Hemiacodon engardae, Murphey and Dunn, 2009

Murphey, Paul C. & Kelly, Thomas S., 2017, Mammals from the earliest Uintan (middle Eocene) Turtle Bluff Member, Bridger Formation, southwestern Wyoming, USA, Part 2: Apatotheria, Lipotyphla, Carnivoramorpha, Condylartha, Dinocerata, Perissodactyla and Artiodactyla, Palaeontologia Electronica (Cambridge, England: 2003) 20 (2), pp. 1-51 : 40-41

Hemiacodon engardae 30

Microparamys sp. 32 Leptoreodon pusillus 19

new cylindrodont or ailuravine sp. 32

cf. Pareumys sp. 32

sciuravid sp. A 32 Metanoiamys sp. 32

Elymys ? emryi 32

Wickia sp. , cf. W. brevirhinus 33

Triplopus sp. , cf. T. obliquidens 33

Epihippus sp. , cf. E. gracilis 33

Merycobunodon? walshi 33

ascending order); the Blacks Fork Member, the Twin Buttes Member, and the Turtle Bluff Member (TBM). The Blacks Fork and Twin Buttes members contain mammalian faunas of the Blackforkian (biochron Br2) and Twinbuttean (biochron Br3) subages of the Bridgerian North American Land Mammal age. The TBM has been designated as the stratotype for the earliest Uintan biochron Ui1a of the Uintan North American Land Mammal age ( Gunnell et al., 2009). As such, documenting the taxonomic composition of the TBM further clarifies our understanding of the Bridgerian-Uintan transition.

Gunnell et al. (2009) listed two index species for the Ui1a; Hemiacodon engardae and Oromerycidae , new genus and species (= Merycobunodon? walshi new species, this paper). Kelly and Murphey (2016a) described a new dipodoid, Elymys ? emryi, from the TBM, which is also a Ui1a index species restricted to the TBM. With the discovery of Nyctitherium gunnelli and Entomolestes westgatei , a total of five Ui1a index species can for now be confidently recognized from the TBM ( Table 5). Six other taxa ( Sespedectinae , genus undetermined, unnamed lipotyphlan sp., cf. Pareumys sp. , sciruavid sp. A, Metanoiamys sp. , and Microparamys sp. )

TABLE 5 (continued).