Metamynodon Layer (1892 AMNH Collection) (Oligocene of the United States)

Where: Shannon County, South Dakota (43.3° N, 102.5° W: paleocoordinates 44.4° N, 94.3° W)

• coordinate based on political unit

• small collection-level geographic resolution

When: lower Scenic Member (Brule Formation), Orellan (33.9 - 33.3 Ma)

Environment/lithology: terrestrial

Reposited in the AMNH

Primary reference: H. F. Osborn and J. L. Wortman. 1894. Fossil mammals of the Lower Miocene White River beds. Collection of 1892. Bulletin of the American Museum of Natural History 6(7):199-228 [J. Alroy/J. Alroy/M. Carrano]more details

PaleoDB collection 17141: authorized by John Alroy, entered by John Alroy on 18.10.1995, edited by Jonathan Marcot

Creative Commons license: CC BY (attribution)

Taxonomic list

• based on Sinclair 1924, Clark and Kietzke 1967, and Bjork and Macdonald 1981, "Metamynodon Channels" refers to any sandstone in the entire Scenic Member; however, this particular collection appears to represent a narrow interval in the basal Scenic of southwestern Badlands
list of Bjork and Macdonald 1981 spans the entire member and apparently is incomplete; following i.d.s cannot be matched to the AMNH list: Protapirus sp. Agriochoerus sp. "Perchoerus sp." - described by Lemley 1971
type of Heptacodon occidentale is from the "Metamynodon sandstones"; see Scott 1940
Mammalia
 Perissodactyla - Amynodontidae
Metamynodon planifrons Scott and Osborn 1887 odd-toed ungulate
erroneously listed as "M. planiceps" in a table; type of "M. rex" is from Pine Ridge Agency, see Troxell 1921c
 Perissodactyla - Hyracodontidae
Hyracodon sp. Leidy 1856 odd-toed ungulate
 Perissodactyla - Rhinocerotidae
Subhyracodon mitis1 Cope 1875 rhinoceros
 Perissodactyla - Tapiridae
Colodon occidentalis1 Leidy 1868 tapir
 Perissodactyla - Equidae
Equidae indet.2 Gray 1821 horse
Mesohippus exoletus4 Cope 1874 anchitheriine horse
one of the "M. bairdi" specimens later named as the type of "M. trigonostylus" by Osborn 1918; said to be from the "Metamynodon sandstones in the Middle Oreodon beds" by Scott 1941; not clear if M. bairdi sensu stricto is present
 Carnivora - Nimravidae
Hoplophoneus primaevus Leidy and Owen 1851 false sabre-tooth
 Ungulata - Merycoidodontidae
"Merycoidodon culbertsoni" = Merycoidodon (Merycoidodon) culbertsoni1
"Merycoidodon culbertsoni" = Merycoidodon (Merycoidodon) culbertsoni1 Leidy 1848 oreodont
 Ungulata - Tayassuidae
Perchoerus nanus3 Marsh 1894 peccary
AMNH 1200; "Metamynodon channels, Big Badlands, Cheyenne River, SD"
 Ungulata - Entelodontidae
Archaeotherium mortoni1 Leidy 1850 even-toed ungulate
 Ungulata - Anthracotheriidae
Aepinacodon americanus1 Leidy 1856 anthracothere
Heptacodon curtus1 Marsh 1894 anthracothere