MUSTELIDAE 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 : 15-16

MUSTELIDAE FISCHER VON WALDHEIM, 1817 LEPTARCTUS LEIDY, 1857

Leptarctus oregonensis STOCK, 1930

Holotype —From CIT 113: Left partial maxilla with P4 and M1, right partial maxilla with P4, right M1, incisor, nasals, zygomatic arches, occipital crest, CIT 206.

is not narrow. It is too small to be Sthenictis Peterson, 1910 , another Barstovian mustelid. UCMP 39958 is unlike Watay tabutsigwii McLaughlin, Hopkins and Schmitz, 2016 from Hawk Rim, as that taxon has a trenchant talonid like hypercarnivorous ischyrictines. The talonid of UCMP 39958 is basined as in Martes Frisch, 1775 . It was originally identified as Martes ( Downs 1951) ; however, Anderson (1994) and Hughes (2012) have questioned whether many “ Martes ” taxa prior to the late Miocene were related to the extant genus. Sato et al. (2003) suggested the oldest true Martes is M. wenzensis Frisch, 1775 from the Pliocene of Poland ( Wolsan 1989). Anderson (1994) suggested the extant Martes americana Turton, 1806 is a late Pleistocene immigrant to North America. The locality for UCMP 39958 is unknown ( V 67153 is assigned to specimens with no locality information for the Mascall Formation). The specimen tag in the UCMP says Mascall or Rattlesnake Formation. Downs (1951) mentions UCMP 39958 and states “it cannot be considered a valid Mascall allocation” (pg. 102). Given the material, more precise taxonomic identification is not possible and it remains unknown if this specimen belongs to the Mascall or Rattlesnake Formation. The oldest known and well-dated member of the subfamily including Martes , the Guloninae , is Pekania occulta Samuels and Cavin, 2013 from the Rattlesnake Formation.