First mesonychid from the Clarno Formation (Eocene) of Oregon, USA

dc.contributor.authorRobson, Selina V.
dc.contributor.authorFamoso, Nicholas
dc.contributor.authorDavis, Edward Byrd
dc.contributor.authorHopkins, Samantha S.B.
dc.date.accessioned2024-10-02T22:28:53Z
dc.date.available2024-10-02T22:28:53Z
dc.date.issued2019-06
dc.description13 pages
dc.description.abstractA recently identified left dentary of Harpagolestes cf. uintensis represents the first mesonychid material known from the Pacific Northwest. The specimen is from the Hancock Quarry (Clarno Unit, John Day Fossil Beds National Monument), which is in the uppermost subunit of the Clarno Formation (middle Eocene, ~40 Ma). The sediments of the Hancock Quarry were deposited by a meandering river system during the middle Eocene when north-central Oregon had a subtropical climate. As with many other mammals from the Hancock Quarry, Harpagolestes participated in an Asian-North American faunal interchange; species of Harpagolestes are known from the Eocene of both continents. Harpagolestes was carnivorous, and members of the genus were likely bone-crushers. Characteristic bone-crushing wear is visible on the occlusal surfaces of the Hancock Quarry specimen’s premolars and molars. With the aid of CT scans, it has been determined that the Hancock Quarry Harpagolestes contains the alveoli for c1, p1-2, and m3, and preserves the crowns of p3-4 and m1-2. The molariform teeth have a large, conical trigonid with a bulbous talonid. The protoconid of p3 and p4 is tilted posteriorly. This specimen of Harpagolestes cf. uintensis represents a new large carnivore in the Hancock Quarry ecosystem, adds to the known diversity of the Oregon middle Eocene, and is the only known occurrence of a mesonychid in the Pacific Northwest.
dc.identifier.doihttps://doi.org/10.26879/856
dc.identifier.urihttps://hdl.handle.net/1794/30093
dc.language.isoen_US
dc.publisherPalaeontologia Electronica
dc.rightsCreative Commons BY-NC-SA
dc.subjectMesonychia
dc.subjectClarno Formation
dc.subjectPacific Northwest
dc.subjectEocene
dc.subjectMammalia
dc.titleFirst mesonychid from the Clarno Formation (Eocene) of Oregon, USA
dc.typeArticle

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