Twin Buttes (Upper Bridger) (Eocene of the United States)

Where: Sweetwater County, Wyoming (41.7° N, 109.0° W: paleocoordinates 45.6° N, 95.1° W)

• coordinate based on political unit

When: upper Member (Bridger Formation), Bridgerian (50.3 - 46.2 Ma)

Environment/lithology: terrestrial

Primary reference: C. L. Gazin. 1976. Mammalian Faunal Zones of the Bridger Middle Eocene. Smithsonian Contributions to Paleobiology 26:1-25 [J. Alroy/J. Alroy/J. Marcot]more details

PaleoDB collection 16449: authorized by John Alroy, entered by John Alroy on 26.03.1995, edited by Mark Uhen

Creative Commons license: CC BY (attribution)

Taxonomic list

• available records are from Bridger D, but Bridger C is definitely exposed and some records may pertain to it
133 MPM specimens from Twin Buttes White Layer: West 1979
Show authors, comments, and common names
Mammalia
 Theriamorpha - Herpetotheriidae
Peratherium comstocki3
Peratherium comstocki3 Cope 1884 marsupial
"late Bridgerian"
 Condylarthra - Hyopsodontidae
Hyopsodus paulus5
Hyopsodus paulus5 Leidy 1870 condylarth
"NE Twin Buttes (low D)"
 Artiodactyla - Helohyidae
Helohyus lentus6, Helohyus milleri6
Helohyus lentus6 Marsh 1871 even-toed ungulate
Bridger D
Helohyus milleri6 Sinclair 1914 even-toed ungulate
 Theriamorpha - Nyctitheriidae
"Scenopagus curtidens" = Nyctitherium curtidens2
"Scenopagus curtidens" = Nyctitherium curtidens2 Matthew 1909 placental
 Rodentia - Sciuravidae
Sciuravidae indet.1, Pauromys schaubi n. sp.
Sciuravidae indet.1 Miller and Gidley 1918 rodent
Pauromys schaubi n. sp. Wood 1959 rodent
see Wood 1959
 Primates - Microsyopidae
Uintasorex parvulus4
Uintasorex parvulus4 Matthew 1909 primate
YPM specimen, but species is restricted to the upper Bridger according to Gazin
1Dawson 1962; 2Krishtalka 1976; 3Krishtalka and Stucky 1983; 4Szalay 1969; 5West 1979; 6West 1984