Bering, N., T. Hext and E. Parker. 2017. Nucella ostrina. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR. Taxonomy: Nucella was previously called Thais. Thais is now reserved for subtropical and tropical species. For a more detailed review of gastropod taxonomy, see Keen and Coan (1974) and McLean (2007). Nucella. ostrina has mistakenly been called N. emarginata though it has now been found that the two species diverged in the late Pleistocene epoch (Marko et al. 2003) Description Size: Rarely over 30 mm (Kozloff 1974), usually up to 20 mm (Puget Sound); up to 40 mm, but rarely over 30 mm (California) (Abbott and Haderlie 1980); illustrated specimen (Coos Bay) 20 mm. Females slightly larger than males (average 18.9 and 17.8) (Houston 1971). Color: Exterior brown and dingy white, dirty gray, yellow or almost black (if diet of mussels); yellow, black or gray periostracum in grooves between ridges; ridges sometimes white (black in this specimen). Interior: aperture and columella chestnut brown or purple. Shell Shape: Fusiform; short spire, expanded whorl. Shell thin, not heavy. 3-4 whorls; nuclear whorl inconspicuous. Sculpture: Spire relatively high, partial nub of aperture lacking (McLean 2007); alternating large and small spiral ridges over most of shell, can be nodulose; sometimes ridges are obscure and surface is fairly smooth. Axial sculpture wrinkled, not prominent. Outer Lip: Thin, crenulate, not thick and layered (Oldroyd 1924). No denticles or anal notch on posterior (upper) end, no single strong tooth near anterior canal. No row(s) or denticles within lip. Columella: Sunken and concave, arched and flattened below: species ostrina; no folds, (Fig. 1). Sutures: Not deep (Fig. 1). Anterior (Siphonal) Canal: Short: less than 1/4 aperture length: species ostrina (Kozloff 1974) (Fig. 1); canal narrow, slot-like, not spout-like; not separated from large whorl by revolving groove. Aperture: Wide; length more than 1/2 shell length (Oldroyd 1924). Ovate in outline, with a short anterior canal but no posterior notch (Fig. 1). Umbilicus: Closed (McLean 2007). Operculum: Dark brown with nucleus on one side (Fig. 2). Eggs: Pale yellow, vase-shaped, about 6 mm high, in clusters of up to 300 capsules (Abbott and Haderlie 1980) (Fig. 4). Each capsule with 500-600 eggs. Each capsule with a longitudinal suture and a hard clear escape aperture. Veliger: Four distinct stages: advanced shell measures 775µ long (LeBoeuf 1971) (Fig. 5). Possible Misidentifications Snails of the genus Nucella can be distinguished from other carnivorous estuarine gastropods by their sculpture (the same on both spire and whorls), by the large body whorl and by the large ovate aperture. Other genera with a siphonal notch, and generally fusiform shape include: Olivella and Buccinum, which have columellar folds; Ocenebra and Ceratostoma which have a spout-like siphonal canal, not a narrow-slot- like one as in Nucella; Tritia reticulata and Lirabuccinum dirum which have a distinct revolving furrow or fossa setting off the anterior canal from the body whorl; (Lirabuccinum has spiral sculpture only on the body whorl; the spire has both spiral and axial ribs); Nucella ostrina Phylum: Mollusca Class: Gastropoda, Prosobranchia Order: Neogastropoda Family: Thaisidae The rock-dwelling emarginated dogwinkle A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12914 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: oimbref@uoregon.edu Bering, N., T. Hext and E. Parker. 2017. Nucella ostrina. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR. Acanthina (also from the family Thaisidae), which has a strong tooth on the anterior end of the outer lip. There are three other species of Nucella in our area. Two are not typically found in estuarine conditions, but they do look quite a bit like N. ostrina: Nucella lima, the file dogwinkle, is subtidal, short-spired, and fairly rare. It is whitish to brown, with about 15 alternating large and small file-like spiral ridges on the large whorl. It can be up to 43 mm, somewhat larger than N. ostrina. Nucella canaliculata, the channeled dogwhelk, has a high spire and a prominent shoulder below the deep suture. It is light (white to orange), and sometimes banded. Its 14-16 spiral ridges are very evenly shaped and spaced. It is an inhabitant of outer shore mussel beds. Larger than N. ostrina, it averages 26.5 mm (male) and 24.8 mm (female) (California) (Houston 1971). The third species, Nucella lamellosa (see description in this guide), is the most common dogwinkle in the northwest, quite common in bays and estuaries, and one of its many variations is very like N. ostrina. N. lamellosa can have strong axial ruffles, be quite smooth, or have strong horizontal ribs. In this last case, it is difficult to distinguish from N. ostrina. N. lamellosa has a higher spire (usually 5-7 whorls, including the tiny nuclear whorl); it is heavy, with a thick-layered lip, not a thin crenulated one. There is usually at least one row of denticles inside the lip in N. lamellosa; its anterior canal is longer than that of N. ostrina (more than 1/4 aperture length). While N. lamellosa can have strong spiral ridges, the body whorl in this species is then often flattened and angled, not expanded as in N. ostrina, and the horizontal ridges themselves are not alternating large and small (compare Fig. 2, N. lamellosa in this guide). Nucella lamellosa inhabits much quieter waters, as a rule, and a lower tidal range than does N. ostrina. Its color is usually lighter; it is rarely blackish. A fourth species of Nucella, Nucella emarginata though not found in our area can easily be confused with N. ostrina because they are morphologically cryptic. See Marko et al. (2003) for a more detailed discussion. Ecological Information Range: Bering Sea south to northern Baja California, but rare below Pt. Conception (Abbott and Haderlie 1980). Local Distribution: Coos Bay: marine portions, i.e. near bay mouth up to Fossil Point. Habitat: Almost entirely on rocky shores; in fairly heavy surf (Ricketts and Calvin 1971); also in semi-protected areas (Houston 1971). Outer shores in mussel beds, on jetties. Salinity: Full seawater; collected at 30. Temperature: Cold to temperate waters: small animals high in tidal range show great thermal resistance, active at range of 0-30°C (Bertness and Schneider 1976). Tidal Level: Ubiquitous intertidal predators, found from mid to high intertidal zones (Moran and Emlet 2001). Associates: Primary prey is barnacles, especially Balanus; mussel Mytilus; Pisaster ochraceus. Commensal flatworm Nexilis epichitonius found in specimens on Coos Bay entrance jetty (Holliman and Hand 1962). Weight: 1.5 gm (wet). Abundance: Common to abundant (McLean 2007); much less common in inner bay than N. lamellosa (Coos Bay). Life History Information Reproduction: Found to spawn year-round in Bodega Bay, Calif. and throughout Oregon, but most activity is in November-February. Little hermaphroditism (Houston 1971). Spawning is not salinity, photoperiod or temperature-related (Houston 1971). Females gregarious (groups to 20), deposit egg capsules in clusters. Each female lays 8-9 capsules; stalked capsules have about 200- 300 eggs each (ibid), many of which may be sterile nurse eggs which are consumed by developing larvae. Veligers swim in capsule fluid and metamorphose into snails about 1.1 mm long, emerging from plug at top of capsule (ibid). Pacific Northwest hatchlings number about 10-20 per capsule average; Bodega Bay about 5% hatch (10-15) (ibid). A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12914 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: oimbref@uoregon.edu Growth Rate: Pacific Northwest: 2.5-3 months from egg deposition to hatching; possibly more rapid development farther south (Abbott and Haderlie 1980). Longevity: 5-10 years (Dawson et al. 2014). Food: Prefers mussels Mytilus edulis and M. californianus; also barnacles Balanus, Pollicipes, Chthamalus; limpet Lottia, as well as herbivorous gastropods Tegula funebralis and Littorina. Feeding is by drilling with the radula, inserting the proboscis, and feeding on the soft body within. Species N. ostrina shows a wide food preference, but individuals seem to be consistent in diet (Abbott and Haderlie 1980). Predators: Cancer oregonensis. Adult snails prey on eggs. Behavior: Presence of N. ostrina elicits several escape responses from prey Mytilus edulis: gaping, spontaneous valve closure, foot activity, byssal fixing (Wayne 1980). Increase in air temperature reduces predation rate of Nucella ostrina on Balanus glandula while an increase in submerged body temperature results in an increase in predation rate (Yamane and Gilman 2009). Literature Cited 1. ABBOTT, D.P. and E. C. HADERLIE. 1980. Prosobranchia: marine snails, p.230-307. In: Intertidal invertebrates of California. R.H. MORRIS, D. P. ABBOTT, and E. C. HADERLIE (eds.). Stanford University Press, Stanford, California. 2. BERTNESS, M. D., and D. E. SCHNEIDER. 1976. Temperature relations of Puget Sound thaids in reference to their intertidal distribution. The Veliger. 19:47-78. 3. DAWSON, M. N., HAYS, C. G., GROSBERG, R. K., and RAIMONDI, P. T. 2014. Dispersal potential and population genetic structure in the marine intertidal of the Eastern North Pacific. Ecological Monographs. 84.3: 435-456. 4. HOLLIMAN, J. T., and C. HAND. 1962. A new species, genus, and family of marine flatworms (Turbellaria: Tricladia, Maricola) commensal with mollusks. The Veliger. 5:20-22. 5. HOUSTON, R. S. 1971. Reproductive biology of Thais emarginata (Deshayes 1839) and Thais canaliculata (Duclos 1832). The Veliger. 13:348-357 6. KEEN, A. M. and E.V. COAN. 1974. Marine molluscan genera of Western North America; an illustrated key. 2d ed. Stanford, Calif.: Stanford University Press. 7. KOZLOFF, E.N. 1974. Keys to the marine invertebrates of Puget Sound, the San Juan Archipelago, and adjacent regions. University of Washington Press, Seattle & London. 8. LEBOEUF, R. 1971. Thais emarginata (Deshayes): Description of the veliger and egg capsule. The Veliger. 14:205-211. 9. MARKO, P. B., PALMER, A. R., and VERMEIJ, G. J. 2003. Resurrection of Nucella ostrina (Gould, 1852), lectotype designation for N, emarginata (Deshayes, 1839), and molecular genetic evidence of Pleistocene speciation. The Veliger. 46:77-85. 10. MCLEAN, J.H. 2007. Shelled gastropoda, p. 713-753. In: The Light and Smith manual: intertidal invertebrates from central California to Oregon. J. T. Carlton (ed.). University of California Press, Berkeley. 11. MORAN, A. L. and EMLET, R. B. 2001. Offspring size and performance in variable environments: Field studies on a marine snail. Ecology. 82.6: 1597-1612. 12. OLDROYD, I. S. 1924. Marine shells of Puget Sound and vicinity. University of Washington Press, Seattle. 13. RICKETTS, E. F., and J. CALVIN. 1971. Between Pacific tides. Stanford University Press, Stanford, California. 14. WAYNE, T. 1980. Antipredator behavior of the mussel Mytilus edulis (Abstract). American Zoology. 20:789. 15. YAMANE, L. and GILMAN, S. E. 2009. Opposite responses by an intertidal predator to increasing aquatic and aerial temperatures. Marine Ecology Progress Series. 393: 27-36.