Metamynodon Layer (1892 AMNH Collection): Orellan, South Dakota

List of taxa
Where & when
Taphonomy & methods
Metadata & references
Taxonomic list
Mammalia - Perissodactyla - Amynodontidae
Metamynodon planifrons Scott and Osborn 1887
erroneously listed as "M. planiceps" in a table; type of "M. rex" is from Pine Ridge Agency, see Troxell 1921c
Mammalia - Perissodactyla - Hyracodontidae
Hyracodon sp. Leidy 1856
Mammalia - Perissodactyla - Rhinocerotidae
Aceratherium mite Cope 1875
    = Subhyracodon mitis Cope 1875
Alroy 2002
Mammalia - Perissodactyla - Tapiridae
Colodon dakotensis Osborn and Wortman 1895
    = Colodon occidentalis Leidy 1868
Alroy 2002
and "C. procuspidatus" types of Osborn and Wortman 1895
Mammalia - Perissodactyla - Equidae
Mesohippus cf. obliquidens Osborn 1904
    = Equidae indet. Gray 1821
Lemley 1971
Mesohippus exoletus (Cope 1874)
Prothero and Shubin 1989
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
Mammalia - Carnivora - Nimravidae
Hoplophoneus primaevus (Leidy and Owen 1851)
Mammalia - Ungulata - Merycoidodontidae
Oreodon culbertsonii (Leidy 1848)
    = Merycoidodon culbertsoni Leidy 1848
Alroy 2002
recombined as Merycoidodon (Merycoidodon) culbertsoni
Mammalia - Ungulata - Tayassuidae
Perchoerus nanus (Marsh 1894)
Prothero 2009
AMNH 1200; "Metamynodon channels, Big Badlands, Cheyenne River, SD"
Mammalia - Ungulata - Entelodontidae
Elotherium mortoni (Leidy 1850)
    = Archaeotherium mortoni Leidy 1850
Alroy 2002
as well as "E. imperator"; presumably includes "? Entelodon cf. magnus" from Lower Brule "Metamynodon sandstones" of Scott 1940
Mammalia - Ungulata - Anthracotheriidae
Hyopotamus americanus n. sp. Leidy 1856
    = Aepinacodon americanus Leidy 1856
Alroy 2002
of "A." rostratus is also from the "Metamynodon sandstones (lower Oreodon beds)": Troxell 1921a
Anthracotherium curtum (Marsh 1894)
    = Heptacodon curtus Marsh 1894
Alroy 2002
discussed in text but omitted from table
see common names

Country:United States State/province:South Dakota County:Shannon
Coordinates: 43.3° North, 102.5° West (view map)
Paleocoordinates:44.4° North, 94.3° West
Basis of coordinate:based on political unit
Geographic resolution:small collection
Period:Paleogene Epoch:Oligocene
Stage:Rupelian 10 m.y. bin:Cenozoic 4
Key time interval:Orellan
Age range of interval:33.90000 - 33.30000 m.y. ago
* legacy (obsolete) database fields
Formation:Brule Member:lower Scenic
Local section:BgBad Local bed:4
Local order:bottom to top
Lithology and environment
Environment:terrestrial indet.
Modes of preservation:body
Collection methods and comments
Museum repositories:AMNH
Taxonomic list comments: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
Database number:17141
Authorizer:J. Alroy, J. Marcot Enterer:J. Alroy, J. Marcot
Research group:vertebrate
Created:1995-10-18 00:00:00 Last modified:2002-06-03 03:27:41
Access level:the public Released:1995-10-18 00:00:00
Creative Commons license:CC BY
Reference information

Primary reference:

2711. 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]

Secondary references:

6294 J. Alroy. 2002. Synonymies and reidentifications of North American fossil mammals. [J. Alroy/J. Alroy/M. Uhen]
2221 R. E. Lemley. 1971. Proceedings of the South Dakota Academy of Sciences 50 [J. Alroy/J. Alroy]
57282 D. R. Prothero. 2009. The Early Evolution of the North American Peccaries (Artiodactyla: Tayassuidae). Papers on Geology, Vertebrate Paleontology, and Biostratigraphy in Honor of Michael O. Woodburne (Museum of Northern Arizona Bulletin 65) 509-541 [J. Marcot/J. Marcot]
6273 D. R. Prothero and N. Shubin. 1989. The evolution of Oligocene horses. In D. R. Prothero and R. M. Schoch (eds.), The Evolution of Perissodactyls 142-175 [J. Alroy/J. Alroy/J. Marcot]