the soil horizon and once unweathered sediment was reached a con- siderable amount of material was obviously present. Sagebrush was then cleared away and excavation started on the site. Screening of the well consolidated matrix was attempted using wetting and drying but was completely unsuc- cessful. Excavation was carried out by remov- ing blocks of sediment whenever specimens 43 14 5 R E D B A SI N M IL LE R' ' • 24 95 /., ,,. • 24 1) ,7/ • 24 ()] I / I I I t:l \ SK U LL SP R II 'G S 43 13 0 ;? I I I . . , / / / / / / \ / I / ' · ~ I ( ' ' ' \ I / / I / I I I I I I J I I I 0 " ... . . . . \ ' ' - - - - , A nt el op e F la t \ ' \ \ 11 7 '4 5 Fi gu re 8 . Lo ca lit y m a p. ' " I ) /'\ I • 24 ~(1 I \ _ . . . , \ / ~ ,. . ,, ,. ., .. ._ , \. I I I I I I I I I lo x h ow \ B as in \ • 24 31 \. ) q {) Q p ~ 1 ·· ~ 5 3 & ' ~ ,, .. .. .. / I .L a> 'A GE R A N C' °h / · 24 65 '- Q U l\& flT Z / (\ 24 • 24 56 B A ~I N \? 24 6 • \ J . 24 57 -8 , I • 24 61 j / I I / ll 7' 30 . . . . 0 0: , ~ ~ '""l ~~ Si: ~ ~ ~ ~ '""l ~ ;::,;:, ::i... t-, ~ V) '""l ~ ~"<: ~ ;; ;::,;:, ~ '""l "<: 0 "'>j ~ t,j ~ ~ 2 ~ .... if>. 1968 SHOTWELL: MIOCENE MAMMALS 11 the contact is in an area of about 1000 ft of relief and very difficult to reach and work in. Apparently at no point is the relationship of the Littlefield Rhyolite and the Deer Butte For- mation unquestionable. The Quartz Mountain Member of the Deer Butte appears to, at least in part, overlie the Littlefield Rhyolite but may actually interfinger with it. Thus the Butte Creek Volcanic Sandstone containing the Red Basin faunule and the Deer Butte Formation with the included Quartz Basin faunule appear to occupy similar stratigraphic positions. A previously described fauna, the Sucker Creek fauna (Scharf 1935), is not involved di- rectly in the present report but is significant in any discussion of faunas of this region. This fauna occurs in the Sucker Creek Formation ( see Kittleman et al. , 1965). Both the Sucker Creek Formation and the Deer Butte Formation are in the Owyhee "trough." Their stratigraph- ic relationships are, however, complex. The Deer Butte Formation overlies the Owyhee Ba- salt in its northern and eastern extent. The Owy- hee Basalt overlies a rhyolite at Owyhee Dam which in its southeastward extent appears to overlie the Sucker Creek Formation. Upper members of the Deer Butte Formation unques- tionably overlie the Sucker Creek Formation to the northeast and the lower members overlie the Leslie Gulch Ash-Flow Tuff, a member high in the Sucker Creek Formation, to the south. The field evidence thus indicates that all of the Deer Butte Formation lies stratigraphically above the Sucker Creek Formation (see Kittle- man et al., 1965, 1967). The physical geology of the region thus indi- cates that the Red Basin and Quartz Basin lo- calities occur at about the same stratigraphic level whereas the Sucker Creek localities ap- pear much lower in the local section. FAUNAL RELATIONSHIPS Thirty six species of mammals were col- lected in Red Basin of which thirty three were found in the main quarry, UOloc 2495. Twenty two species were previously known from Red Basin as the Skull Springs fauna (Gazin 1932, Hall 1931, Bode 1934, Downs 1956). Five of the previously recorded species were not rec- ognized in our collections; four carnivores, Pliocyon, Euoplocyon, Hemicyon, and Tomic- tus and a chalicothere. The total known Skull Springs fauna thus includes forty two species. About one half of these are insectivores or ro- dents. Fourteen species collected in Red Basin were previously unknown in the Northern Great Basin. Quartz Basin localities produced thirty four species of mammals, of which thirty one were recovered from the main quarry UOloc 2465. Seventeen species occurring in Quartz Basin were previously unknown in the Northern Great Basin. The Quartz Basin localities were deliberate- ly established to reveal an aspect of the North- ern Great Basin fauna previously unknown but TABLE 1 SPECIES PREVIOUSLY UNKNOWN IN THE NORTHERN GREAT BASIN Order Red Basin Marsupalia. .. ... .......... ............. .. .... ....... .. .... ...... .......... . ... 0 lnsectivora. .. .. ..... ... . .. .. .. .... .................... ............... ..... .... 9 Lagomorpha....... .. ............. .... ......... ... .. .. .... .. .... .............. 0 Rodentia. ........ ....... ... ..................... ...... .... .. .. .... ....... ... .... 5 Carnivora........ .. .. .. .. .. ...... ..... ........ .. .... .. ............ .... .. ..... .. 0 Proboscidea.. ... . .... ...... ... ....... . .. ...... .... ....... ........... ....... .. 0 Perissodactyla............................................ .......... .. .. .. ... 0 Artiodactyla.......... ..... ................... ..... ...... .. ........ ...... ..... 0 Total. ..... ....... ...... ............. ..... ....... ...... ...... ..... .... ..... 14 Quartz Basin Both 1 0 9 3 0 0 6 2 1 0 0 0 0 0 0 0 17 5 Total 1 14 0 9 1 0 0 0 25 12 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON TABLE 2 Red Basin Red Basin Red Basin Species All Sites 2495 2497 Marsupalia Didelphid sp ...... ..... .... ..... ........ ............. ........ . lnsectivora Erinaceidae incertae sedis ........................... . Lantarwtherium sp ........................................ X x Meterix cf. latidens ....................................... X x Mystipterus pacificus ..................... ............... X x Scalopoides ripofodiator .............................. X x Domninoides sp ... _______ _______________________________ _ Scapanoscapter simpliculens ........................ X x Scalopina sp .................................................. X x Achlyoscapter longirostris .. ................ ......... . Talpidae incertae sedis ................................ . Paradomnina relictus ................................... X x H eterosorex sp ...................................... ...... .. X x Alluvisorex arcadentes .......... ......... ............... X x Ingentisorex tumidens ..... ........ .. ............... ... . Limnoecus sp ....... .. ......... .... .. ............ .... ......... X x Lagomorpha Hypolagus sp ................................................ . Rodentia Liodontia alexandrae .................................... X x Mylagaulus cf. laevis .................................... .X x x Protospermophilus malheurensis ................. X x Spermophilus tephrus ................................... X x Eutamias sp .............. ..... ...... .......................... X x Sciuropterus sp ............................................. X x M onosaulax typicus ...................................... X x M onosaulax progressus ...................... .......... . M onosaulax sp ... ........ ......... .............. ...... .... . . Adjidaumo quartzi ..... ... ...... .... ........... .... ...... . Pseudotheridomys pagei ...... ..................... ... . X x Peridiomys oregonensis ................ .. ... ........ ... X x Prodipodomys mascallensis ......................... . Peromyscus pagei ............. ....... .............. ....... X x Peromyscus sp ............... ..... .................. ........ . M acrognathomys sp .................... .. ... ......... ... . Carnivora T omarctus kelloggi ....................................... X x x Tomarctus rurestris ...................................... X x Canid sp ............... ........... ...... .......... .............. . Pliocyon sp .................................................... X Euoplocyon sp ............................................... X H emicyon sp .......................... ...... .................. X Amphicyon cf. frendens ................................ X x Martes gazini ................................................. X Mustella sp ........ .. ......................................... . Brachypsalis sp ............................................. X x Bassariscus sp .... ........ .. ...... ...... ..... .. ..... ........ . Pseudaelurus sp ....... ........... .............. ............ X x Quartz Basin All Sites x x x x x x x x x x x ?X x x x x x x x x x x ?X x x x Quartz Basin 2465 x x x x x x x x x x x ?X x x x x x x x x x x ?X x x x No.14 Sp. in Common x x x x ?X x x x ?X x 1968 SHOTWELL: MIOCENE MAMMALS 13 TABLE 2 (cont.) Red Basin Red Basin Red Basin Quartz Basin All Sites Quartz Basin 2465 Sp. in Common Species All Sites 2495 2497 Proboscidea Mastodont .. ... ... ............ ..... ....... ....... ............ .. . X Perissodactyla Hypohippus cf. osborni .. .... ... ...... .. ............. .. X Parahippus cf. avus ....... .. .......... ... ... ..... ........ X Merychippus seversus .. .... ........... ... ...... ..... .... X Merychippus relictus ...... .... .... .... ......... ....... .. . M erychippus brevidontus ... .......... ..... .... ... .... X Merychippus sp .... ....... .... ..... ...... .... ............ .. . Chalicotheridae .. ....... ...... .... .. ........................ X Aphelops sp ... ........... ..... .. ........ ... .. ............. .. .. X Artiodactyla Prosthennops sp .... ........ .. .... .... ...... ....... ..... .... X Ticholeptus obliquidens ............... .... ... ..... .... . X Camelid .............. .. ..... ............ .... .. .... ......... ... .. X Dromomeryx borealis .. ........ ... .. ............ ... ..... X Rakomeryx americanus ........... .... ... ...... ... ..... X Merycodus cf. nevadensis ... ....... ... .... .. ...... .. . . M erycodus sp ....... .... ... ...... ....... .. .. ......... ... ..... X M erycodus sp ....... ...... ..... ........ ..... .. ............. . . believed to be present. The representation of mammals is quite different between Quartz Basin and Red Basin. Of the total sixty three species known from the two areas only nine are positively recognized in both, four insecti- vores, three rodents, one carnivore and one ar- tiodactyl. Five others, are poorly represented. Generic assignment may be sound but species assignment is not reliable either at both basins or in one or the other. In numbers of specimens, large mammals are more abundant at Red Ba- sin and small mammals at Quartz Basin. How- ever, this apparently does not account for the low resemblance between the two faunas. Forty different species of small mammals are known in the two faunas, twenty at Red Basin and twenty one at Quartz Basin, but only eight species are common to both faunas ( see Table 3). Sciurimorph rodents are rare in the Quartz Basin fauna whereas six species of six genera are present at Red Basin. Seven species of six genera of myomorph rodents occur in Quartz Basin whereas only three are present at Red x x x x x x x x x x x ?X x x x x x x x x ?X ?X ?X x x ?X x ?X x x x x x x Basin, all are species found at Quartz Basin. ( see Table 4) Fifteen species of insectivores oc- cur in the two basins but only four are common to both areas. Each basin has nine species of insectivores represented. ( see Table 5) In general the carnivores of Quartz Basin are small and those of Red Basin large. Ungu- lates are represented by eight species at Quartz Basin. Three species are apparently present in both basins although two of these are ques- tionable. The large ungulates with their associated large carnivores of Red Basin are not common at Quartz Basin. Insectivores, rodents, small carnivores and the smaller ungulates are best represented. Three of the sixteen genera of mammals in common to Quartz Basin and Red Basin are represented by different species. Monosaulax, Merychippus and Merycodus. The species of two of these genera are well enough known to allow comparisons to be made which may be of value in better understanding the relation- 14 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON TABLE 3 RESEMBLANCE OF THE RED BASIN AND QUARTZ BASIN SAMPLES ALL MAMMALS No.14 Order Red Basin Quartz Basin Species in common Resemblance Marsupalia.... ........... ................ ...... .............. ....... .. . 0 1 0 lnsectivora .... ... ................... .................. ......... ... ..... 10 9 4 Lagomorpha. .... . ..... .. ......... ...... ............. .... .. .. ....... .. 0 1 0 Rodentia ............... .. ..... ....... .......... ...... ..... .... ......... .. 10 10 4 Carnivora....... . ....... .... ............ ............................ .. .. 9 5 2 Proboscidea.. ... .. .... ........................ ... ...... ..... ... .. ..... 1 0 0 Perrissodactyla ...... ................................................ 6 3 1 Artiodactyla... ........... ..... .......... ..... ..... .... .. .. ............ 6 5 2 Totals ......... .......... ............ ... ........................... 41 34 13 TABLE 4 RESEMBLANCE OF THE RED BASIN AND QUARTZ BASIN SAMPLES RODENTS Suborder Family Red Basin Quartz Basin Species in Common Aplodontidae..... ....... . ..... . ... .. ...... ...... .. 1 0 0 Sciurimorpha Mylagaulidae ... ... .. ....... ..... .................. 1 0 0 Sciuridae ...................... ..... ............ ... ... 4 1 1 Castorimorpha Castoridae.... ...... ..... .. .... .. .... .... ... ... .... .. 1 2 0 Eomyidae .......... ......... ........... ........ ...... 1 2 1 Heteromyidae...... .. .......... ...... ....... .. .... 1 Cricetidae......... ............. .... ... .. ........... .. 1 Myomorpha 2 1 2 1 Zapodidae ..... .... ... ............ .. ... ......... ... .. 0 1 0 Totals ... ...... ... ... ...... ....... ...... .. ............. ....... ... ......... .10 10 4 TABLE 5 RESEMBLANCE OF THE RED BASIN AND QUARTZ BASIN SAMPLES INSECTIVORA Family Red Basin Erinaceidae.... ......... ............ ...... ........... .. ........ .... ...... .. ... .. 1 Metacodontidae............ ... ...... ... .. ............. ................. ...... 1 Talpidae ................... ....... ... ...... ....... ...... ............ ........... ... 4 Soricidae .. ... .. ... ..... ..... ..................... .... ........ .. ... ............... 4 Total. ............... .. .... ..... .. .. ... ..... ..... .............. ... ...... .. .. .10 Quartz Basin Species in Common 1 1 5 2 9 0 1 2 1 4 0 44.4% 0 40% 40% 0 33% 40% 38.2% Total 1 1 4 3 2 2 2 1 16 Total 2 1 7 5 15 1968 SHOTWELL: MIOCENE MAMMALS 15 ships between the faunas. Monosaulax typicus is found at Red Basin. M onosaulax progressus is present at Quartz Basin. These two beavers are of the same size and height of crown. The striids of the lower fourth premolar are more persistent in M. progressus and it possesses a short parastriid not seen in M. typicus. How- ever, the degree of development of stria and striids on the molars are similar in the two species. Accessory lakes appear on the teeth of M. progressus and a butress-like stylid is on the anterior face of the lower fourth premolar. The presence of a parastriid on the premolar of M. progressus might suggest advancement over M. typicus but in this case it appears to be a function of the more complex nature of the oc- clusal pattern of the teeth of M. progressus and more probably reflects diversity in the genus rather than phylogenetic trends. Merychippus seversus, common in the Red Basin fauna and M. brevidontus, a rare form there, are unknown at Quartz Basin. M. relictus and M. sp. ( comparable to M. californicus) are present at Quartz Basin and not at Red Ba- sin. The teeth of M. brevidontus are very low crowned and tend to be complicated. Those of M. seversus are higher crowned but less com- plicated. They represent horses of about the same size. M. sp. of Quartz Basin is a high crowned species, similar to the High Rock Can- yon M. cf californicus. M. relictus is a small horse only poorly known at other localities. It is present, however, in the Crooked River Basin of Central Oregon along with M. seversus and possibly in the Mascall. M. seversus and M. californicus are considered by Downs ( 1961) to demonstrate steps in a microevolutionary trend. This is, of course, in part dependent on the temporal relations of these species. Downs considers the Crooked Creek, Gateway, Skull Springs, Beatty Buttes, Sucker Creek, Virgin Valley and Mascall, the sources of the M. sever- sus samples, to be equivalent in age and all older than the High Rock Canyon or North Coalinga faunas from which the M. califomi- cus samples were obtained. This time relation- ship, however, is primarily based on the equid fauna (Downs 1956, p. 325) and thus is cir- vuitous at best, certainly not independent evi- dence as is suggested in his later paper (Downs 1961, p. 58). The M. seversus-M. californicus "microevolutionary trends" are said by Downs (1961, p. 58) to confirm the "control character trends" in the M erychippus-N annippus line. This is not surprising since the Merychippus- Nannippus "control character trends" were ob- viously the basis for the establishment of the temporal order of the M. seversus-M. californi- cus "sequence." Downs (1961, p. 60) allows that M. seversus and M. californicus may rep- resent two parallel lines of development but re- jects this as an alternative because he recog- nized no supporting evidence. Downs gives no evidence that M. californicus is younger than M. seversus nor does he recognize the likeli- hood that they are not directly related. Such "sequences" as Merychippus-Nannip- pus (see Stirton 1947) are picked in the first place to show what they are purported to prove. For instance if a Merychippus-Hipparion se- quence had been chosen no increase in height of crown over the Coalinga M erychippus would be evident. The time order of the forms shown is not established by any means. No two of the elements in the sequence even occur in the same depositional basin or biogeographic area. They represent specimens from Oregon, Cali- fornia, Nebraska, Kansas, and Texas. It is my opinion that five of the Miocene specimens rep- resent "stages of evolution" which were prob- ably contemporaneous or even reversed in time sequence. Certainly only three steps are present in the Pliocene part of the sequence. The so called "control character trends" really have no time control. The order of stages in the se- quence is determined largey by the "control character trends." The sequence is not a se- quence but is based on the assumption that a continuous gradual progressive change is the evolutionary rule. This same "sequence" is then used as a demonstration of the truth of this assumption. The use of "control character trends" of such sequences as M erychippus-N annippus to 16 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 temporally order species within a genus seems unsound to me for the following reasons; 1. Temporal controls are not based on inde- pendent sources of information but usually are circuitous. 2. Where absolute dates are available they do not confirm the temporal relationships pro- posed within provincial ages and even re- verse some trends. 3. Such an approach ignores the probability of contemporaneous diversification of char- acters, something rather common in living mammals. Thus biogeographic and envir- onmental differences are not allowed. The stratigraphic evidence indicates that the Red Basin, Merychippus seversus, and the Quartz Basin M erychippus sp. are probably contemporaries. Additional evidence is sup- plied by the occurrence of Merychippus sp. in the Butte Creek Volcanic Sandstone at locality 2471 between Red Basin and Quartz Basin. The mutual occurrence of M. relictis and M. sever- sus in the Mascall fauna and the occurrence of M. relictis at Quartz Basin further supports this conclusion. The differences between the Red Basin and Quartz Basin collections are thus not due to differences in age but most probably reflect syn- chronous diversity in the mammalian fauna of the region in the Barstovian. It was suggested earlier that two associations were apparently represented in the previously known samples of the Barstovian Northern Great Basin fauna, the Merychippus-Dromo- meryx and Hyohippus-Ticholeptus associa- tions. The names are derived from the common large mammals present. Previous collections, because of their composite nature, masked the differences but do show that if such associations are real they represented adjacent habitats. Early in the excavation of the main quarry at Red Basin UOloc 2495 it was obvious that M erychippus and Dromomeryx were the most common large mammals present. H ypohippus and Ticholeptus were not recognized from there until the sample was being prepared and then were very rare. A search was begun by part of the crew, as soon as the nature of the quarry was evident, to seek out a site which might pro- duce the expected Hypohippus-Ticholeptus as- sociation. In this we were only partially suc- cessful. Such an occurrence was found but it was not possible to retrieve a quantitatively useful sample. This locality, UOloc 2497, was in a massive volcanic sandstone quite unlike the lithology at UOloc 2495, but within the thin Butte Creek Volcanic Sandstone. Scattered about on the surface were a number of speci- mens, many partly or wholly incased in con- cretions. Immediately above this massive sand- stone was a conglomerate which also produced fossil vertebrates, some of which had weathered out. Excavation in the conglomerate produced a number of specimens, including M. seversus, preserved much differently than those encoun- tered in and on the sandstone below. This dif- ference in preservation allowed a simple means of recognizing float from the overlying con- glomerate and segregating it from the speci- mens derived from the sandstone. Only eleven species of mammals were present in the massive sandstone sample. Only three of the species rec- ognized were not present in the large sample from UOloc 2495, Liodontia furlongi, a masto- dont and Parahippus avus. Merychippus sever- sus abundant at UOloc 2495 was questionably present and no Dromomeryx specimens were found. Complete dentitions of H ypohippus and Tichleptus were present and were best repre- sented among the isolated teeth and partial ele- ments. This occurence strongly suggests that a H ypohippus-Ticholeptus association existed, however, in sitzi specimens led me to believe that a local concentration was not present but that the material was homogeneously dispersed throughout the outcrop exposed. No quantita- tive sample is thus available. A collection of similarly preserved specimens was made by James at Massacre Lake, Nevada and possibly represents this or a very similar association. The collections described here thus represent at least three associations within the total fauna 1968 SHOTWELL: MIOCENE MAMMALS 17 of the Barstovian of the Northern Great Basin. The nature of these associations and their quan- titative attributes will be discussed later in a more appropriate context. If the various collections referred to here represent different aspects of the same total fauna it seems inappropriate to refer to them as separate faunas. Rather than re-defining faunas and faunules I will discuss them by lo- cality with the understanding that they all are part of the Skull Spring fauna. Eventually some more realistic basis will have to be devel- oped for reference to mammalian collections. The birds and lower vertebrates from the lo- calities discussed here will be described sep- arately at a later date. Figure 9. ?Didelphid UO 22684, ocdusal view x 5, UOloc 2465. SYSTEMATICS ORDER MARSUPALIA FAMILY DIDELPHIDAE (Fig. 9) A single upper molar from UOloc 2465, Quartz Basin, U022684, apparently represents a didelphid near the size of Didelphis. The pos- terior labial portion of the tooth is missing. The protocone is prominent. The paracone and metacone are present, the paracone is slightly the larger of the two cusps. At least one stylar cusp may have been present at the anterior edge of the labial side of the tooth but abrasion has nearly removed it. A much smaller one appears to be just posterior to it and another just anterior to the point of breakage. The trasverse diameter of the tooth is 6.1 mm. An estimate of the anterior-posterior diameter is 4 mm. Until more complete material is avail- able the assignment of this specimen must be tentative. ORDER INSECTIVORA The insectivores were studied by J. H. Hutch- ison. His studies of the shrews and moles have been previously published ( 1966, 1968). His work on the erinaceids and metacodontids (1964) is included here. SUPERF AMIL Y ERIN ACEOIDEA FAMILY ERINACEIDAE Subfamily Echinosoricinae LANT ANOTHER/UM sp. indet. (Fig. 10 A, B) This genus is represented in the Northern Great Basin by only one specimen, U024283, from Red Basin, UOloc 2495. The specimen consists of a slightly worn left second molar. There is a prominent paralophid and high trigonid. The metaconid and protoconid are op- posite each other transversely as are the hypo- conid and entoconid. The protoconid and meta- conid are of equal height with the entoconid only slightly lower. The tooth is less stout than 18 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON in L. longirostrae and Ocajila makpiyahe but otherwise heavier than in other species of Lan- tanotherium. The talonid is slightly narrower than the trigonid. The tooth is 2.38 mm long and 1. 77 mm wide. Of the North American Lantanotherium, the Red Basin specimen seems to resemble most closely L. sawini (James, 1963) and the form from the Bopesta Formation (Webb, 1961) in the transversely opposite placement of the pro- toconid and metaconid. The relative width of the talonid to trigonid in the Red Basin speci- men more closely approaches the condition of L. sawini, however the hypoconid is closer to the metaconid than it appears to be in James' illustration ( Fig. 18, p. 56) of L. sawini. In this latter respect the Oregon specimen resem- bles its contemporary from the Bopesta. To make any assignments as to specific relation- ships on such small differences would be fruit- less until the variation within Lantanotherium has been demonstrated. ERINACEIDAE incertae sedis (Fig. 10 C-H) Two complete upper fourth premolars (UO 22348-U022349) and the talon of another (U022347), two second or third upper molars (U022004, U022062), and one adult (UO 22305) and one unerupted (U021971) sec- ond lower molar of ~n apparently undescribed erinaceid were present in the Quartz Basin sample, UOloc 2465. Each specimen seems to represent an animal roughly the size of Lantan- otherium sawini. These three isolated groups of teeth are here tentatively considered to repre- sent the same species largely on the basis of Figure 10. Erinaceidae, Lantanotherium sp. left M2 U024283 Red Basin, A labial view, B occlusal view x 10. Erinaceidae in- cetae sedis, Quartz Basin, left M2 UO 22305, C labial view, D occlusal view x 10, left P4 UO 22349, E occlusal view, F lingual view x 10, right M2 or 3 UO 22062, G occlusal view, H lingual view x 10. A c E G No.14 B D F H 1968 SHOTWELL: MIOCENE MAMMALS 19 similar form, relatively equivalent expected size, and exclusion on the basis of size, mutual- ity, or morphology from assignment to other forms in the fauna. The P4 is shaped somewhat like that of Sorex. At first it was thought this tooth belonged to a shrew judging from the deeply emargin· ated posterior border and the lack of a hypo- cone, but the massive roots and their similarity of coalition to those of the M2 in conjunction with the massive appearance of the enamel sug- gest erinaceid affinities. The paracone is similar to that of Erinaceus. There is no external cingu- lum, but a small ridge arises about halfway down the paracone and joins the labial extrem- ity of the anterior cingulum to form a small anterior extension ( parastyle?). The protocone is a small swelling of the anterolabial extremity of the tooth quite close to the base of the para- cone and separated from it by only a small notch. The posterior portion of the tooth slopes down sharply from the protocone and ectoloph. There is no hypocone, in fact, the region where it might be expected is depressed in relation to the general slope of the talon. This depression is elongate and parallel to the lingual border of the tooth. It appears to be the result of occlu- sion. The posterior border is sharply indented as in Sorex. There is no posterior cingulum, although the occlusal (?) depression appears to create one. The three roots are beneath the center of the ectoloph, anterior region of the paracone, and the talon respectively. All are strongly interconnected with each other by strong crests which fuse at the vertical axis of the tooth. The numerical assignment of the two molar teeth is difficult since some lines of erinaceids tend to greatly reduce or lose the M3• In such species the M2 then approaches a structural similarity to the M3 of other erinaceids. The complex morphology of the fossils in company with a reduced hypocone suggest a modified M2 • This tooth is somewhat like the M3 of Gale- rix, but the development of the hypocone results in an inflated posterolingual border. The proto- cone is large and also inflated as in Erinaceus and Meterix; it is joined by ridges to the meta- cone and anterior cingulum. The slight rise and swelling on the anterior ridge probably repre- sents the protoconule. The portion of the cingu- lum immediately lingual to the parastyle re- sembles the anterior ridge of the protocone. The paracone is set in from the labial margin and slightly concave labially which results in the formation of ridges connecting it to the para- style and mesostyle. The parastyle is prominent and as high as the metacone. The external cin- gulum extending from the parastyle loses its identity beyond the low mesostyle. The meta- cone is similar to the paracone but is slightly convex labially. The hypocone is transversely elongated, low, and inflated. It connects labial- ly with the posterior ridge from the protocone forming a slight eminence probably represent- ing the metaconule, which, in turn, joins the base of the metacone. In both specimens the roots have been broken away immediately be- low the base of the crown. The lack of wear and fairly, thin root walls indicate the relatively re- cent eruption of the teeth. The M2 is more than half as wide as long ( see Table 6) and bulb us ( exodaenodont?) in appearance. The metaconid and protoconid, as well as the entoconid and hypoconid, are di- rectly opposite each other transversely. The talonid is longer and lower than the trigonid but about equal in width. The hypoconid and entoconid are joined by a broad hypolophid and also connected to the cusps anterior to them by the inflated crista obliqua and entolophid respectively. The trigonid is crowded and perched on the tooth. The paracone is com- pressed and continuous with the protocone as in Lantarwtherium. The labial walls of the roots coalese but are cleft just under the center of the crown. There is a large deep, vertical channel on the lingual side of the roots opposite the cleft. The author was unable to examine specimens or descriptions of all the other genera of erin- aceids so that absolute exclusion of these speci- mens from known forms is not certain, but none described or examined by Butler ( 194 7) or the 20 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 author showed the high degree of confluence of the roots as in the P4 and M2 of this form. Lack of better material and positive association make naming and speculation as to its affinities pre- mature. TABLE 6 MEASUREMENTS OF THE TEETH OF ERINACEID incertae sedis Specimen Length P4 : UO 22348 ....... ............ ... 2.7e uo 33459 .. .......... ... .. ... .. 2.69 M2 : UO 22004 ... ............. ...... 1.91 uo 22062 ............. ......... 1.86 M2 : UO 21974* .......... ... .. ... .. 2.4e uo 22305 ............... ..... .. 2.53 e Estimated measurement. * Unerupted tooth. SUPERFAMILY SORICOIDEA FAMILY METACODONTIDAE Width 2.68 2.55 2.72 2.65 1.62 2.01 METERIX cf. M. LAT/DENS Hall Several teeth and a few mandibular frag- ments of M eterix were recovered from Quartz Basin, UOloc 2465. The skull material is being studied by S. David Webb who has at his dis- posal the type as well as a fine collection of jaws and teeth from Stewart Springs, Nevada. The Quartz Basin material represents the first M eterix from Oregon as well as its most north- erly occurrence. A number of peculiar limb bones of an insectivore of the size of M eterix were also recovered from the Quartz Basin site. The fragmentary humeri were soon recognized to be identical to a humeral fragment from Stewart Springs described by Reed and Downs (1958) as a "mammal of unknown affinities." The University of California at Berkeley has subsequently reworked the Stewart Springs lo- calities by washing techniques to yield many new specimens of M eterix but no additional humeri. There are, however, specimens of ape- culiar radius, femur, tibia-fibula, astragalus, and calcaneum which are essentially identical to the above mentioned homologous elements from Quartz Basin. The author believes that the post-cranial elements represent a single from on the basis of ( 1) recurrent association from the two sites, (2) relative size, (3) relative abundance, and ( 4) relative adaptive similar- ity. The association of the cranial elements of M eterix with the post-cranial elements is based on the first three of these criteria. Meterix is also present in the sample from Red Basin. Hutchison is preparing a report on the oste- ology of M eterix in which he will describe the Quartz Basin and Red Basin specimens as well as those from other Great Basin localities. ORDER LAGOMORPHA FAMILY LEPORIDAE HYPOLAGUS sp. A single upper P4 or M1, smaller than H. vetus but about the same size as the larger speci- mens of H. furlongi, was collected at UOloc 2453 Quartz Basin. The re-entrant is crenu- lated. Dawson (1958) assigned upper teeth from the Tonopah fauna to H. parviplicatus a species originally described from the Virgin Valley fauna. The Quartz Basin specimen is only slightly smaller than these. Transverse measurement = 3.75 mm. At locality 2465, Quartz Basin a fragmental tibia representing a small species of H ypolagus was found. ORDER RoDENTIA SUBORDER SCIUROMORPHA FAMILY APLODONTIDAE LIODONTIA ALEXANDRAE (Furlong 1910) Previously known material from the Skull Springs fauna is described in Gazin (1932) and reviewed by Shotwell ( 1958). Additional material was collected at UOloc 2459, Red Basin. FAMILY MYLAGAULIDAE MYLAGAULUS cf. LAEVIS The Red Basin material was described by Gazin (1932) and reviewed by Shotwell ( 1958). Additional material was collected at UOloc 2459, Red Basin. 1968 SHOTWELL: MIOCENE MAMMALS 21 FAMILY SCIURIDAE PROTOSPERMOPHILUS MALHEURENSIS ( Gazin 1932) (Fig. 11 A-C) The type and previously assigned specimens of this species do not include elements of the lower dentition. Isolated lower molars and pre- molars from Red Basin UOloc 2495 are as- signed here primarily on the basis of size and characters expected in the lower dentition, us- ing the lower dentition of other species of Pro- tospermophilus as a guide. The lower fourth premolar is subrounded, quadrate, in occlusal outline and slightly nar- rower transversely at the anterior end than the posterior. Anteroconid, mesoconid, entoconid, and mesostylid are all distinct. The parameta- conid and protoconid are in close contact. No protolophid or metalophid is evident. The posterolophid curves slightly and terminates at the high entoconid. The lower first or second molar is rhomboid- al in occclusal outline. The protolophid does not connect to the protocone in some specimens but bypasses it anteriorly, in others it is com- plete. The metalophid is low but complete. A small mesoconid is present on the ectolophid. Parametaconid, protoconid, and hypoconid are nearly equal in size, although the parameta- conid is highest. The entoconid is buried in the gently curving posterolophid but is distinct. A small mesostylid is present. In some specimens it appears as two small cusps, in others as a prominent single cusp. The lower third molar is represented by three well worn specimens so that all the char- acteristics are not clear. A small mesostylid and slightly larger mesoconid can be recognized. The protolophid is apparently complete and the metalophid very short. The tooth is broad at the small entoconid and tapers posteriorly to the hypoconid. One lower incisor is assigned to this species. In transverse section it is ovoid, flattened medi- ally. The enamel is crenulated. An upper in- cisor is also present with crenulated enamel. It is ovoid in transverse section, flattened medial- ly. Black (1963) indicates measurements for the upper incisor of the type specimen of P. malheurensis taken from specimen No. 129. However, the type has no incisors so the meas- urements must have referred to the alveoli. SPERMOPH/LUS TEPHRUS (Gazin 1932) (Fig. 11 D-K) Sciurus tephrus Gazin 1932, Carn. Inst. Wash. Pub.418,p.59 Citellus ridgwayi Gazin 1932, Carn. Inst. Wash. Pub. 418, p. 61 Protospermophilus tephrus Bryant 1945, Amer. Mid. Nat. Vol. 33, No. 2, p. 349 Citellus tephrus Black 1963, Bull. Mus. Comp. Zool, Vol. 130, No. 3, p.196 The lower dentition of this species was not represented in the material which was used in the original description. Since the present material was collected from the same strat- igraphic unit and since uppers which can be assigned to S. tephrus are also present the as- signment of the specimens described here is warranted. Three deciduous lower fourth pre- molars are in the collection. In this tooth the protoconid and parametaconid are conjoined at their base. The upper portions of these cusps are connected by a short metalophid and proto- lophid forming a small elevated trigonid basin. The hypoconid is about the same size as the protoconid. The posterolophid curves in a cir- cular arc ending just short of the parameta- conid. The tooth is much broader posteriorly than anteriorly. In the lower fourth premolar the protolophids is incomplete whereas the me- talophid is complete. The small trigonid basin thus opens anteriorly into a groove extending down the anterior face of the tooth. The proto- conid and hypoconid are of equal size and sep- arated by a rather straight ectolophid apparent- ly without a mesoconid. The posterolophid forms a parabolic arc and is low just before it connects with the parametaconid. The posterior 22 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No. 14 TABLE 7 MEASUREMENTS OF THE DENTITION OF Protospermophilus malheurensis lower dentition AP p4 U024238. ............. ....... ........... 1.87 M1or2 U024236... ........... .................. 1.88 U024404...... ..... .............. .. ..... 1.91 U024261........ ... ........ ............. 1.89 U024251...... ...................... .... 1.82 U024260 ....................... ......... 1.76 U024248 ................... ............. 2.00 Ms U024252 .. ......... .. .... ..... ....... ... 2.09 U024239 ..... ........ ........ ........... 2.38 U024263 ..... .......... .............. ... 2.23 I U024426 .. ..... ... .................... .. 4.28 upper dentition DP4 U024221........................ .. ...... 1.93 Ml or2 U024215 ...... ... ... .. .................. 2.45 U024241 ....... .. ................ ....... 2.01 I U024422 ........ ........................ 4.05 Tr 1.71 1.77 2.02 2.01 1.97 2.08 2.04 1.78 2.08 l.97a 1.89 1.88 2.52 2.52 portion of the tooth is much wider than the an- terior. In the lower first and second molars the pro- toconid and parametaconid are of about equal size while the hypoconid is smaller. The proto- lophid connects low and indirectly on the proto- conid producing a prominent groove and cusp at that point. The metalophid is very short and only meets a broadened protolophid from the parametaconid. A trench-like open trigonid basin is formed. The ectolophid is straight and on some specimens has a mesoconid. The pos- terior lophid curves gently around to the ento- conid which is submerged in it. A mesostylid is not apparent on any of the specimens. In the lower third molar the parametaconid and protoconid are of equal size while the hypo- conid is greatly expanded. The protolophid is complete and the metalophid very short. The posterolophid ends at the entoconid which is submerged in it. Some specimens have a small mesostylid. A poorly developed mesoconid is present on some specimens. Three fragmental lower incisors are present in the collection. Two of the specimens have 4-6 distinct longitudinal grooves near the middle of the enamel face while one has crenulations which are crudely aligned. These crenulations may, in part, represent abraded grooves since the specimen shows some evidence of abrasion. The type specimen and synonym type speci- men display well worn and damaged teeth. The new material thus provides some additional data concerning these teeth. The upper deciduous fourth premolar differs markedly from the permanent fourth premolar in the presence of a large parastyle. The an- terior cingulum connects high on the parastyle and low on the protocone. The anterior valley is thus closed off lingually. No protoconule is present but a metaconule is. The metaloph curves anteriorly connecting low on the proto- cone. A mesostyle is present on the shoulder of the paracone. The central valley is broad at its midpoint. The posterior cingulum is well devel- oped bordering a narrow posterior valley. Two of the specimens have no roots and two have highly divergent roots indicating the deciduous nature of the teeth. The broad parastyle on the deciduous dentition of a form having a much reduced parastyle on the permanent tooth is to be expected since this is characteristic in living sciurids. Neither of the upper fourth premolars in the collection have mesostyles which occur on the original material. However, the appearance of mesostyles is variable and their absence on the present material does not negate its assignment to the known species. The parastyle is low and poorly developed. The anterior cingulum is low and appears as a narrow shelf low on the an- terior side of the tooth. The protoloph is sinu- ous and a protoconule is either not present or completely incorporated in the protoloph which connects low on the broad protocone. A meta- conule is present on one specimen and only poorly developed on the other. The metaloph 1968 SHOTWELL: MIOCENE MAMMALS is quite narrow at its connection low on the protocone. The posterior cingulum is promi- nent and may incorporate the hypocone. The cingulum is higher and somewhat broader at this point. The upper first and second molars are nearly quadrate in outline. The protocone is large and dominates all the other features of the tooth. The parastyle is not separable from the ante- rior cingulum which is strong and connects abruptly into the protocone adding to the quad- rate occlusal outline. The posterior cingulum also contacts the protocone abruptly, a swelling at this point may represent the hypocone. The anterior valley is broader than the posterior. The protoloph drops sharply to a point low on the protocone where it makes a narrow connec- tion. A small protoconule is present on some specimens. A broad mesostyle is present. The metaloph appears to terminate in a relatively large metaconule, however, on some specimens a low narrow connection occurs just beyond the metaconule. There is no metaloph on the third upper mo- lar. The protoloph is straight and connects low on the protocone. The anterior cingulum is complete and borders a narrow valley. The pro- tocone is bulbous. The posterior cingulum forms an abrupt angle with the protocone and is semicircular in occlusal outline, the talon basin being expanded. The upper incisors in the type material are crenulated but the tip near the broken end of one on CIT 334 reveals longitudinal grooves. Upper incisors in the new material are finely crenulated. This species is similar in dention to the living Spermophilus beecheyi. Figure 11. Sciurids, Red Basin, Protospermophilus malheurensis, A P 4 U024235, B M1 or 2 U024404, C M1 or 2 U024261, Spermo- philus tephrus, D DP4 U024420, E P4 U024211, F M1 or 2 U024218, G M3 U024419, H DP4 U026056, I P4 UO 26055, J M1 or 2 U024246, K Ma uo 24231, Sciuropterus sp., L P 4 U024269, occlusal view, M lateral view, N P4 UO 24390 all x 5. A (fp D G ' H L ~ E ~ I 23 c B (9 • F G ~ : v J K N 24 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 TABLE 8 MEASUREMENTS OF THE DENTITION OF Spermophilus tephrus lower dentition AP Tr DP4 U024237 ___ ___ ___ __________ ___ ___ ______ _ 1.48 U026056... .. .. ....... ..... ... ... .. ... .. 1.46 p4 U026055..... ........... ... ... ... ....... 1.55 M1or 2 U024256.. ..... ... ... ... ...... ... .... ... 1.96 U024240 ..... ..... .. ........ .. ........ .. 2.00 U024250 .. ... .... ..... .................. 1.97 U024246 .......... ..... ... .. .. .... ... ... 1.79 Ma U02423L ........ ... .. .. ......... ..... . 2.13 U024242 .. ... ..... ...... ... ... .. ..... ... 2.12a U024255 ..... .... .... .... ..... ... .... ... 2.05 U024254........ ..... ......... ....... ... 1.96 U024253 ..... .. .. ..... ... .. ...... ....... 2.26 upper dentition DP4 U024408. .............. ....... ... ..... .. 1.56 U024219 ..... ..... .... .... ... ...... ..... 1.53 U024420 ..... .... .... ................... 1.69 U024232. .... .... .... ..... .... ... ..... .. 1.59 p4 U024211 ....... .. .... .. ............ ..... 1.59 U024214 ..... ......... ..... .. ........... 1.58 Mlor2 U024218.. ... ...... .. ..... ... ..... ...... 1.89 U024213. .......... .. ................... 1.80 U024228 ......... ..... .......... ........ 1.78 U024223 .. .. .. .... ... ...... ...... .. ..... 1.78 U024226 ...... ... ...... .... ... ... ... .. .. 1.77 U024234 ............. .... .... ..... .. .... 1.83 U024410... .. .. .. ...... .. .... .......... . 1.54 U024264. .... .... .... .. .... ... .... .... .. 1.81 Ma U024230.. ... ...... ... ................. . 1.98 U024220 ..... ..... ... .... .... .... .... ... 1.94 U024412 .... .. .... ... ................... 2.12 U024216 ... .. ..... ..... .. .... .... ... .. .. 2.00a U024212 ...... ... .. .. .. .. .. .. ... ... ... .. 2.12 U024418. .............. ..... ... ... ...... 1.92 U024419 ............. .... ..... .......... 2.37 I U027159 ... .... ... ..... .. .... .... ....... 2.53 U027165 .. ....... .......... ...... ...... . 2.62 U027163 ... .. ..... .... .................. 2.93 U027158. ......... ... ..... ........ .... .. 2.96 U027161 .. ... .... ..... ..... ...... .. ..... 2.69 1.25 1.31 1.40 1.93 2.08 2.01 1.67 2.00 l.97a 2.08a 1.95 2.06 1.35 1.52 1.52 1.64 1.80 1.71 2.33 2.29 2.17 2.08 1.92 2.12 1.96 1.99 2.00 1.94 1.84 1.94 1.91 2.32 1.50 1.42 1.67 1.72 1.39 Black ( 1963) considered the type skulls of Citellzts ridgewayi and Sciums tephrus to rep- resent the same squirrel and so placed them in a single species. The name chosen was appar- ently determined by page priority in Gazin's original description of the material. However, the characteristics of this form are more dis- tinct on the former species C. ridgewayi. In using the genus Spermophilus I am simply fol- lowing Hall and Kelson (1959) in its apparent priority over Citellus. SPERMOPHILLUS cf. TEPHRUS A scapholunar and two astragali from Quartz Basin locality 2465 represent a small species of spermophilid near S. beecheyi in characteristics. These are the only specimens assigned to the sciuridae from Quartz Basin. EUT AM/AS sp. A single upper fourth premolar of a very small sciurid occurs in the collection from Red Basin, UOloc 2495. The specimen is moderate- ly worn. The parastyle is low. The anterior cin- gulum extends about one half the transverse width of the tooth. The protoloph is straight whereas the metaloph curves anteriorly joining the protocone at about the same point. Proto or metaconules are apparently not present. It is not possible to determine the nature of the posterior cingulum or whether a mesostyle was present or not. The occlusal outline of the tooth and its size suggests Eutamias. U024225 AP 1.08 SCIUROPTERUS sp. (Fig. 11 L-N) Tr 1.36 Five teeth or tooth fragments represent this genus in the collection from Red Basin UOloc 2495. They include a little worn lower fourth premolar, two little worn upper fourth premo- lars, a fragment of an upper first or second molar and a heavily worn upper third molar. 1968 SHOTWELL: MIOCENE MAMMALS 25 In the lower fourth premolar the parameta- conid is the largest cusp and is situated more anteriorly than the protoconid. It exposes a flattened face to the talonid basin. The para- metaconid and protoconid are closely ap· pressed. A small accessory cusp appears on the anterior lingual face of the parametaconid which may represent a much reduced antero- conid. There is a groove separating it from the protoconid. The posterolophid is high and ter- minates at the prominent entoconid. A meso· style is present as well as a prominent mes~ conid. The ectolophid is situated well in from the border of the tooth and is relatively high. The floor of the talonid basin is rugose and crenulated. The parastyle is the largest cusp of the upper fourth premolar. The anterior cingulum is low and connects the lingual border of the para- style to the protocone. The anterior valley is therefore open. The protoloph is straight with apparently no protoconule. The metaloph curves slightly anteriorly and only weakly con- nects to the protocone. A metaconule is present. The paracone and metacone are of about the same size. The posterior cingulum extends nearly straight from the posterior side of the metacone to the hypocone. A mesostyle is pres- ent. The tooth is complicated by the develop- ment of numerous protolophules and metaloph- ules. Lophules are also present on the para- style, protocone and posterior cingulum. In one specimen the posterior valley is completely blocked in two places by lophules. Several prominent lophules extend into the central val- ley and anterior valley from the protocone. The highest development is in the posteriorly di- rected metalophules. The smaller of these two specimens is either an unerupted tooth or pos- sibly a deciduous tooth. It consists of only the enamel cap. Several species of Sciuropterus were de- scribed by James ( 1963) as the first known from North America. The present material is larger than James' material and apparently more complicated especially in regards to the posterior valley of the upper fourth premolar. In these two characteristics it is closer to S. al- banensis judging by James' review. The hypo- cone does not seem to be as prominent in the new material as in James' specimens but this may only reflect differences in stage of wear. Whether or not the Tertiary specimens as- signed to Sciuropterus are really flying squir- rels in habitus is not known. The assignment to Sciuropterus is a convenience in the same way that assignments in the past of Tertiary speci- mens to Sciurus and Citellus was convenient. The occurrence of complicated teeth in para- myids (see Wood 1962) and the marmot Mar- mota nevadensis elicits caution in any conclu- sions from this occurrence. U024269 U024390 U024270 AP 3.62 3.80 3.33 SUBORDER CASTORIMORPHA FAMILY CASTORIDAE Subfamily Castoroidinae Tr 3.31 4.23 3.48 MONOSAULAX TYPICUS n. sp. (Fig. 12) TYPE: U021677, left mandible with incisor, P 4-M3, palate with left P 4-M1, M3 and right p4.M3 HYPODYM: U0207 41, right mandible with com- plete dentition; U024395, fragmental left mandible with P4-M3 ; 0024394, fragmental left mandible with P 4-M1 ; 0024392, fragmen- tal right mandible with P4-M2 ; U024393, crushed skull with complete dentition; UO 21558, anterior portion of skull with complete dention. TYPE LOCALITY: UOloc 2495, Red Basin DIAGNOSIS: Small species in which the hypo- flexus and paraflexus bypass in the upper fourth premolar resulting in a deep pre-paraflexus area in the occlusal pattern. Lingual striids and labial striae not persistent. F ossettids of the lower teeth tend to be straight. Secondary fos- settids and fossettes rarely present. Incisors with rounded enamel face. 26 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 B D E F H I 1968 SHOTWELL: MIOCENE MAMMALS 27 DESCRIPTION: No metastriid or parastriid is present even in unerupted lower fourth premo- lars. The mesostriid is very short but the hypo- striid extends well down the enamel crown. The base of the tooth is not exposed on any of the available specimens. In early wear the para, meso, and meta fossettids are straight and of nearly equal length. In one specimen the meta- fossettid is represented by two lakes. In an un- erupted specimen there is a notch opening into the parafossettid anteriorly. In this same speci- men there is a prominent invagination of the anterior border of the parafossettid into the lake. The parafossettid of some specimens is crescentic. The lower first and second molars are quite similar. The mesostriid is very short and the metastriid only slightly shorter. The para, meso, and meta fossettids are parallel and straight and about the same length in early wear. In the course of wear the parafossettid be- comes very small and is the first lake lost from the occlusal pattern. Soon after the metafosset- tid is also lost. Late in wear only the large hypo- fossettid and a very small mesofossettid re- main. The anteroposterior diameter reduces with the loss of the fossettids while the trasverse diameter remains little changed. Occasionally the parafossettid is slightly curved. The third lower molar is a little smaller and shorter crowned than the others. The fossettids are unequal in size with the parafossettid much larger than the other lingual lakes. The me- sofossettid is the smallest. The upper fourth premolar is the largest tooth of the superior cheek tooth series. The labial stria of this tooth are closed in all the specimens available even those in apparent early wear. The parafossette is straight and by- passes the hypoflexus. The mesofossette is Figure 12. Monosaulax typicus n.sp., Red Basin, A left mandible P4·M3 UO 21677 labial view x l, B occlusal view x 5, C right mandible P4-M3 UO 20741 labial view x 1, D lingual view x 1, E occlusal view x 5, F palate U021677 x 2.75, G skull U024393 ventral view x 1, H dentition occlusal view x 5, I upper dentition UO 21558 occlusal view x 5. straight labially but at about the middle of the tooth it curves sharply posteriorly. The meta- fossette is straight and small. The upper first and second molars also have closed labial stria in all the available specimens suggesting that they are very short in unworn teeth. The para- fossette and hypofossette abut. The parafossette is quite small. The mesofossette curves poster- iorly at its lingual end but not as sharply as in the upper fourth premolar and tends to be more symmetrical. The metafossette is small and straight. In well worn specimens the metafos- sette is absent and the parafossette very small. By very late wear only the meso and hypofos- settes are present. The anterior-posterior dia- meter of the tooth is greatly reduced in the course of wear. The third upper molar is short- er crowned and smaller than the others. The metastria opens posteriorly and the metafos- sette appears to be more persistent than in the other molars. A small secondary fossette ap- pears between the labial ends of the para and mesofossettes. COMPARISONS: Only three previously described species of North American Monosaulax ap- proach M. typicus in its small size, M. com- plexus, M. curtis and M. n. sp. Wilson (1960). Of these only M. n. sp. Wilson from Quarry A in Martin Canyon, Colorado is adequately de- scribed. Comparison of upper and lower den- titions of the Colorado species, ( augmented by Wilson's description), with the Red Basin species reveals a number of similarities and differences. The two species have similar heights of crown and about equally persistent stria and striids. Secondary fossettes are either not as common or not as persistent in the Ore- gon species as in the one from Colorado. In the upper fourth premolars of the Colorado species the hypoflexus and paraflexus abut but in M. typicus they bypass. This emphasizes the larger proparafossette segment of the occlusal surface present in the Oregon species. In the upper cheek teeth of the Colorado species the meso- fossette is symmetrically crescentic whereas in M. typicus the mesofossette is crescentic but assymmetrical, the lingual portion extending 28 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON TABLE 9 MEASUREMENTS OF LOWER DENTITION OF Monosaulax typicus U021677 P4 AP---·--- -- -·------- ------------------- -- ---- --- -- ----- ----- 3.88 Tr .. ---- ------- -·········· ··---- ·--·- ---··- ······-··--····· ·· 3.52 Meso .. ... .......... ..... ....... ............ ............... . M1 AP...... ............. .............................. ...... ... 2. 70 Tr.......................... ...... ............. .............. 3.41 Hypo.- ------ --··----··----··-----·····-· ----· ----- --······· 0.69 Meso .......... .... .......... ---------------------------- -- - M2 AP-- -- ----··----····-·---- --····----·---···-----------·----- 2. 79 Tr_ ___________ ____ __ ____ ______ ____ _______ _________ ___ ______ __ 3.4 7 Hypo ........ -- ---- --- -- ------- ---- -- ---- -----··· ---- --·-- -· 0.65 Meso·---- ------·----·-···--·-- ---------- ---- --------------- Meta ...... ....... ...... ............. ..... ... .. ....... ..... . M3 AP----- -- ---------··-·-- -·----·----··· --·-·····--··--·-----· 3.06 Tr·--- -- --- ------ ------- ·-- ---·-----·------· ·---··- ---·· ----·· 3.14 Hypo .... -- ---------------- ---- ----·---- -- ---···· ---·------· 0. 72 P 4Ma- -- ------- --- -- --- ----····· -··· ········· ··------- ------ ----- ---- 12. 78 AP, Tr, occlusal diameter a-damaged, Hypo, Meso, Meta indicate striid lengths U020741 3.95a 2.82a 0.95 2.52 3.29 0.68 2.76 3.45 0.94 2.77 3.16 0.86 11.90 U024394 3.56 3.14 0.33 2.81 2.95 1.05 TABLE 10 MEASUREMENTS OF THE UPPER DENTITION OF M onosaulax typicus U021558L P 4 AP ·- ---- ------------ ----- -- ------ - 3.49a Tr --------------- ----····· ·-·-· --· 3.24 Hypo --- -------- -- --- -- ---------- 3.28 M1 AP---- ---- -- ------- --··-·-·· ··· ··· 2.76 Tr ·-·-·-····------------------·-·· Hypo -- ---- ------- --------------- 1.80 M2 AP -------·· ---···---·---- -··------ 2.83 Tr --- ---- --- ---- ----- -- ------ ----- 2.91 Hypo ----- ---- ----- ---- ---- ----- - 1.84 Ma AP -- ------ --- -- --- -- -- --- -- ---- --- 2.45 Tr -- ----- ---- ----------- --·····- -- 2.72 Hypo ·--·---··----------- ---- --- - 2.25 P4-M2 --- --- ---- -------- ----- ----- -- -·- --- 8. 75 p4.M3 ----- ----- ---- ---- --- ---- ----·-··--·11.26 U021558R 3.46 3.36 3.14 2.75 3.15 1.62 2.84 3.05 2.04 2.65 2.93 1.87 U021677L U021677R 4.57 4.42 4.01 1.01 1.01 2.79 3.11 3.10 2.93 0.36 3.05 2.42 1.24 ·a.so U024395 4.42 3.33 2.41 3.27 3.62 3.12 2.72 2.99 0.78 12.28 U024393L 3.99 3.71 0.61 3.17 3.05 3.03 3.04 3.13 3.00 0.81 8.88 11.67 No. 14 U024392 1.15 2.60 2.92 1.71 0.25 2.69 2.84 1.95 0.56 0.54 U024393R 3.92 0.60 j 1.22 8.48 l 11.20 1968 SHOTWELL: MIOCENE MAMMALS 29 much further posteriorly than the labial. These two species appear to represent a similar stage of evolution. Specimens of Monosaulax from Nevada and Oregon have previously been recognized and assigned to the species M. pansus (Douglas 1901, Stirton 1935). This is apparently a much larger species than M. typicus and also higher crowned. It lacks the secondary fossettes seen in the Colorado species but otherwise differs from the new species in some of the same char- acteristics as does the Colorado species. MONOSAULAX PROGRESSUS n. sp. (Fig. 13-15) TYPE: U021713, right mandible with P 4-M3 ; incisor and ascending ramus missing. HYPODYM: U019864, right mandible fragment including M1-M3 ; U019870, right mandible fragment including P4-M2 ; U019871, left man- dible fragment including P4-M1 ; U019860, right mandible fragment including P4-M2 ; UO 19876, maxilla fragment with M2-3 ; U019873, palate with left and right P 4-M3 ; U021714 pal- ate with left P4-M3 and right P4-M1 ; U026686 maxilla fragment with P4-M1 ; U019863 max- illa fragment with M1-M2 • TYPE LOCALITY: UOloc 2465 Quartz Basin DIAGNOSIS: Small species with a short parastriid present on the lower fourth premolar which differs from all other previously described species. A strong buttress-like stylid occurs on the anterior face of the lower fourth premolar. On the upper fourth premolar there is a strong anterior lingual groove on the anterior face of the tooth. Secondary fossettes are present in early wear. Incisors with rounded enamel face. DESCRIPTION: In addition to the hypodym, nine- ty five isolated teeth and a number of skeletal elements are present in the collection from the type locality. In the lower dentition the deciduous fourth premolar has no parastriid. The mesostriid and hypostriid are complete. The pattern is dom- inated by a large metafossettid and equally large parafossettid. The border of the para- fossettid is complicated by a number of enamel invaginations into the mesoflexid originating from the mesostylid. The permanent lower fourth premolar has a short parastriid. The mesostriid is more than three fourths the height of the enamel crown. The hypostriid is full length. A well developed buttress-like style ex- tends up the anterior face of the tooth and is reflected in the occlusal pattern after early wear. In early wear a small invagination of enamel projects from the anterior wall of the paraflexid, the metafossetid is very large and only separated by a narrow ridge of enamel from the hypoflexid, and roots are not yet de- veloped. In some specimens a small invagina- tions appears just labial to the stylid on the an- terior face of the tooth and results in a small secondary fossettid in the occlusal pattern in early wear. At the same stage of wear another secondary fossettid occurs on the mesostylid. The first and second lower molars are simi- lar and difficult to separate when isolated from the mandible. In very early wear parastriid, metastriid, mesostriid and hypostriid are all open. Of the lingual striids the mesostriid is the most persistent. The para and metastriids are much less persistent, the metastriid being very short lived. The hypostriid extends nearly to the base of the enamel. As the para and meta- striids close with wear the anterior-posterior diameter of the tooth becomes shorter at the occlusal surface. Eventually the parafossettid and the metafossettid are lost through wear further shortening the anterior-posterior diam- eter of the tooth. In addition to the primary fossettids a secondary fossettid occurs in early wear antero-lingual to the parafossettid. All the fossettids and flexids are very nearly straight. The parafossettid is o,rdinarily the longest of the lingual fossettids ~nd in the first lower mo- lar often curves slightly anteriorly at its labial end. The third lower molar is similar to the other molars but shorter crowned. In the upper dentition the deciduous fourth premolar is molariform in overall appearance. 30 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 A B E c F G H Figure 13. Monosaul.ax progressus n.sp., Quartz Basin, A mandible P4-M3 U021713 dorsal view x 2.5, B ocdusal view dentition x 2.5, C lateral view x 2.5, D medial view x 2.5, E palate U019873 ventral view x 2.5, F palate U021714 ventral view x 2.5, G DP 4 U022965 occlusal view x 5, H DP 4 U022959 occlusal view x 5. 1968 SHOTWELL: MIOCENE MAMMALS TABLE 11 MEASUREMENTS OF THE FOURTH LOWER PREMOLAR OF M onosaulax progressus AP Tr HC Hypo 0022953........ ...... ..... ......... ... ...... .... . 4.6 0022868 ...... ............ ..... .................. . 0022955.............. ... .............. ... ..... ... 4. 7 0022954.. ...... ............. ... .... ..... ......... 4. 7 0022966...... ..... ..... ... ........... ........ ... . 4.6 0022943 ............ ............ ..... ............. · 4. 7 AP, Tr greatest diameter 3.5 3.5 3.7 3.4 3.4 RC-Height of crown on lingual side, Hypo, Meso, Para indicate striid lengths 5.27 4.53 4.46 4.45 4.56 4.84 TABLE 12 MEASUREMENTS OF LOWER DENTITION OF Monosaulax progresus 6.74 4.62 5.34 3.90 5.30 31 Meso Para 3.90 1.70 2.95 0.40 3.16 0.38 2.32 0.72 2.65 0.72 2.21 0021713 0019860 0019871 0019876 0019864 0019870 P 4 AP ------ --- ------------ ------------- 3.63 Tr ----- ---- ------ -- -------- ----- ---- 2.69 Meso ---- ----------- ----- ---- --- --- 2.25 Hypo ... ------------ ----------- ---- Para ---- ------ ---· ················ 0.67 M1 AP ..... ...... .. .............. .. .. ... 2.91 Tr .. ... ....... ..... .... ..... ... ..... 2.97 Meso .......... ....... .. .. ..... .... 0.22 Hypo ---··· ····-------- --- ---- ----- M2 AP ..... .... ........ ...... .. ...... ... 2.79 Tr ... .............. .. ...... .... ..... 3.08 Meso .. ......... .. ........ ......... 0.79 Hypo ..... .... .... .... .... ...... .. . Para .............................. 0.23 M3 AP ......... .... .... ................. 2.86 Tr ·········------------------------- 2.85 Meso ........ .... ....... .... ....... 0.86 Para .. ... .. .... .. .......... .. .. ... 0.64 Met .. ....... ...... ................ . 4.98 3.82 1.32 2.39 3.59a 2.73 3.28 0.45 P 4-M2 . ..••.• .. . . ••..... . .. ........ ... .... . . 9.32 10.37 P 4-M3 . .... . . .. . . . .. . . . .. ... ...... ... ..... . . 12.27 AP, Tr occlusal measurements a. damaged, Hypo, Meso, Para, Met, indicate striid lengths 4.30 3.57 2.60 3.36 0.69 2.93 3.09 0.15 0.44 3.18 2.94 0.17 3.39 2.54 LOO 2.99 2.99 1.59 0.60 2.86 3.27 1.40 0.55 0.19 4.04 3.11 2.21 5.30 3.08 3,26 0.29 1.99 2.98 3.31 0.53 Notch 9.80 32 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No. 14 A B E D F J L M N 0 p Q \ 1968 SHOTWELL: MIOCENE MAMMALS 33 the parafossette and hypoflexus abut in early wear but bypass in later wear. The parastria appears only as a notch even in unworn speci- mens. The hypostria is full length. The meso- stria is short, less than one half the height of the enamel crown. There is a hook-shaped ex- tension of the paracone into the mesoflexus. The occlusal outline of the tooth is square but it is oriented diagonally in the maxilla. In the per- manent upper fourth premolar the labial stria are all short. The metastria is never more than a notch. The para and metastria are nearly equal and only about 1 mm in length in very early wear. Secondary fossettes occur on each of the transverse lophs, at the parastyle pos- terior to the paracone and anterior to the meso- style in early stages of wear. There is a shallow but prominent groove on the anterior lingual face of the tooth which is reflected in the oc- clusal pattern at most stages of wear. The hypo- flexus bypasses the paraflexus. The paraflexus, hypoflexus and metafossette are all straight but become irregular in late wear. The mesofossette is slightly curved asymmetrically. The lingual portion extends posteriorly parallel to the pos- terior border of the hypoflexus. The fourth pre- molar is much larger than the other upper cheek teeth. In the upper first and second molars the para- stria is very short closing early in wear. The mesostria is less than 1 mm long and the meta- stria is apparently closed at all stages of wear. The hypostria is nearly the full length of the enamel crown. Unlike the upper fourth pre- molar the hypoflexus and the parafossette abut in the upper molars. A secondary fossette ap- pears between the mesoflexus and parafossette Figure 14. Monosaulax progressus n.sp., Quartz Basin, variations in wear right lower fourth premolars, A U0229533 occlusal view, B labial view, Cantero labial view, D anterior view, E lingual view, F UO 22966 occlusal view, G labial view, H anterior view, I lingual view, J U019870 occlusal view, K labial view, L anterior view, M lingual view, N UO 22957 oc· clusal view, 0 labial view, P anterior view, Q lingual view, all x 5. in early wear. In unworn teeth this fossette opens labially. An anterior extension of the mesostyle nearly closes off the mesoflexus on some specimens and forms a loop connecting to the posterior border of the mesoflexus resulting in a secondary fossette. In other specimens a small style · appears in the mesoflexus at the point of connection of the subsidiary loph. In early wear the occlusal pattern is reduced to a shortened straight parafossette, crescentic mesofossette, straight metafossette and a rela- tively straight hypoflexus. With wear the para- fossette becomes shorter and the hypoflexus longer accompanied by a reduction in the an- terior-posterior diameter of the occlusal sur- face. The parafossette and metafossette are lost before the base of the hypostria is reached. The third upper molar is similar in pattern to the first and second but is smaller. The anterior- posterior diameter of the occlusal pattern is not so drastically reduced in the course of wear. The metafossette and parafossette are appar- ently more persistent. COMPARISONS: The Quartz Basin species differs from all previously known species of Mono- saulax in the appearance of a short parastriid on the lower fourth premolar, a strongly devel- oped stylid on the anterior face of the lower fourth premolar and a strong anterior lingual groove on the face of the upper fourth premo- lar. It is a small species comparable in size to M. typicus, M. n. sp. Wilson, M. curtis and M. complexus. The character of the fossettes and fossettids is similar to M. typicus but secondary fossettes are present as in M. n. sp. Wilson. Complications of the basic enamel pattern oc- cur in early wear but are not similar to those present in the known specimens of M. com- plexus and do not persist with wear. The striids of the lower fourth premolar are longer than other species of M onosaulax but this is not true of the other teeth, nor is the height of crown significantly greater. Li ( 1962, 1963) has described two new species of M onosaulax from China and Inner Mongolia. M. changpeiensis exhibits secondary 34 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No. 14 B c D ~ E F~ G H J 1968 SHOTWELL: MIOCENE MAMMALS 35 TABLE 13 MEASUREMENTS OF THE FOURTH UPPER PREMOLAR OF M onosaulax progressus AP Tr U019867 ........ ................... ............... 3.7 3.8 U022951 .... ........ .... ....... ..... ...... ......... 3.7 3.7 U022894 ........ ........ .... ..... .... .... ....... .. 3.3 3.3 U022948. .. .. ...... .. ....... .... .......... ..... ... 3.6 3.8 AP, Tr, greatest diameter, Hypo, Meso, Para, Met indicate stria lengths Hypo Meso Para Met 6.50 0.82 1.19 0.42 2.44 3.42 4.91 0.46 TABLE 14 MEASUREMENTS OF UPPER DENTITION OF Monosaulax progresus U021714L U021714R U019873L p4 AP ......... ... 3.92 Tr .. ..... .. ... 3.78 Hypo ___ __ ___ 2.13 Para .... .. . . Meso ..... .. . M1 AP ....... ..... 2.22 Tr .......... .. 3.29 Hypo ..... .. . M2 AP ... .... .. ... 2.66 Tr .......... .. 3.03 Hypo ....... . Meso .. ..... . M3 AP ........... . 2.85 Tr ...... ...... 2.95 Hypo ..... .. . p4.M2 .. ..... ..... .... 8.90 P4-M3 .. .. . • .•. • . •• .•• 11.64 AP, Tr, occlusal 4.00 3.99 2.36 2.35 3.31 3.67 3.49 3.95 0.28 2.94 3.32 2.03 2.88 2.97 2.34 2.57 2.67 2.06 9.13 11.53 a-damaged, Hypo, Para, Meso, indicate stria lengths fossettids, lacks a parafossettid and is consid- erably larger than either of the species de- scribed here. M. tungurensis is higher crowned Figure 15. Monosaulax progressus n.sp. , Quartz Basin, variations in wear upper fourth premolars, A U019867 occlusal view, B labial view, C lingual view, D UO 19862 occlusal view, E antero labial view, F U022948occlusal view, G labial view, H lingual view, I U022951 occlu- sal view, J labial view, K lingual view, all x 5. U019873R U026686 3.71 3.52 3.53 1.40 4.12a 4.20 1.91 2.68a 3.31 0.43 U019863 2.89 2.94 3.13 2.80 3.29 0.43 U019862 3.45 3.52 5.18 0.34 0.33 2.59a 1.91 than M. changpeiensis, has parafossettids as well as secondary fossettids. It is also a larger species. Li considers M. changpeiensis to repre- sent an earlier evolutionary stage than M. tun- gurensis. DISCUSSION: In early wear the lower dentition superficially resembles that of Eucastor. The transit " rabbit pattern" of the lower fourth pre- molar and the straight fossettids give this effect. The deciduous lower premolar is, however, similar to other species of Monosaulax in its 36 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 single lingual striid. The stria and striids of the molars are short as in other species of Mon- osaulax. In size this species compares closely with the known smaller species of Monosaulax. The characteristics which distinguish this species from all previously known species of Monosaulax also distinguish it from all known species of Eucastor. In addition the molars do not exhibit the S pattern at any stage of wear because of the persistence of the parafossette, (parafossettid) and the early closure of the mesoflexus ( mesoflexid). These points argue for the inclusion of this species in Monosaulax rather than Eucastor. If the diagnoses of these genera as presented by Stirton ( 1935) are fol- lowed literally, M. progressus could not be as- signed to either genus. I believe the best assign- ment at this time is to the genus Monosaulax. The Eucastor-like characteristics present on this low crowned form suggest parallelism rather than transition. A B Figure 16. Macrognathomys sp., Quartz Basin, A M1 U022968, B P4-M1 U022967, both x 15. ? MONOSAULAX sp. Foot elements of a castoroid beaver nearly thirty percent larger than Monosaulax progres- sus are also present in the Quartz Basin collec- tion from locality 2465. No significant differ- ences are to be seen between these elements and oomparable specimens representing M. pro- gressus other than size. Since a much larger species of Monosaulax is known from the Vir- gin Valley fauna ( Stirton 1935) to the south it is not surprising to see a large castoroid in the Quartz Basin fauna. Monosaulax is not the only castoroid beaver that could be expected at this time and place or of the indicated size. The assignment is thus a very tentative one. SUPERF AMIL Y DIPODOIDEA FAMILY ZAPODIDAE Subfamily Sicistinae MACROGNATHOMYS sp. (Fig. 16) In the Quartz Basin fauna (UOloc 2465) a very small sicistine rodent is present. It is rep- resented by a mandible fragment including a M1 and a maxilla fragment including P4-M1 • The lower first molar has a small anteroconid but it is connected to the protoconid by a nar- row lophid. There is a low but definite ecto- lophid which extends to the margin of the tooth. A prominent mesostylid is present but is not connected to the short mesolophid, rather an accessory lophid connects the mesostylid to the base of the metaconid. A prominent hypoconu- lid is present on the posterior cingulum. This cingulum terminates in a stylar cusp. Two ac- cessory lophids are present in the post ento- conid valley. The tooth is only slightly smaller than that of Plesiosminthus clivosus Galbreath (1953) (see also Wilson 1960). It differs from P. clivosus in the connected anteroconid, pres- ence of an ectoloph1d and in the presence of ac- cessory lophids. The upper fourth premolar is nearly round. On the posterior labial side there is a prominent cusp bounded by two valleys. This elongated 1968 SHOTWELL: MIOCENE MAMMALS 37 cusp and its adjacent valleys occupies the labial half of the tooth. The lingual half is nearly as high as the prominent cusp and has three small cuspids on it. This is somewhat different than the P4 of P. clivosus in which the pattern is much simpler. The first upper molar has a prominent an- teroloph with an expansion, probably the an- terocone. The mesostyle is strongly connected to the central portion of the tooth by a mesoloph and to the paracone by a short cingulum. The metacone is connected by two metalophs, one of which is much smaller than the other and branched. The posterior cingulum connects the metacone and hypocone and has an additional pair of short accessory lophs connecting to the metacone. These lophs do not occur on the M1 of P. clivosus. The presently known material of both species is too scanty to thoroughly eval- uate the differences noted between the Quartz Basin species and P. clivosus. If the available material is representative of them then the Quartz Basin species may represent a form intermediate between P. clivosus and Macro- gnathomys nanus Hall (1930). 0022967 AP 0.46 p4 Tr 0.57 AP 0.94 ORDER CARNIVORA SUPERF AMIL Y CANOIDEA FAMILY CANIDAE Subfamily Caninae TOMARCTUS cf. KELLOGG/ (Merriam 1911) (Fig. 17 E, F) M1 Tr 0.86 Several mandible fragments, including teeth, two maxilla fragments and several isolated teeth in the Red Basin collection represent a canid with narrower and slightly smaller teeth than Tomarctus rurestris. The mandibles al- though slightly crushed are much lighter than T. rurestris. The metaconid of the lower first molar is proportionally larger on this canid than on T. rurestris but the heel is very similar. In these characteristics this material agrees with T. kelloggi from the Virgin Valley fauna. In using the combination T omarctus kelloggi I follow Matthew (1924) and Green (1948). Green in his assignment suggests that this broad genus gave rise to Osteoborus and Canis. The specimens assigned here to T. kelloggi show striking similarity to Hemphillian species re- ferred to Canis. TOMARCTUS cf. RURESTRIS ( Condon 1896) (Fig. 17A) A mandible (0024191), lacking only the anterior ventral portion, with P4-M1 present and a maxilla fragment (0024192) including the P4 apparently represent an old individual of Tomarctus rurestris. Isolated teeth and a badly crushed palate are also assigned to this species. These specimens exhibit the heavy jaw, rather broad cheek teeth, and strong curvature of the ventral border of the mandible seen in T. rurestris. Measurements of the teeth are close to those of the type specimen. Previously known material from the Skull Springs fauna was assigned to T. brevirostris by Gazin ( 1932) . Subsequent! y Downs ( 1956) assigned the material to T. rurestris after restudying the type. Canid sp. A very small canid is represented at OOloc 2465, Quart Basin, by a fragmental M1 in a mandible fragment, a canine and a premolar. The size of these isolated elements indicates a small canid about the size of Urocyon. The Mi, 0019752, lacks the heel so that without these characteristics the assignment of the species must be provisional. The trigonid of the M1 ex- hibits a high protoconid, much higher than the paraconid, and a small metaconid closely ap- pressed to the protoconid. There is no labial or lingual cingula. The M1 is estimated as having been 11 mm long when complete. The mandible below the M1 is 10 mm deep. The canine, 00 38 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 A B c E G F 1968 SHOTWELL: MIOCENE MAMMALS 39 26748, is laterally compressed. The premolar, U0267 49, has a prominent heel with a small cusp close to the posterior border. This small canid differs from Urocyon in the lack of an ac- cessory cusp on the labial side of the proto- conid. The available materials allows only a family designation. Subfamily Amphicynodontinae ? HEMICYON sp. A low crowned second or third lower molar is present in the Quartz Basin fauna as repre- sented at UOloc 2465. The specimen consists of the crown only with no indication of the num- ber of roots which may have been present. The tooth measures 10.9 mm long antero-posterior- ly and 8.8 mm transversely. The proportions indicate a tooth too wide proportionately for a canid. The very low crown obviates assignment to any canid. The proportions suggest a bear or bear-dog. Subfamily Amphicyoninae AMPHICYON sp. A large axis vertebrae and calcaneum from locality 2495, Red Basin, are assigned to Am- phicyon. The characteristics of the vertebrae are similar to those of Amphicyon riggsi as il- lustrated and described by McGrew ( 1939). The calcaneum, although slightly crushed, agrees with those described by Olsen (1960). Gazin (1932) previously recognized Amphi- cyon sinapius and A mphicyon cf. f rend ens in the Skull Springs fauna from fragmental den- tal elements. The new material does not pro- vide any basis for specific assignment. Figure 17. Carnivores, A T omarctus rurestrus right mandible U024191 Red Basin x 1, B Brachypsalis sp. P4 U019753 Quartz Basin, x 1, C Mustella sp. U019451 Quartz Basin, x 4.25, D Pseudaelurus sp. M1 U021564 Red Basin x 1, E To- marctus kelloggi M1- 2 U021559 Red Basin dorsal view x 1, F lateral view x 1, G Pseudaelurus sp. canine U023469 Red Basin x 1. FAMILY PROCYONIDAE BASSARISCUS sp. A fragmental upper first molar with the para- cone broken away, U022683, strongly resem· hies that tooth of Bassariscus. This specimen from Quartz Basin, UOloc 2465, has a strong protocone extending as a loph to the paracone. The metacone is small and set in from the labial and posterior borders of the tooth. There ap· pears to be no metaconule. The hypocone is low. The smooth area between the hypocone and protocone extends as a cingulum around the anterior border of the tooth to the paracone. The antero-posterior length of the tooth is esti- mated at 4.0 mm. The transverse diameter is 5.8 mm from metacone through the hypocone. FAMILY MUSTELIDAE MUSTELA sp. (Fig. l 7C) An anterior fragment of the mandible of a small mustelid including the P4, U019451, was recovered at Quartz Basin, UOloc 2457. An iso- lated P4 of similar size, U022302 was recov- ered from UOloc 2465. Both specimens may represent a single species. The anterior pos- terior diameter of the P4 of U019451 is 2.9 mm, of U022302 is 2.5 mm. The mandible is 3. 7 mm deep below the single tooth present. This species is the size of the weasel M ustela erminea and compares closely with it in as much as the scanty material will allow. Mus- tela buwaldi of the Ricardo fauna has acces- sory cusps on the P 4 and is a larger animal. Pliogale furlongi of the Thousand Creek fauna is in the same size range, however, the available material of the two forms does not allow direct comparisons. It seems best to refer the two specimens to Mustela noting the strong resem- blance to M. erminea at least for the present. Martes (Tomictis) gazini Hall (1931) from the nearby Skull Springs fauna is a much larger form. 40 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 BRACHYPSALIS sp. (Fig. l 7B) An upper fourth premolar, U019753, from Quartz Basin UOloc 2465 represents a moder- ate size mustelid. The protocone is well sepa- rated from the paracone and is a broad flat sided cusp facing the paracone. A strong cingu- lum extends from the protocone to the base of the paracone then posteriorly along the meta- cone to the posterior border of the tooth. The parastyle area is damaged. The size and char- acter suggest that this specimen represents a species of Brachypsalis. A large upper canine, U019755, may also represent this genus. A mustelid upper molar from Red Basin, UOloc 2495, is the size of the M1 of Brachy- psalis and is similar in characteristics although more triangular in occlusal outline than most. The anteroposterior length is 8.1 mm. The transverse width is 10.7 mm. SUPERF AMIL Y FELOIDEA FAMILY FELIDAE Subfamily Nimravinae PSEUDAELURUS sp. (Fig. 17 D-G) An upper canine, U023469, a lower M1 and a fragment of a P4 all from Red Basin locality 2495 are assigned to Pseudaelurus. The M 1 has a well developed trenchant heel and is 16.1 mm long. ORDER PROBOSCIDEA SUBORDER ELEPHANTOIDEA Family and Genus indet. A calcaneum, U024044, from UOloc 2491, tooth fragments from other Red Basin sites and tooth fragments from the Wildcat Creek lo- cality, UOloc 2345, indicate the presence of a mastodont but do not provide enough informa- tion to determine whether it represents Mio- mastodon or Gomphotherium. ORDER PERISSODACTYLA SUBORDER HIPPOMORPHA FAMILY EQUIDAE Subfamily Anchitheriinae PARAHIPPUS cf. AVUS Parahippus is sparsely represented in the Red Basin localities. UOloc 2497 produced a lower molar and an upper molar and UOloc 2496 produced a lower DPm. In the upper mo- lar (U022207) the protoloph does not connect to the protocone. The protocone is well isolated. The protoloph connects very low on the ecto· loph. A crochet is present and connects low on the protoloph. No internal cingulum is present. The hypostyle is isolated. Ribs are only slightly developed on the ectoloph between the styles. No cement is present but this is probably an artifact of exposure. On the lower tooth (UO 23870) there is a cingulum only on the antero- TABLE 15 MEASUREMENTS OF THE DENTITION OF H ypohippus sp. Tooth UOloc2497 U023840 ..................................... ......... .. ... ... M1 U023840 .................... ................. ....... ........ .. M2 U023840 ... ....... ................. .. .. .. ..................... Ma U023862 .. ...... ....... .... ......... ..... ................... .. P2 U023862 .... ................. ............ ................... .. Pa U023897 ........ ..... ................. ........... ...... ....... Pa ? UOloc2495 U020617 ......... ...... ............. ........... ......... .... .. P2 U021539 .... ....... ............. ..... ..... ..... .. ............. Pa U023520 ... ................... ............. .. .... ...... ....... M1? AP 24.3 22.1 23.7 26.5 24.3 22.8 22.8 23.0 21.1 Tr 17.3 15.9 13.8 15.0 16.5 16.0 14.2 16.8 16.9 l t 1968 SHOTWELL: MIOCENE MAMMALS labial side of the tooth between the hypoconid and protoconid. The mesoconid and mesostylid are separated to the base of the tooth. The ento- conid is bifurcated forming a complex crown. The hypoconulid is present but damaged. The upper molar measures 16.6 mm antero-pos- teriorly and 20.8 mm transversely. The lower A molar measures 20.9 mm antero-posteriorly. These specimens agree with the revised diag- nosis of P. avus and are referred to that species. HYPOHIPPUS sp. (Fig. 18) Three localities in Red Basin have produced specimens of Hypohippus, UOloc 2497, 2496 and 2495. The material consists primarily of lower dental elements including several man- dibles. Several complete and fragmental iso- lated upper teeth are present. The P2 of this species is very narrow anteriorly. There is no apparent metaconid. A cingulum originates in a reduced hypoconulid and extends to the base of the tooth, labially, and then anteriorly around the base of the tooth. It is absent or greatly reduced at the protoconid then contin- ues to the anterior edge of the tooth rising abruptly to the occlusal surface. On the Pa and P 4 the metaconid and metastylid are separated by a short lingual groove. Below this groove the metaconid and metastylid combine in a broad flat lingual face. A well developed hypo- conulid is present and the accompanying cingu- lum is prominent. It extends around the hypo- conid and protoconid to the parastylid without interruption in most specimens. In one, speci- men (0021539) a Pa, the cingulum is inter- rupted in the same manner as on the P 2• The P 4 is the largest lower premolar and apparently larger than any of the lower molars. Figure 18. Hypohippus sp., A right mandible P2-4 U023862 Red Basin occlusal view den- tition, B medial view, C lateral view, D left mandible M1-a U023840 Red Basin occlusal view dentition, E medial view, F lateral view, all x 0.75. B D 41 E 42 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 The M1 is the largest of the lower molars. The metaconid and metastylid are less sepa- rated on all the lower molars than on the pre- molars. The hypoconulid of the M1 and M2 is not as well developed as on the premolars. The cingulum, however, is strong and uninter- rupted. It appears to merge with the anterior face of the paralophid rather than joining a parastylid. A small cusp is present at the lin- gual edge of the metaflexid of all three lower molars and another small cusp is present at the lingual edge of the entoflexid of all three lower molars. On the Ma the metalophid is sep- arated from the metastylid by a prominent nar- row groove. The hypoconulid is developed into a third loph but is lower than the entoconid. The cingulum extends around the posterior margin of the base of the hypoconulid. There is a small cingular cusp on the labial side of the hypoconulid. The entoconid is simple on the premolars although it broadens antero-posteri- orly with wear. On the molars it is a broader cusp antero-posteriorly even in early wear. The upper tooth fragments indicate that the postfossette is closed off by the metaloph and hypostyle while the prefossette remains open. A cingulum is present at the base of the ecto- loph between each of the adjacent styles. The enamel of the teeth of one of the man- dible fragments is horizontally striated while that of the other is crenulated. In another specimen the crenulations appear to be oriented giving a fluted appearance. The new material agrees with that described by Gazin (1932) and as he previously stated compares closely with the Virgin Valley species. Subfamily Equinae MERYCHIPPUS SEVERSUS (Cope) (Fig. 19-22) Recent work by Downs (1956, 1961) has provided a much more workable base for as- signing specimens to the Great Basin species of Merychippus than previously existed. A large amount of equid material including pal- ates, mandibles, and appendicular skeletal ele- ments was recovered from UOloc 2495 in Red Basin. Nearly all of this material is assigned to M. seversus. Measurements of thirty isolated upper premolars and molars agree with those for specimens from the type area. Downs, in his study of specimens from both the Skull Springs and Mascall faunas, saw no significant differences between these two samples. The new material provides no basis for any other con- clusion. Localities UOloc 2497 and 2498, also in Red Basin, have yielded specimens which are assigned to M. seversus. The occurrence of a number of mandibles with deciduous or permanent dentition pro- vides unusually good material for a description of the lower dentition. The anterior cingulum of the DP2 extends from the lower labial side of the anterior face of the tooth diagonally upward to the paraloph- id. The paralophid terminates in a cusp about the same size and shape as the metaconid. The metaconid and metastylid are well separated and ovoid in occlusal outline. The metastylid is slightly the larger. The entoconid has an an- terior spur. The hypoconulid and the hypo- stylid form a cingulum-like structure which is recurved to the lingual border of the tooth. A short protosylid is present between the proto- conid and hypoconid. The DPa and OP4 resem- ble the DP2 except in the attenuated distal end of the paralophid and the presence of a cingu- lum at the base of the protoconid. The deciduous teeth have cement present at the base of the labial side of the teeth. The enamel of the teeth is crenulate. The adult lower incisors have a shallow broad fossette which on the Ia opens lingually. The canine is simple but possess a sharp loph on its anterior face. The first preµiolar is pres- ent on young individuals and only occasionally on older adults. It is a simple single rooted tooth. The crown is bulbous, slightly pointed near its crest and has a small loph on the an- terior face and also the posterior face. On the second premolar the paralophid is bifurcate distally. The metaconid is greatly re· - -------- 1968 SHOTWELL: MIOCENE MAMMALS 43 A B Figure 19. Merychippus seversus inunature, mandible DP2-4, U022765 Red Basin, A dorsal view, B medial view, C lateral view, all x 0.75. 44 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 A Figure 20. Merychippus seversus immature, mandible DP2-4 M2 U023216 Red Basin, A dorsal view, B lateral view, C medial view, all x 0.75. 1968 SHOTWELL: MIOCENE MAMMALS 45 A B c D Figure 21. Merychippus seversus lower dentition, Red Basin, A Pa-Ma UO 23437 labial view, B occlusal view, C P1-Ma U021038 labial view, D occlusal view, all x 0.75. 46 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No. 14 A c Figure 22. Merychippus seversus upper dentition, Red Basin, A P2-M3 U022830 labial view, B occlusal view, C P1-M3 U023440 labial view, D occlusal view, all x 0.75. 1968 SHOTWELL: MIOCENE MAMMALS 47 duced but becomes evident in late wear situ- ated antero-labially to the metastylid and only poorly separated from it. The floor of the meta- flexid has a single invagination. The floor of the entoflexid has a prominent invagination or sometimes two small ones. There is an anterior spur on the entoconid. The hypoconulid is well separated from the entoconid. The hypostylid is prominent. The paralophid of the lower third and fourth premolars is straight and attenuated distally. The parastylid proceeds diagonally across the anterior face of the tooth and does not contribute to the occlusal pattern until late wear. The metaconid and metastylid are sim- ilar in size and separated by a shallow groove. In some specimens there is a spur on the an- terior face of the metaconid. lnvaginations of the floor of the flexids are present. In some specimens a plication is present on the anterior wall of the entoflexid. An anterior spur of the entoconid occasionally blocks the opening of the entoflexid. The hypostylid is well separated from the entoconid. The hypoflexid almost com- pletely separates the anterior and posterior moieties of the premolars. The lower first and second molars differ very little from the third and fourth premolars. The molars are smaller and there is a stronger de- velopment of the parastylid on the first molar. The lower third molar has a posterior loph con- sisting of the hypoconulid and hypostylid and is strongly recurved forming an additional flex- ure in the tooth. MERYCHIPPUS cf. BREVIDONTUS Studies of a number ,of Northern Great Basin Barstovian faunas have revealed the occur- rence of a species of Merychippus with low crowned teeth. Scharf ( 1935), Bode ( 1934, 1935) and Downs (1956) have reported these occurrences from the High Rock Canyon, Skull Springs, Sucker Creek and Paulina faunas. Downs has also recognized this species in the Mascall fauna of the John Day Basin. Bode and Scharf assigned the High Rock Canyon, Skull Springs and Sucker Creek specimens to M. brevidontus Bode. Downs, however, pointed out that although these specimens are low crowned and of the lateral dimensions of M. seversus they did not appear to be as compli- cated in dental pattern as the typical M. brevi- dontus. Our localities in Red Basin, UOloc 2495, 2497, and 2498 representing the Skull Springs fauna have produced a small number of specimens representing a species of Mery- chippus of about the size of M. seversus but with low crowned teeth. An · upper molar series (U022748) (UOloc 2495) displays a large number of plications in the position of the pli prefossette. Other specimens are in early stages of wear so that observations of the complexity of the pattern are of limited comparative value. These specimens are assigned here to M. brevi- dontus with some hesitance. MERYCHIPPUS sp. (Fig. 23) The Quartz Basin fauna includes a species of M erychippus with teeth similar in size to those of M. severs us except in height of crown. A series of twelve upper premolars and molars from UOloc 2465 are little worn to unworn and have an average height of crown of 35.8 mm with a range from 34.6 to 43. 9mm ,much high- er than M. seversus but similar to specimens from High Rock Canyon and Virgin Valley ( see Downs 1961) . The average, although higher than that of M. californicus, may not be significantly higher. The protocone, in slightly worn specimens from UOloc 2465, is ovoid and in some specimens lacks a spur. Several addi- tional specimens from other Quartz Basin lo- calities apparently represent this same species. Some are moderately worn and reveal a rela- tively simple pattern of plications. The hypo- conal groove is open and an anterior cingulum is present on the teeth but only poorly devel- oped. A little worn lower M2 (U019711) associ- ated with the upper teeth reveals something of the character of the lower dentition. Other lower teeth are unworn. On U019711 the meta- conid and metastylid are small and rounded but 48 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No. 14 TABLE 16 MEASUREMENTS OF UPPER PREMOLARS AND MOLARS Merychippus sp. Stage Height of Wear crown UOloc2465 U019690 P3 u 34.6 U019698 P3 u 35.0 U019680 P3 u 33.9a U019687 P3 u 34.9 U019691 P4 s 40.5a U019689 P4 s 39.7 U019692 Ml s 39.1 U019686 Ml s 43.9 U019693 Ml s 39.6 U019694 M2 u 33.7 U019695 M2 u 34.1 U019685 M2 s 32.0 UOloc2457 U019435 M2 M 23.8 UOloc2463 U019665 P4 u U019667 M2 u 25.4 UOloc2455 U019272 M2 M 25.9 U019271 M2 M 22.7 U019266 M2 M 23.0 UOloc2456 U019319 M2 u 32.0 U- unworn, S-slightly worn, M-moderately worn. well separated by a deep groove. There is a spur on the entoconid. The parastylid is well developed extending the full width of the tooth throughout its height. There is an invagination in the floor of the metaflexid. The paralophid is pointed and has a small plication on its pos- terior border. The hypoconulid extends pos- teriorly with the hypostylid attached posteri- orly This material probably represents the same species as does that from either High Rock Can- yon or Virgin Valley Nevada. Downs (1961) summation of the characteristics of the known materials from the Nevada localities suggests that the Quartz Basin species is closer to the Virgin Valley form. Too little material is known of either to draw conclusions at this time. AP Tr AP Tr Protocone Protocone Tooth Tooth 19.5 19.8 19.2 19.7 18.9 20.2 19.7 21.6 21.6 22.2 21.1 4.0 2.8 20.0 20.6 4.6 2.5 20.6 20.2 4.6 2.6 20.3 20.8 18.0 18.4 17.4 18.4 3.7 2.6 18.1 18.9 4.5 2.8 17.3 15.9 22.2 18.5 17.1 4.9 3.3 18.7 17.8 6.0 3.6 18.7 4.5 2.8 17.5 15.2 18.6 17.5 MERYCHIPPUS sp. Three specimens from the Basque Cabin lo- cality, 2471, represent a species of Merychip- pus similar to M. sp. from Quartz Basin. The three specimens are all first or second upper molars. One is slightly worn, U020373, one is moderately worn, U020374, the other is in- complete and moderately worn, U020370. The slightly worn specimen has a height of crown of 31 mm, which is higher than any of the M. Figure 23. M erychippus sp. upper dentition, Quartz Basin, A P2 U019688 occlusal view, B labial view, C posterior view, D P3 UO 19698 occlusal view, E labial view, F anterior view, G M1 U019686 occlusal view, H labial view, I anterior view, J M2 U019685 occlusal view, K labial view, L anterior view, all x 1. -. 1968 SHOTWELL: MIOCENE MAMMALS 49 A B c D E F G H I J K L i so BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 seversus specimens from locality 2495 at Red Basin or from the Mascall as reported by Downs ( 1961). It is similar in height of crown to the Quartz Basin species. These specimens are also similar to the Quartz Basin species in the poorly developed anterior cingulum and reduced protoconal spur. In 0020374 the hy- poconal groove is open whereas in 0020373 it is invaded by two anti pli hypostyles. Assign- ment to the Quartz Basin species does not seem justified with so little material, but is probable: MERYCHIPPUS RELICTUS (Cope) (fig.24) This small rare species of M erychippus oc- curs in Quartz Basin at localities 2458, 2466, and 2467, in Oxbow Basin, locality 2431 and Kern Basin. No specimens from Red Basin are assigned to this species. A partial upper denti· tion including P2-M1 and an associated M1-M3 were recovered at locality 2467 in Quartz Basin. A similar upper dentition was recovered from Oxbow Basin, locality 2431. The other occurrences are of single specimens. The Quartz Basin specimens are unworn to only slightly worn whereas the Oxbow Basin ma- terial is moderately worn. The teeth are of about the same height of crown as those of M. seversus but are much smaller in their antero- posterior and transverse measurements. They are of about the same complexity as M. sever- sus. The protocone tends to be round to oval with a spur. All of the available specimens have a single pli caballin. A pli protoloph is present on the premolars. The anterior cingulum is only slightly developed. The crowns of the up· per premolars are not as strongly curved as in M. seversus. A mandible fragment (0019902) from lo- cality 2467, associated with the little worn upper dentition referred to above, includes the lower molar series. The parastylid of the M1 is strong and reflected in the occlusal pattern in early wear. On the M2 the upper portion of the parastylid is partially isolated as commonly seen in Hipparion. The metaconid and meta- stylid are damaged on M1 but on the M2 and Ma are present and separated by a deep groove. The lingual border is angular on both of these cusps. On the Ma the metaconid has a spur. The metaconid is slightly larger than the meta- stylid. The entoconid has no anterior spur on any of the molars. The hypoconulid and hypo- stylid form a triangular heel on the M2• On the Ma they form an open curved loph. The paraloph is attenuated. Cement is well devel- oped on all the teeth. Two isolated lower second premolars (0021818, 0019616) from local- ities 2462 and 2453 are referred to M. relictus. In these specimens the metaconid and meta- stylid are only partially separated. The para· lophid is broad distally. A spur is present on the entoconid of 0021818 but not on 00 19616. No hypostylid is present. The hypocon- ulid is small. There is a small plication on the anterior border of the entoflexid and a very small plicabellinid. There has been considerable question about the type locality of this species. Downs ( 1956) concluded that it is probably a Mascall locality. He arrived at this conclusion through a misin- terpretation of remarks attributed by Osborn to Merriam ( Osborn 1918) . Downs quotes Os- born as stating that Merriam believed the type material may have come from localities not far from the type area of the Mascall Formation. However, Osborn actually quoted Merriam as saying that the material may have come from outlying beds of the Mascall. This remark was apparently based only on the nature of the pres- ervation of the specimens. The material was collected by George C. Duncan of Silver Lake, Oregon and sent to Cope along with a few other specimens of various ages and representing Figure 24. Merychippus relictus, A P2•4 U024182 Oxbow Basin occlusal view, B P2•4 UO 19903 Quartz Basin occlusal view, C labial view, D Ma U019900 Quartz Ba- sin occlusal view, E labial view, F P2 UO 21818 Quartz Basin occlusal view, G labial view, H M1-a U019902 Quartz Basin dorsal view, I lateral view, J me- dial view, K upper incisor UO 19901 Quartz Basin labial view, L occlusal view, all x 1. 1968 SHOTWELL: MIOCENE MAMMALS 51 A H B I c - F D K L 52 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 TABLE 17 MEASUREMENTS OF UPPER PREMOLARS AND MOLARS M erychippus relictus Stage Height of Wear crown UOloc2467 U019904 P3 u 25.5 U019907 P3 u 26.8 U019908 P4 s 24.5 U019903 P4 s 24.9 UOloc2431 U024182 P3 M 20.6 U024182 P3 M 24.9 U024182 P4 M U024182 Ml M UOloc2466 U019900 M3 M 14.8 UOloc Kern Basin U024189 Ml U024190 M2 M 18.7a U-unworn, S-slightly worn, M-moderately worn. several types of preservation. No locality data other than "Oregon Desert" was available. It is not clear how the notation "?Idaho terrane" appeared in the description since it is not men- tioned by Cope in his original notice of the ma- terial (Cope 1889) in the American Naturalist but does appear in his American Philosophical Society paper (Cope 1889) of the same year. At that time Idaho was not a state but a terri- tory. It may be that Cope received additional data from Duncan but if so he doesn't mention it. Duncan was not a collector for Cope but a rancher and the postmaster at Silver Lake. It seems unlikely that he collected the material very far from his home area. It also seems un- likely that he collected it from an area where specimens of other species of M erychippus were abundant yet found none of them. There is no reason to believe that the type specimens came from the Mascall Formation in the John Day River Valley. Downs, with considerable reservation, assigned some specimens to M. relictus from the type area of the Mascall For- mation but considered them as integrading be- AP Tr AP Tr Protocone Protocone Tooth Tooth 16.8 16.7 16.8 16.6 4.4 2.8 17.0 16.6 4.8 2.3 16.9 16.4 4.0 2.8 15.9 4.1 2.8 16.0a 16.2 4.0 2.8 15.7 4.1 2.9 4.6 2.9 14.2 13.7 17.7 5.0 2.9 15.5 tween M. seversus and M. relictus. Several specimens from _the Crooked River area have been referred to M. relictus (Downs, 1956) and a specimen in the UOMNH from the same area is apparently M. relictus (U016993). The Barstovian: sediments in the Crooked River area or Paulina Basin are not now contiguous with the John Day Basin sediments although the se- quence there is similar to that of the John Day River Valley in the Picture Gorge-Dayville area. Thayer ( 1966) suggests that the original sheet of sediments was contiguous. The Paulina Basin is thirty miles southwest of the Mascall area. It is conceivable that Duncan's ranching activities may have brought him into that area, however, Barstovian sediments are also known east and south of Silver Lake. This discussion does not determine where the type locality of M. relictus may be, for with the discovery of a number of specimens in the Owyhee area in a stratigraphic unit which extends into Idaho and Copes reference to Idaho terrane the locality seems to be even more obscure. 1968 SHOTWELL : MIOCENE MAMMALS 53 A E Figure 25. Aphelops sp. Red Basin, A nasals U024135 dorsal view, B left lateral view, C anterior view, D premolar series U024135 left lateral view, E M3 U024160 occlusal view, all x 0.75. 54 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 SUBORDER CERATOMORPHA FAMILY RHINOCEROTIDAE APHELOPS sp. (Fig. 25) Locality 2493, produced a fragmental skull and lower jaw of a rhinocerotid (U024135) and a partial upper dentition of another indi- vidual (U024160) both badly damaged by frost heaving since they were near the surface. Additional teeth and tooth fragments occurred at both of these Red Basin localities. A crushed astragalus and tooth fragments were also found nearby at locality 2497. The upper den- tition is that of a subhypsodont form with rath- er simple teeth. The premolars are smaller than the molars and decrease markedly in antero- posterior measurement from P 4 to P2 • On the P 4 a cingulum closes off the transverse valley. It is otherwise much like the molars. Prominent anterior and posterior cingula are present on the upper molars. In late wear a post fossette is present on each of the molars except the M3 • A crochet is well developed on the M3 but does not close off the valley to form a medifossette. No crista is present on the upper molars. A small anti-crista is present on the first and second up- per molars. Aphelops from the Clarendonian Black Butte fauna (Shotwell & Russell 1963) is simliar in height of crown but has a more strongly developed crochet resulting in medi- fossettes in the upper molars. The fragmental skull includes the nasal bones. They are thick and relatively long and slightly pinched in at the ends. Rugosities near the tips indicate that a small horn was probably present. The specimens from locality 2495 in- clude a large upper incisor. It is well worn and has a short abruptly narrowing root. The crown is long and narrow as in Rhirwceros. A lower incisor tusk is also present. It is triangular in cross section at the point of occlusion and com- pares closely with that of Aphelops from the Black Butte fauna. The crushed astragalus compares with that of Aphelops in that the neck is not greatly shortened as in T eleoceras and the ginglimi are fully developed. Metapodial fragments indi- cate no expansion as seen in Teleoceras. The material is believed to represent a single species. The nasals were associated with upper molars, the same type of upper molars occur at the localities where the upper and lower in- cisors and the astragalus were collected. The joint occurrence of a nasal horn, upper incisors, and subhypsodont teeth suggests a mixture. Aphelops is believed to lack horns in most spe- cies as well as upper incisors but has subhypso- dont teeth. The characteristics displayed by this species, however, are found associated in the living species of Dicerhinos. The lack of upper incisors in Aphelops may not be as consistent as previously suggested. Very little of the known material includes the premaxillaries. In those few that do incisors are poorly devel- oped or absent. Some specimens also indicate a small nasal horn. The presence of a horn, elongate nasals, and upper incisors obviates an assignment to Peraceras. The best assignment thus seems to be to Aphelops. A B Figure 26. Prosthennops sp., mandible fragment with P4-M1 U022607 Quartz Basin, A side view, B occlusal view, both x 2. 1968 SHOTWELL: MIOCENE MAMMALS 55 ORDER ARTIODACTYLA SUBORDER SUIFORMES INFRAORDER SUINA FAMILY TAYASSUIDAE PROSTHENNOPS sp. (Fig. 26) A mandible fragment, 0022151, including P4-M1 is present in the collection from OOloc 2497, Red Basin. Specific assignment is not possible. From OOloc 2465, Quartz Basin a mandible fragment, 0022607, with P4-M1 is present plus several tooth fragments. Specific assignment is not possible with such limited material. INFRAORDER OREODONT A FAMILY MERYCOIDODONTIDAE Subfamily Ticholeptinae TICHOLEPTUS cf. OBLIQUIDENS (Cope) (Fig. 27) Ticholeptus is represented by upper and low- er dentitions; isolated teeth and partial denti- tions in the collection from OOloc 2497, Red Basin. A mandible fragment with the premo- lars occurred at OOloc 2495 also in Red Basin. A mandible, with left and right little worn dentition, from OOloc 2497, 0026798 best ex- hibits the characteristics of the lower dentition. The second and third premolars are crowded to the point that they overlap each other and the fourth premolar. They are relatively simple blade-like teeth. The Pa has a narrow proto- lophid. In the fourth premolar the protolophid connects to a metaconid which is narrow at the crest but broad at the base. It extends very little anterior to the protolophid but posteriorly it extends to the heel and joins the hypolophid forming an enclosed fossettid. The first pre- molar is blade-like tooth on 0026798, but on another specimen, 0023835, a mandible frag- ment with Pn with P 2 missing, the P1 is a large caniniform tooth. The other premolars present suggest that the two specimens represent the same species. 0023835 is of much older indi- vidual. In the lower molars a cingulum closes the intercrescentic valleys, but does not support a protostylid. The external ribs of the ectoloph are poorly developed. The stylids are present but not prominent. The ventral border of the mandible is rather straight and nearly parallel to the dorsal bor- der. A foramina is present at the base of the root of the P1. A maxilla, 0022192, from OOloc 2497 in- cludes P2-M3, alveoli of the canine and P1. The infraorbital foramen opens above the posterior root of the P3• The nasals are apparently not retracted judging from the character of the maxilla. The P2 and p a appear to have two broad roots while the P4 has three roots. The P2 and p a each have a strong protocone with an accessory cusp nearly as large and anterior to the protocone. The accessory cusp is connected to the parastyle by a loph from its anterior edge. It is also connected to the paracone by a loph arising from its crest. These two lophs form the boundaries of a small anterior fossette on the p a. Another loph connects the paracone and anterior border of the protocone forming an open lingual valley. The protocone is con- nected to the mesostyle by a posterior loph, which in the p a completes the encirclement of a posterior fossette. The P4 and molars all have a continuous lingual basal cingulum extending from the anterior face to the posterior face. The styles of the molars are very well developed. No external ribs are present on the ectoloph of any of the molars. Protostyles are not present. Published figures of Ticholeptus obliquidens reveal very little of the dental characteristics of the species. The form of the mandible, how- ever, compares closely with the Red Basin ma- terial. T. obliquidens was described from the Mascall Formation. Gazin ( 1932) assigned fragmentary material from Red Basin to Tich- oleptus? sp. Scharf ( 1935) in his study of the Sucker Creek fauna of the Owyhee region com- pared material from that fauna to T. petersoni but assigned it to Ticholeptus sp. At the same time he also examined the Skull Spring ma- terial from Red Basin and found that it also 56 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 A '·.~ B c Figure 27. Ticholeptus cf. obliquidens Red Basin, A left mandible U022798 dorsal view, B left lateral view, Cleft maxilla U022192 left lateral view, D ventral view, all x 1. 1968 SHOTWELL: MIOCENE MAMMALS 57 compared favorably with T. petersoni. Thorpe (1937) assigned the Skull Spring (Red Basin) specimens to Pronomotherium sp. and noted a similarity to P. siouense in the Pa Schultz and F alkenbach ( 1941) considered the same speci · mens to represent Ticholeptus. In this paper the authors considered T. petersoni to represent a subfamily other than the Ticholeptinae. In an earlier paper Schultz and Falkenbach (1940) had referred Pronomotherium siouense to the genus Brachycrus of the Merycochoerinae on the basis of identity and priority of name. Thus in the past the fragmentary Barstovian oreo- dont material from Oregon has been usually assigned to Ticholeptus but the species com- pared with are now to be found in three sepa- rate genera and subfamilies. None of the previ- ously known material revealed anything of the character of the skull. The present material indicates that the nasals were not retracted and that the infraorbital foramen was above a point between the pa and P4 • These are important characteristics of Ticholeptus as restricted by Schultz and Falkenbach (1941). The dental characteristics of Brachycrus siouense (=Pronomotherium) are indeed very close to those of the Red Basin specimen but so are those of T. hypsodus, for instance. Thorpe (1937) and Schultz and Falkenbach (1941) considered T. obliquidens and T. hypsodus to be very close. Schultz and Falkenbach (1941) considered T. zygomaticus to be close to T. hyp- sodus but with a slightly heavier and longer up- per and lower dentitions. Some authors have suggested that T. hypsodus and T. obliquidens are possibly synonymous. Thorpe (1937) at- tributed their similarities to parallism. If they are synonymous the name T. obliquidens has priority. If T. hypsodus and T. zygomaticus are. synonymous as well, then T. zygomaticus would prevail for all three of the species. For the present it seems best to refer the Red Basin specimens to T. obliquidens even though that species is not known well from its type locality. SUBORDER TYLOPODA FAMILY CAMELIDAE Camelid Wildcat Creek UOloc 2345, Red Basin UOloc 2495, Quartz Basin localities 2456, 2461, 2462, and Basque Cabin UOloc 2471 have all produced foot elements of a small camelid. The elements consist of a number of scaphoids, unciforms, fragmental metapodials, two astragali and a single phalanx. None of the material is such that a specific assignment could be made. The most than can be said is that a small camelid is sparsely represented at the above localities. SUBORDER RUMINANTIA INFRAORDER PECORA SUPERFAMILY CERVOIDEA FAMILY CERVIDAE Subfamily Paleomerycinae DROMOMERYX BOREALIS Douglas 1909 (Fig. 29-31) Dromomeryx near borealis Gazin 1932, Carn. Inst. Wash. Pub. No. 418, p. 82 Rakomeryx gazini Frick 1937, Bull. Amer. Mus. Nat. Hist., Vol. 69, p. 106 Dromomeryx is one of the most abundant large mammals at UOloc 2495 in the Red Ba- sin. it occurs also at other localities but not so abundantly. Nearly all elements of the skeleton are present and are described below. MANDIBLE: The mandible is curved, dorso- ventrally but not so strongly as in Dama. The angle of the jaw is similar to Cervus in that it lacks the angular process present in Dama. The depth of the jaw is about the same as in Cervus. The coronoid process is not complete on any of the specimens but the most complete example indicates that it is much straighter than in liv- ing cervids and not curved strongly posteriorly although it may be curved at the distal end. The notch between the coronoid process and the condyle is broad. The diastema is considerably longer than in Dama or Cervus. It is fifty five 58 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 external ribs A ant j Pal Hyl B Figure 28. Dental nomenclature used on Artiodac- tyl teeth. A upper molar Hy-Hypocone Pac-Paracone Hys-Hypostyle Pas-Parastyle Mel-Metaloph Pr-Protocone Mess-Mesostyle Prl-Protoloph Met-Metacone Prs-Protostyle Mets-Metastyle B lower premolar Ent-Ectolophid Pal-Paralophid Hy-Hypoconid Prc-Paraconid Hyl-Hypolophid Prl-Protolophid Me-Metaconid Prs-Protostylid Mets-Metastylid percent of the total tooth row length ( 83-90 mm). There is a large mental foramen opposite the posterior border of the symphysis. Another, but much smaller, mental foramen appears be- low the P 2 with an additional small foramen situated about half way between the others on some specimens. The mandibular foramen is about in line with the occlusal surface of the cheek teeth. LOWER DENTITION: The incisiform teeth in- clude the three incisors and the incisiform ca- nine. Their relative sizes and morphology com- pare closely with those of Dama. There is a strong rib developed on the inner face of each of the incisiform teeth. It is located closest to the posterior edge of the tooth. · The teeth de- crease in size from 11-C. An alveolus for the first premolar is present on several mandibles of mature individuals and also on young individuals still possessing ele- ments of the deciduous dentition. No mandibles of old individuals have an alveolus for the first premolar. In no instance is a DP1 or a P1 pre- served. It is not clear whether this species had only a DP1, retained much later in life than the other elements of the deciduous dentition, or whether both deciduous and permanent first premolars were present with the permanent first premolar lost before old age as is the case in some other ungulates. The P 2 is the smallest and simplest tooth of the lower dentition. Lophids are not as well de- veloped as in Dama but more so than in Cervus. The protolophid is essentially absent since the metaconid, which is very broad at its base, meets the labial side of the tooth at the crest. The paralophid is very narrow. The hypolo- phid and ectolophid are well developed but low. The Pa is much larger than the P2. The para- lophid is branched lingually forming a small open valley. The protolophid terminates in the metaconid which is very narrow at its crests but broad, antero-posteriorly, at its base. The hypo- lophid and ectolophid join lingually forming a small enclosed fossette. An accessory lophid extends into this fossette from the hypolophid. A broad but short accessory lophid extends into the anterior valley. The highest point on the tooth is the protoconid. Although the P4 is usually slightly larger than the P 3 it is similar in many of its charac- teristics. Its primary feature is the anterior- posteriorly enlarged metaconid which closes off the anterior valley between the protolophid and posterior branch of the paralophid. The P 4 1968 SHOTWELL: MIOCENE MAMMALS 59 A B Figure 29. Dromomeryx borealis, Red Basin, lower incisors UO 22119, A ventral view, B dorsal view, both x 0.75. is broader than the P 3 • The development of the tooth is similar to that of Dama but lacks the protostylid and metastylid seen in deer. The lower molars all possess a protostylid and the Paleomeryx fold. The enamel of all the cheek teeth is crenulated. Anterior and posteri- or cingula are present on all the molars. The anterior cingula is the stronger. The ratios of individual tooth lengths to total tooth row length are as in Dama hemionus co- lumbiana. In seven complete lower cheek tooth series the premolars average sixty five percent of the molars in length, ranging from sixty one to sixty nine. This is similar to that of living cervids. UPPER DENTITION: The P2 is triangular in oc- clusal outline with three roots. The anterior- posterior diameter is greater than the trans- verse. The protoloph is well developed. It ter- minates labially in a parastyle and lingually at the protocone. The protocone is a prominent feature of the tooth. Small weakly developed cingula occur on both anterior and posterior sides of the protocone. A complete posteroloph connects the protocone to the ectoloph. A small accessory loph connects from the protocone to a point on the posteroloph about one third of its length posterior to the protocone. A small fossette is thus formed. The paracone is mas- sive and the highest cusp of the tooth. Its labial surface has a strong style present. The P3 is similar to the P 2 in basic pattern. It is broader transversely so that the anterior- posterior and transverse diameters are equal. The cingula of the protocone are much more strongly developed than in the P2 • It is only slightly larger than the P2 • The basic pattern of the P4 is as in the other premolars, however, the protocone is much more prominent and the transverse diameter of the tooth is much greater than the anterior- posterior diameter. The cingula bordering the protocone are very strongly developed. The upper molars are similar to each other but increase in size antero-posteriorly, the first -being the smallest. In the upper molars the antero-posterior diameter is nearly the same as the transverse. The ectoloph of each of the up- per molars exhibits a parastyle, a broad exter- nal rib labial to the paracone, a mesostyle, a strong but narrow external rib labial to the metacone and a metastyle which often appears forked in occlusal outline. The protoloph con- nects high on the parastyle. The metaloph does not connect to the ectoloph. The anterior cres- cent is completed posterior to the protocone by a large irregularly shaped crochet which con- nects in some specimens to the protocone, in others to the metaloph, and often to both. A small fossette is often formed between the ir- regularities in the crochet and the metaloph connection. The posterior crescent is completed by a structure similar to the hypostyle of equids, however, it does not quite connect to the metastyle in some specimens. The hypostyle is often branched and sometimes has several branches. A well developed anterior cingulum is present on all the upper molars. A much less strongly developed posterior cingulum is also present. A protostyle is present on each of the molars. 60 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No. 14 u 1968 SHOTWELL: MIOCENE MAMMALS 61 A number of specimens have cement present on the teeth. It is only recognized on the labial and lingual faces, extending into the open val- leys between cusps. It does not occur in the fossettes of any of the specimens. FOREFOOT: The radial facet of the scaphoid is similar to that of Dama but broader ventrally. The scaphoid lacks the strong medial protuber- ance present on Cervus. Its manubrium facet is similar to that of Cervus, not broad as in Dama. The radial facet of the lunar has somewhat less relief than that of Cervus or Dama and is more elongate. The articulation with the magnum is similar to both Cervus and Dama. The scaphoid and cuneiform facets are comparable with Dama. The only cuneiform present is distorted to the extent that comparisons are of little val- ue. The pisiform is elongate as in Dama and is curved slightly dorso-ventrally. There is a heavy rough ridge running from the anterior end of the cuneiform facet to the distal end of the pisiform. The cuneiform facet is long and ovoid in shape as in Cervus rather than broad as in Dama. The facet is not so strongly curved antero-posteiorly as in Cervus. The magnum is very close to Cervus and if it were not for the difference in size in the two animals might be mistaken for Cervus. The dorsal unciform facet is nearly square as in Cervus not rectangular as in Dama. The ventral unciform facets differ from both Cervus and Dama in that they are round. The unciform is also close to that of Cervus. It differs primarily in the facets for the magnum which are essentially mirror images of the unciform facets of the magnum. None of the metacarpal fragments are complete enough to provide useful comparative data. HINDFOOT: The navicular-cuboid groove of the astragalus is similar to that of Cervus in that the medial side is not strongly convex at it bor- der. The lateral ginglymus has a greater dia- meter than does the medial one as in Cervus Figure 30. Dromomeryx borealis, Red Basin, A P2-M3 U023705 occlusal view, B right mandible U023393 lateral view, C dor- sal view, all x 0.75. rather than in Dama. The calcaneum is close to that of Cervzts in most characteristics. The fib- ular facet is much more expanded medially in Cervus than it is in Dromomeryx which is more like Dama in this respect. The astragalus and calcaneum facets of the navicular-cuboid are more similar to those of Dama than Cervus. The ventral protuberance of the navicular portion is low on Dromomeryx, even lower than in Dama. The foramen between the navicular and cuboid portion opens into a well defined groove which extends in a curve through the gap be- tween the ventral protuberances of the articular surface. In Dama and Cervus the foramen is isolated from the interprotuberance groove. The articular facet for the calcaneum is similar to that in Dama. The meso-cuneiform and meta- tarsal facets of the navicular-cuboid are nearly parallel in Dromomeryx somewhat as in Cervus rather than diverging as in Dama. The metatar- sal facets are only slightly separated by a slight ridge in Dromomeryx. The ventral facet of the two is a continuation of the form of the dorsal facet. In Dama and Cervus the ventral facet is separated by a deep groove. It is long and nar- row, oriented transversely. The mesocuneiform facet is more rectangular in outline than in either Dama or Cervus. Of the foot elements studied the navicular-cuboid is least like Dama or Cervus. The mesocuneiform is rectangular in outline. A small facet is present on its lateral side. This facet articulates with a matching facet on the cuboid portion of the navicular- cuboid. In Cervus this articulation is accom- plished by a curved proximal surface on the mesocuneiform. In Dama this articulation ap- parently does not occur. One metatarsal present in the collection is complete enough to indicate its length but is so fractured that little else is clear. It is elongated to the same degree as in Dama and Cervus. A well defined dorsal groove is present. Less com- plete specimens indicate that this groove termi- nates at its distal end in a large foramen. Lat- eral metatarsals or metacarpals are not present in the collection. The phalanges are nearly all crushed so that assignment and description are 62 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 A ( - -...... ,,.;~/ ('/ \ . - ~.:::_ ~ ~ · -:,-·,,..;™"- B Figure 31 Dromomeryx borealis, Quartz Basin, right mandible P4-M2 U019273, A occlusal view, B lateral view, both x 0.75. not possible. They appear to be of the same pro- portions as those of Cervus. SKULL: Two badly crushed skulls are present in the collection from Red Basin. One, UO 22219, is crushed antero-posteriorly. The horn pedicles are complete but flattened by the crush- ing. The other, U023705, is crushed laterally. The horn pedicles are broken off at about one third their length above the skull. The portion of the skull anterior to the P2 is missing. De- tails of the skull are largely destroyed by the crushing. The horn pedicles are about 240 mm long. A lateral flange is present. They appear to have been directed forward, however it is not possible to determine to what degree. The rec- ognition of facial vacuities is not possible due to the shattered and distorted nature of that part of the skull. DISCUSSION: The Red Basin specimens agree in size with D. borealis. The upper teeth are com- plicated by spurs in the same way as those of D. borealis. The lower dentition of D. borealis was described by Douglas (1909) and illus- trated. The P 4 differs from most specimens of the Red Basin species in that the metaconid closes off the valley between the protolophid and entolophid. This only occurs rarely in the Red Basin material. Frick (1937) assigned previously collected Red Basin specimens to Rakomeryx gazini. Gazin had earlier (1932) described these specimens and assigned them D. near borealis. The assignment by Frick was based on what he considered to be peculiarities of the horn core. The proportional size of the premolars, the en- larged metaconid on the P 4 , and the gross size all strongly favor the assignment of Dromo- meryx. The differences between the Red Basin specimens and D. borealis are so slight that there seems to be no real basis for separation. The name Rakomeryx gazini is thus not ap- plicable. RAKOMERYX cf. AMERICANUS (Douglas 1909) (Fig. 32) Two fragmentary mandibles are present representing a small paleomerycid in the Red Ba~in collection. Neither is complete enough to indicate the length of the diastema or the character of the ascending ramus. The relative depth of the jaw appears to be about the same as that of Dromomeryx. A large mental fora- men occurs below and anterior to the P 2• The P 2 is the smallest tooth of the cheek tooth series. 1968 SHOTWELL: MIOCENE MAMMALS The protolophid plus the protoconid and meta- conid form a single large cusp which dominates the tooth pattern. The paralophid is small and simple. The ectolophid and hypolophid are well developed but low. The P3 is larger than the P 2 but similar in most characteristics, how- ever the paralophid is much better developed and branched. The protolophid is more distinct than in the P 2• The P 4 is the largest tooth of the premolar series. It differs from the other pre- molars in the presence of a distinct metaconid well attached to the protolophid. The meta- conid is, however, not greatly expanded antero- posteiorly and does not close off the anterior or posterior valley as it does in Dromomeryx. All the lower molars have the Paleomeryx fold, a protostylid and an anterior cingulum. External ribs are present on the ectolophs. The enamel of the molars is crenulated. The upper premolars are all three rooted. The ectoloph of each premolar includes a low parastyle, a strong external rib and a high meta- style. The paracone is the highest cusp. The protocone is prominent and is connected to the parastyle anteriorly and the metastyle posteri- orly by narrow lophids. Accessory lophids oc- cur posterior to the protocone and on some specimens form enclosed fossettids against the posterior lophid. Cingula are absent or only very poorly developed. The premolars become proportionately broader transversely from P2- P4. The molars increase in size from M1-M3 • The ectoloph includes parastyle, external ribs, mesostyle, and metastyle. An anterior cingula occurs on all the molars. Each molar displays a protostylid. The protoloph connects to the ectoloph at the parastyle. The metaloph does not reach the ectoloph. Small crochets are pres- ent but are not as well developed as those of Dromomeryx borealis. The astragalus is the size of Dama ( colum- biana). The ginglymi are more nearly the same Figure 32. Rakomeryx cf. americanus, Red Basin, A left P2-M1 U022147 medial view, B dorsal view, C lateral view, D P 4-M3 UO 22089 occlusal view, E r 2.a U022089 occlusal view, all x 0.75. 63 A B c D E 64 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 TABLE 18 ANTERIOR POSTERIOR AND TRANSVERSE DIAMETERS OF THE DENTITION OF Rakomeryx americanus U022146 U022147 U022141 9.8 4.3 8.8 4.8 12.4 6.3 12.9 6.4 13.0 7.8 13.2 7.9 12.5 9.8 34.7 34.9 p2 U022089 11.9 9.1 pa 12.4 10.7 p4 10.a 15.0 Ml 13a 17.0a M2 15a 18.2 24.7 11.4 Ma 16.4 18a diameter as in Dama than in Dromomeryx bo- realis. The borders of the navicular-cuboid groove are similar to those of Dama. The cal- caneum is very close to Dama in size and most other characteristics. The fibular facet is dis- tally rounded as in Cervus whereas in Dama it ends abruptly. The mesocuneiform is the size of that of Dama but with the lateral articulation seen in Dromomeryx borealis. The unciform is the size of that of Dama ( Columbia Mule Deer) buts its characteristics are as in Dromomeryx. The low crowned teeth, Paleomeryx fold, cingula, stylids and generally deer-like charac- teristics of this species indicate that it is prob- ably a member of the Dromomerycinae. The lack of enlargement of the metaconid on the P 4 thus retaining the premolar aspect of that tooth suggests that this species belongs in the genus Rakomeryx. Horn cores are not present in the available material so that assignment cannot be based on them. This species is much smaller than Dromomeryx from the same site and dif- fers in not only size but in molarization of the P 4 and complexity of the upper dentition. Frick (1937) has assigned the name Rakomeryx gazirti to specimens reported by Gazin ( 1932) . The type and referred specimens are from Red Basin and represent the larger of the two drom- omerycines described here. The assignment of the species R. gazini· to Dromomeryx gazini is discussed under the description of that ma- terial. The small species discussed here cannot be assigned to R. gazini. The species described here is much larger than Blastomeryx mollis from Virgin Valley Nevada. Specimens of the Skull Spring fauna assigned to Blastomeryx? sp. by Gazin ( 1932), a D P4 and an upper molar, are larger than Blastomeryx mollis and apparently represent the small dromomerycine described here. The lack of molarization of the P 4 in this species is similar to both Blastomeryx and Rakomeryx. The size is close to that of Rakomeryx raki. The lophs of the upper premolars are complete and attached to the ectoloph in the Red Basin spe- cies whereas they are interrupted in R. raki as illustrated (Frick 1937). The metaconid of the P 4 of R. raki is more anterio-posteriorly elongate than in the new species. Although the several dentitions illustrated of R. raki indicate variation in this characteristic. Dromomeryx? americanus as illustrated by Douglas (1909) is very close to this new material and close to it in size. Frick 1937 assigned D? americanus to ? Bouromeryx. The specimens described by Douglas and the new material appear close. I am assigning them here to Rakomeryx ameri- canus (Douglas) . SUPERFAMILY BOVOIDEA FAMILY ANTILOCAPRIDAE MERYCODUS sp. (Fig. 33 A, B) Red Basin localities 2495 and 2497 have produced incomplete upper and lower denti- tions, isolated teeth and fragments of skeletal elements of Merycodus. No horn core speci- mens were recovered. An upper dentition, UO 22215, from locality 2497 and a partial lower dentition, U022150, from the same locality best illustrate the characteristics of this form. The lower second and third molars have ac- 1968 SHOTWELL: MIOCENE MAMMALS cessory pillarlike cusps between the crescents of the teeth. In the upper dentition P2-P4 are three rooted. On the molars a small accessory fossette occurs at the head of the intercrescentic valley. MERYCODUS cf. NEV ADENSUS (Fig. 33 C-F) A small species of Merycodus is represented at locality 2465, Quartz Basin, by a large por- tion of the upper dentition, probably of a single individual, a partial horn core, and a fragmen- tal metapodial. The lack of lower dental ele- ments makes comparison with other species difficult. The horn core is compressed on its medial side so that the cross-sectional outline is roughly triangular. No evidence of a burr is present. The horn core fragment is unbranched and is 105 mm long above the base. A small fragment present in the collection indicates that the horn core of this species is branched but the tines are very short. In the upper dentition the premolars are three-rooted. An intercresentic accessory fos- sette occurs at the head of the valley in the M1 • On all of the upper molars there occurs an ac- cessory fossette at the anterior end of the pos- terior fossette just inside the mesostyle. The Quartz Basin species is apparently smaller than the Red Basin material. In size and comparable characteristics the Quartz Basin species is sim- ilar to M. nevadensus. ?MERYCODUS sp. An ectoloph fragment of a Merycodus-like upper molar present in the collection from UOloc 2465, Quartz Basin, represents a much larger species than M. nevadensis. Converging styles on a high crowned tooth suggest a species of merycodont. Figure 33. A Merycodus sp. Red Basin, right P3-M3 lateral view x 1, B occlusal view, C Merycodus cf. nevadensis Quartz Ba- sin, left P3-M3 U019757 occlusal view, D right M1'2 U019757 lateral view x 2, E ventral view x 2, F horn core UO 19744 x 1. c D E A B F 65 .I . I j' tl' j .. 1 , ( ,, ti' 1/ . . ~ c i I, I. ; l I!, . tr r1 .t 1jl I/ 66 BULLETIN, MUSEUM OF NATURAL HISTORY, UNIVERSITY OF OREGON No.14 REFERENCES CITED Black, C. C., 1963, A review of the North American Tertiary Sciuridae: Bull. Mus. Comp. Zool. v. 130, no. 3, pp. 111-248. Bode, F. D., 1934, Tooth characters of protohippine horses with special reference to species from the M erychippus zone, California: Carn. Inst. Wash. contr. Paleo. 453, pp. 39-63. -----, 1935, The fauna of the Merychippus zone, North Coalinga district, California: Carn. Inst. Wash. Cont. Paleo. 453, pp. 65-96. Bryant, M. D., 1945, Phylogeny of Nearctic Sciur- dae; Amer. Mid. Nat., v. 33, no. 2, pp. 257-390. Butler, P. M., 1947, On the evolution of the skull and teeth in the Erinaceidae, with special refer- ence to fossil material in the British Museum: Proc. Zool. Soc. London, 118: 446-500. Condon, Thomas, 1896, Scientific description of two new fossil dogs; Bull. Univ. Oreg., v. 2, no. 6, p. 11. Cope, E. 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Mam- mal., v. 12, pp. 156-158. ----, and Keith R. Kelson, 1959, The mam- mals of North America; Ronald Press, New York. Hutchison, J. H., 1964, Late Tertiary Insectivores of the Northern Great Basin: Univ. Oreg. Masters thesis. -----, 1966, Notes on some Upper Miocene Shrews from Oregon: Bull. no. 2, U. 0. Mus. Nat. Hist., 23 pp. -----, 1968, Fossil Talpidae (Insectivora, Mammalia) from the later Tertiary of Oregon; Bull. no. 11, U. 0. Mus. Nat. Hist., 117 pp. James, G. T., 1963, Paleontology and Nonmarine Stratigraphy of the Cuyama Valley Badlands, Cali- fornia Pt. 1: Univ. Calif. Pub. Geol. Sci. v. 45, pp. 1-154. Kittleman, L. R., 1965, Cenozoic stratigraphy of the Owyhee region, Southeastern Oregon; Bull. no. 1, Mus. Nat. Hist. Univ. Oreg., 45 pp. 1968 SHOTWELL: MIOCENE MAMMALS 67 -----, 1967, Geologic map of the Owyhee re- gion; Bull. no. 8, Mus. Nat. Hist. Univ. Oreg. Li, C., 1962, A Tertiary beaver from Changpei, Hopei Province: Vert. Palas., v. 6, no. 1, pp. 72-77. -----, 1963, A new species of Monosaulax from Tung Gur Miocene, Inner Mongolia: Vert. Palas., v. 7, no. 3, pp. 240-243. Matthew, W. D., 1924, Third contribution to the Snake Creek fauna: Bull. Amer. Mus. Nat. Hist., v. 50, pp. 59-210. McGrew, P. 0., 1939, A new Amphicyon from the Deep River Miocene: Field Mus. Nat. Hist., Geo. Ser. v. 6, no. 23, pp. 341-350. Merriam, J. C., 1911, Tertiary mammal beds of Virgin Valley and Thousand Creek in Northwest- ern Nevada; Univ. Calif. Puhl. Bull. Dept. of Geol. v. 6, no. 11, pp. 199-304. Olsen, S. J., 1960, The fossil carnivore Amphicyon longiramus from the Thomas Farm Miocene: Bull. Mus. Comp. Zool. v. 123, no. 1, pp. 1-44. Osborn, H.F., 1918, Equidae of the Oligocene, Mio- cene, and Pliocene of North America; icono- graphic type revision: Mem. Amer. Mus. Nat. Hist., no. 2, pp. 1-330. Reed, C. A., and T. Downs, 1958, A fossorial mam- mal of unknown affinities from the Middle Miocene fauna of Nevada: J . Mammal. v. 39, pp. 87-91. Scharf, D. W., 1935, A Miocene mammalian fauna from Sucker Creek, Southeastern Oregon: Carn. Inst. Wash. Contr. Paleo. 453, pp. 97-118. Schultz, C. B. and C.H. Falkenbach, 1940, Mery- cochoerinae: Bull. Amer. Mus. Nat. Hist. v. 77, Art. 5, pp. 213-306. -----, 1941, Ticholeptinae: Bull. Amer. Mus. Nat. Hist., v. 79, Art. 1, pp. 1-105. Shotwell, J. A., 1958, Evolution and Biogeography of the Aplodontid and Mylagaulid Rodents: Evo- lution v. 12, no. 4, pp. 451-484. -----, 1961, Late Tertiary Biogeography of Horses in the Northern Great Basin: ]our. Paleo. v. 35, no. 1, pp. 203-217. -----, 1963, The Juntura Basin: studies in earth history and paleoecology; Amer. Philos. Soc. n.s. v. 53, part 1, pp. 1-77. -----, 1967 A Peromyscus of the Late Tertiary in Oregon; Bull. no. 5, Mus. Nat. Hist. Univ. Oreg. 35pp. -----, 1967B, Late Tertiary geomyoid rodents of Oregon; Bull. no. 9, Mus. Nat. Hist. Univ. Oreg. 50pp. Stirton, R. A., 1935, A review of the Tertiary heav- ers: Univ. Calif. Pub. Bull. Dept. Geol. Sci. v. 23, no. 13, pp. 391-458. -----, 1947, Observations on evolutionary rates in hypsodonty; Evol., v. l, pp. 32-41. Thayer, T. P. and C. E. Brown, 1966, Local thickening of Basalts and late Tertiary silicic vul- canism in the Canyon City Quadrangle, north- eastern Oregon; USGS Prof. Paper 550-C, pp. C73-C78. Thorpe, M. R., 1937, The Merycoidodontidae: Mem. Peabody Mus., no. 3, pp. 1-428. Wallace, R. E., 1946, A Miocene mammalian fauna from Beatty Buttes, Oregon; Cam. Inst. Wash. Puhl. 551, pp. 113-134. Webb, S. D., 1961, The first American record of Lant,anotherium Filhol; Jour. Pal. v. 35, no. 5, pp. 1085-1087. Wilson, R. L., 1965, Techniques and materials used in the preparation of vertebrate fossils; Curator, v. 8, no. 2, pp. 135-143. Wilson, R. W., 1960, Early Miocene Rodents and insectivores from Northeastern Colorado: Univ. Kan. Paleo. Cont., Art. 7, pp. 1-92. Wood, A. E., 1962, The early Tertiary rodents of the family Paramyidae; Trans. Amer. Philos. Soc., n.s., v. 52, pt. 1, pp. 3-261. PUBLICATIONS Museum of Natural History University of Oregon Eugene, Oregon Bulletins Titles Price No. 1 Cenozoic Stratigraphy of the Owyhee Region, Southeastern Oregon; Kittle- man, L. R. et al., 45 pp., 9 plates 11 figures, (December 1965) $1.50 No. 2 Notes on some Upper Miocene Shrews from Oregon, Hutchison, J. H., 23 pp., 17 figures, (March 1966) $1.25 No. 3 A New Archaic Cetacean from the Oligocene of Northwest Oregon, Emlong, D., 51 pp., 15 figures, (October 1966) $1.50 No. 4 The Archaeology of a Late Prehistoric Village in Northwestern California; Leonhardy, Frank C., 41 pp., 17 figures, (March 1967) $1.00 No. 5 Peromyscus of the Late Tertiary in Oregon; Shotwell, J. Arnold, 35 pp., 11 figures, (June 1967) $1.25 No. 6 Ethnomalocology and Paleoecology of the Round Butte Archaeological Sites, Deschutes River Basin, Oregon; Roscoe, E., 20 pp., 4 figures (July 1967) $ .75 No. 7 Its Own Story, The Museum of Natural History; 16 pp. no charge No. 8 Geologic Map of the Owyhee Region, Malheur County, Oregon; Kittleman, L., and others, scale 1 :125,000 (September 1967) $2.00 No. 9 Late Tertiary Geomyoid rodents of Oregon; Shotwell, J. Arnold, 28 figures (November 1967) $1.25 No.10 Refinements in Computerized Item Seriation; Craytor, W.B., and LeRoy Johnson Jr., (March 1968) $ .75 No.11 Fossil Talpidae (lnsectivora, Mammalia) from the Tertiary of Oregon; Hutchison, J. $1.25 No. 12 Plants of the Three Sisters Region, Oregon Cascade Range; Ireland, 0. 130 pp. $3.75 No. 13 Historical Background of the Flora of the Pacific Northwest; Detling, LeRoy (July 1968) $1.50 No. 14 Miocene Mammals of Southeast Oregon; Shotwell, J. A. $1.25 Cover Photo{?raph by Bernard Freemesser