Parablastomeryx, FRICK, 1937

Maguire, Kaitlin Clare & Schmitz, Joshua X. Samuels and Mark D., 2022, The fauna and chronostratigraphy of the middle Miocene Mascall type area, John Day Basin, Oregon, USA, PaleoBios 35, pp. 1-51 : 37

PARABLASTOMERYX FRICK, 1937

Parablastomeryx sp. FRICK, 1937

FIG. 22

Referred specimens —From JDNM-4*: Left m1, JODA 2255; From JDNM-71A: Left M1 or M2, JODA 17389; p4, JODA 17437.

Occurrence —JDNM-4*, JDNM-71A.

Description —JODA 2255 is a brachydont lower molar with the Palaeomeryx fold, anteroposterior length of 10.27 mm and transverse width of 5.81 mm. JODA 17389 is also brachydont with a broken protocone, anteroposterior length of 8.62 mm and transverse width of 8.14 mm.

Remarks —This is the largest genus of blastomerycine (Prothero 2008). JODA 2255 falls within the size range of Parablastomeryx from Virgin Valley (UCMP 10661, 11564–11567) and presence of the Palaeomeryx fold and brachydont molars places it within this taxon (Prothero 2008). Two species ( P. gregorii Frick, 1937 and P. flori- danus White, 1940) are recognized in the genus during the Miocene; however, the material is not sufficient for species level identification (Prothero 2008). Hunt and Stepleton (2004) note two species of Parablastomeryx from Upper John Day Formation strata: Parablastomeryx cf. advena Matthew, 1907 from the late Arikareean age Johnson Canyon Member, and Parablastomeryx schultzi Frick, 1937 from the Hemingfordian age Rose Creek Member.The new records from the Mascall fauna indicate this genus persisted in Oregon from the late Arikareean (earliest Miocene) to early Barstovian (middle Miocene).

Figures

Figure 22. Parablastomeryx sp. A. Left m1 in occlusal view, JODA 2255. B. Left M1 or M2, JODA 17389. C. p4, JODA 17437. Scale bar=1mm.