Leptocyon sp.

Smith, Kent, Czaplewski, Nicholas & Cifelli, Richard L., 2016, Middle Miocene carnivorans from the Monarch Mill Formation, Nevada, Acta Palaeontologica Polonica 61 (1), pp. 231-252 : 236

Leptocyon sp.

Fig. 3B .

Material ( Fig. 3B ).—UCMP 141482, partial right m1 from UCMP V70138 (OMNH V967), Eastgate, Churchill County, Nevada, USA; Monarch Mill Formation, Barstovian (Miocene).

Measurements (in mm).—m1: AP, indeterminate (broken); T, 4.66.

Description.—UCMP 141482 is missing the paraconid and anterior root. The occlusal surface is slightly worn. The protoconid is much higher and more prominent than the metaconid. There is a deep notch between the protoconid and metaconid. A protostylid is present on the posterolabial base of the protoconid. The entoconid is much smaller than the hypoconid. The hypoconid is situated laterally on the talonid. The cristid obliqua is weak and does not reach the metaconid; thus, the talonid basin is open labially. The surface of the trenchlike talonid basin is rugose. The labial cingulum is moderately developed. A small hypoconulid is present.

Comparisons.—This small, isolated partial m1 is identified as Leptocyon sp. based on its size and presence of an open talonid and a reduced entoconid. These characters are among those listed by Munthe (1998) for this genus. Tedford et al. (2009) recognized the several species of the genus Leptocyon as paraphyletic; of the morphological characters these authors used to diagnose the genus, few can be observed in UCMP 141482. Unfortunately, no additional comment or further identification is possible.

Figures

Fig. 3. Canidae of the Eastgate LF, basal-most unit of the Monarch Mill Formation, Barstovian (Miocene), Churchill County, Nevada, USA. A. Tomarctus brevirostris, Cope, 1873, UCMP 141908, left dentary with p2, p4, partial m1, and m2 in lingual (A1), labial (A2), and occlusal (A3, stereopair) views. B. Leptocyon sp., UCMP 141482, right m1 in occlusal (B1), lingual (B2), and labial (B3) views.