SORICIDAE FISCHER VON WALDHEIM, 1817 HETEROSORICINAE VIRET AND ZAPFE, 1951

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 : 12

SORICIDAE FISCHER VON WALDHEIM, 1817 HETEROSORICINAE VIRET AND ZAPFE, 1951 PSEUDOTRIMYLUS GUREEV, 1971

Pseudotrimylus mawbyi REPENNING, 1967

FIG. 4

Referred specimen —Left dentary fragment with m1 through m3, JODA 13865.

Description —Referral to this taxon was based on the following diagnostic characters: m1 is low-crowned and all cingulum are inflated; entoconid is a blunt cuspid detached from metaconid and thoroughly merged with the hypolophid; metalophid joins protolophid labially; talonid of the m3 has cresentic loph, is not distinctly bicuspid and is very small compared to the m1; the stout molars are far to the rear relative to the anterior edge of the ascending ramus; mental foramen is below the talonid of the m1 and placed in a depression on the labial side of the dentary that leads to the premolar region anterodorsally ( Repenning 1967).

Remarks — Repenning (1967) described the new species Trimylus mawbyi from UOMNCH 19486, found five miles southwest of the south end of Guano Lake in Lake County, Oregon. He placed it within the Barstovian and noted that the associated fauna is “virtually identical to that from the Mascall Formation”. UOMNCH 19486 was originally described and assigned to Heterosorex Gaillard, 1915 by Mawby (1960), who also noted the specimen was from a Mascall Formation equivalent. Additional referred specimens for the species are from the Beatty Buttes fauna, age equivalent to the Mascall Formation ( Repenning 1967, Gunnell et al. 2008). The species was reassigned to Pseudotrimylus by Gunnell et al. (2008).

Figures

Figure 4. Pseudotrimylus mawbyi left dentary with m1– m3 in occlusal view, JODA 13865. Scale bar=1mm.