CRICETIDAE FISCHER VON WALDHEIM, 1817

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 : 22

CRICETIDAE FISCHER VON WALDHEIM, 1817

Referred specimen —Incisor, JODA 4957.

Occurrence —UCMP V4834.

Description —The incisor is a long oval shape (deeper than wide) in cross section with a curved face, bearing no ornamentation. The incisor has a length of 11.92 mm.

Remarks — Copemys Wood, 1936 (known from the Barstovian Sucker Creek, Quartz Basin and Skull Springs localities) has an incisor size and shape consistent with this specimen and similarly lacks ornamentation ( Lindsay 2008). The eomyids Pseudadjidaumo Shotwell, 1956 (known from the Barstovian Quartz Basin locality) and Leptodontomys Shotwell, 1956 (known from Arikareean, Clarendonian, and Hemphillian localities in Oregon) are far smaller than Copemys and JODA 4957 ( Shotwell 1956, Korth and Samuels 2015). In addition, Pseudadjidaumo has rounded enamel and smooth incisors (Flynn 2008). The eomyid Pseudotheridomys Schlosser, 1926 (known from the Barstovian Skull Springs and Quartz Basin localities) is similar in size to Copemys , but it bears a transversely compressed incisor ( Shotwell 1967). This specimen marks the only identifiable occurrence of cricetids in the Mascall Formation, collected from the Mascall Tuff. The lack of cricetid material, however, is most likely due to preservational issues.