PBDB Collection

Ahearn: Chadronian, South Dakota

List of taxa

Where & when

Geology

Taphonomy & methods

Metadata & references

Taxonomic list

Amphibia - Temnospondyli - Pelobatidae

	Eopelobates grandis Zweifel 1956
Reptilia

	Peltosaurus sp. Cope 1873

	Alligator cf. prenasalis (Loomis 1904)
Reptilia - Testudines - Trionychidae

	Amyda sp. Geoffroy Saint-Hilaire 1809
	"scrap"
	= Apalone leucopotamica Cope 1891	Hutchison 1996
	original and current combination Trionyx leucopotamicus
Reptilia - Testudines

	Dermatemydidae indet. Baur 1888
	"Pseudanosteira or Anosteira... scrap"
	= Anosteirinae indet. Lydekker 1889	Hutchison 1996
Reptilia - Testudines - Emydidae

	Graptemys sp. Agassiz 1857
	"scrap"
	= Emydidae indet. Rafinesque 1815	Lutugin 1894

	Trachemys sp. Agassiz 1857
	"scrap"
	= Emydidae indet. Rafinesque 1815	Lutugin 1894
Mammalia - Rodentia - Eomyidae

	Eomyidae indet. Winge 1887
Mammalia - Rodentia - Ischyromyidae

	Ischyromys sp. Leidy 1856
Mammalia - Carnivora - Amphicyonidae

	Daphoenocyon minor n. sp. Clark et al. 1967
	synonym of Brachyrhynchocyon dodgei
Mammalia - Carnivora - Ursidae

	Parictis gilpini n. sp. Clark and Guensburg 1972	Clark and Guensburg 1972
	Little Corral Draw, Pennington Co.

	Parictis parvus n. sp. Clark and Beerbower 1967
	from west flank of Quinn Draw, Shannon Co.: see Clark and Guensburg 1972
Mammalia - Carnivora - Subparictidae

	Parictis dakotensis Clark 1936	Clark and Guensburg 1972
	recombined as Subparictis dakotensis
	SE 1/4 NE 14 NW 1/4 sec 5 T4S R12E, Pennington Co.; same as type locality of P. gilpini
Mammalia - Carnivora - Nimravidae

	? Eusmilus sp. Gervais 1876
Mammalia - Creodonta - Hyaenodontidae

	Hyaenodon cf. montanus Douglass 1902

	Hyaenodon cf. horridus Leidy 1853
Mammalia - Merycoidodontidae

	Merycoidodon sp. Leidy 1848
	"Big Corral Draw... Pennington Co.:" discussed by Stevens and Stevens 1996

	Miniochoerus cf. forsythae (Schultz and Falkenbach 1968)	Stevens and Stevens 1996
	one specimen of "Merycoidodon sp."; said to to "probably" be this species
Mammalia - Agriochoeridae

	Agriochoerus cf. antiquus Leidy 1850
Mammalia - Hypertragulidae

	Hypertragulidae indet. Cope 1879
Mammalia - Protoceratidae

	Poabromylus kayi Peterson 1932
	(1 measurement)
	= Pseudoprotoceras longinaris Cook 1934	Emry and Storer 1981
	replaces ID of Wilson 1974; FMNH collection
Mammalia - Tylopoda

	Tylopoda indet. Illiger 1811
	"camelid new genus and species": may be Montanatylopus; specimens not discussed by Prothero 1986
Mammalia - Tayassuidae

	Perchoerus cf. minor Cook 1922
	= Tayassuidae indet. Palmer 1897	Wright 1998
	= Perchoerus minor Cook 1922	Prothero 2009
	FMNH PM22407
Mammalia - Entelodontidae

	Archaeotherium cf. scotti Sinclair 1922
	= Archaeotherium cf. altidens Sinclair 1922	Alroy 2002
	original and current combination Scaptohyus altidens

	Archaeotherium cf. mortoni Leidy 1850

	Archaeotherium cf. coarctatum (Cope 1889)
Mammalia - Anthracotheriidae

	Bothriodon sp. Aymard 1846
	= Anthracotheriidae indet. Leidy 1869	Kron and Manning 1998
	this is indeterminate and could be Aepinacodon
Mammalia - Camelidae

	Poebrotherium cf. andersoni Troxell 1917
	= Poebrotherium sp. Leidy 1847	Alroy 2002
	species not recognized by Honey et al. 1998, who list P. eximium in the Chadron Fm. of South Dakota; slab includes Mesohippus, hypertragulid, Parictis parvus, and new camelid
Mammalia - Perissodactyla - Equidae

	Mesohippus celer (Marsh 1874)

	Mesohippus hypostylus Osborn 1904
	synonym of Mesohippus bairdi

	Mesohippus viejensis Clark and Beerbower 1967
	synonym of Mesohippus bairdi
	(1 measurement)
Mammalia - Perissodactyla - Tapiridae

	Colodon occidentalis (Leidy 1868)
Mammalia - Perissodactyla - Rhinocerotidae

	Trigonias sp. Lucas 1900

	Caenopus mitis (Cope 1875)
	= Subhyracodon mitis Cope 1875	Alroy 2002
Mammalia - Perissodactyla - Hyracodontidae

	Hyracodon cf. priscidens Lambe 1905
	probably OK in light of Prothero 1996e
Mammalia - Perissodactyla - Brontotheriidae

	Menodus sp. (Pomel 1848)
	= Brontotheriidae indet. Marsh 1873	Alroy 2002
	could include any of three genera; see Mader 1989
see common names

Geography

Country:	United States	State/province:	South Dakota	County:	Pennington and Shannon
Coordinates:	43.6° North, 102.5° West (view map)
Paleocoordinates:	44.9° North, 93.6° West
Basis of coordinate:	based on political unit

Time

Period:	Paleogene	Epoch:	Eocene
Stage:	Priabonian	10 m.y. bin:	Cenozoic 3
*Period:	Tertiary
Key time interval:	Chadronian
Age range of interval:	37.00000 - 33.90000 m.y. ago
* legacy (obsolete) database fields

Stratigraphy

Formation:	Chadron	Member:	Ahearn
Local section:	BgBad	Local bed:	1
Local order:	bottom to top

Lithology and environment

Primary lithology:	not reported
Environment:	terrestrial indet.

Taphonomy

Modes of preservation:	body
Size of fossils:	macrofossils

Collection methods and comments

Reason for describing collection:	paleoecologic analysis
Taxonomic list comments:dated at 36.3 +/- 0.7, 35.1, and 36.2 Ma: Emry et al. 1987; average is 35.87 (= 36.80) Ma

Metadata

Database number:	16885
Authorizer:	J. Alroy, J. Marcot	Enterer:	J. Alroy, J. Marcot
Modifier:	M. Uhen	Research group:	vertebrate
Created:	1993-02-18 00:00:00	Last modified:	2022-03-07 08:22:32
Access level:	the public	Released:	1993-02-18 00:00:00
Creative Commons license:	CC BY

Reference information

Primary reference:

1235.

ETE 10023

J. Clark and J. R. Beerbower. 1967. Geology, paleoecology, and paleoclimatology of the Chadron Formation. Fieldiana 5(5):21-74 [J. Alroy/J. Alroy/J. Alroy]

Secondary references:

1238		J. Clark and T. E. Guensburg. 1972. Arctoid genetic characters as related to the genus Parictis. Fieldiana 26(1):1-71 [J. Alroy/J. Alroy/J. Marcot]
1454		R. J. Emry and J. E. Storer. 1981. The Hornless Protoceratid Pseudoprotoceras (Tylopoda: Artiodactyla) in the Early Oligocene of Saskatchewan and Wyoming. Journal of Vertebrate Paleontology 1(1):101-110 [J. Alroy/J. Alroy/M. Uhen]
34290		J. H. Hutchison. 1996. Testudines. In D. R. Prothero and R. J. Emry (eds.), The Terrestrial Eocene-Oligocene Transition in North America 337-353 [J. Alroy/J. Alroy]
6312		D. G. Kron and E. Manning. 1998. Anthracotheriidae. In C. M. Janis, K. M. Scott, and L. L. Jacobs (eds.), Evolution of Tertiary mammals of North America 381-388 [J. Alroy/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]
86699		M. S. Stevens, D. R. Prothero, C. Cleaveland, E. Welsh, K. Marriott, T. Htun, D. Balassa, S. M. Olson, K. I. Watmore and D. Wheeler. 2023. Systematics of the Late Oligocene and Miocene Oreodonts (Merycoidodontidae: Artiodactyla). New Mexico Museum of Natural History and Science Bulletin 93:1-226 [J. Marcot/J. Marcot]
6270		M. S. Stevens and J. B. Stevens. 1996. Merycoidodontinae and Miniochoerinae. In D. R. Prothero and R. J. Emry (eds.), The Terrestrial Eocene-Oligocene Transition in North America 498-573 [J. Alroy/J. Alroy/J. Alroy]
6238		D. B. Wright. 1998. Tayassuidae. In C. M. Janis, K. M. Scott, and L. L. Jacobs (eds.), Evolution of Tertiary mammals of North America 389-401 [J. Alroy/J. Alroy/J. Alroy]