Monroe Creek Formation Explained

Monroe Creek Formation
Type:	Geological formation
Age:	Paleogene
Period:	Paleogene

The Monroe Creek Formation is a geologic formation in South Dakota. It preserves fossils dating back to the Paleogene period.

Fossil content

Mammals

Carnivorans

Carnivorans reported from the Monroe Creek Formation
Genus	Species	Presence	Material	Notes	Images
Enhydrocyon	E. crassidens	Shannon County, South Dakota.^[1]	Crushed skull (AMNH 12886) & other skull elements.	A hesperocyonine dog.
	E. pahinsintewakpa		Multiple specimens.	A hesperocyonine dog.
Leptocyon	L. delicatus	Porcupine Creek, South Dakota.^[2]	Left partial ramus (ACM 31102).	A canine dog, may instead be from the Harrison Formation.
Mammacyon	M. obtusidens	Wounded Knee Area.	Skull & partial skeleton (ACM 34-41).	A bear-dog.
Neocynodesmus	N. delicatus	Porcupine Creek, Wounded Knee Area.	Left mandible (ACM 31102).	Junior synonym of Leptocyon.
Nimravus	N. sectator	Wounded Knee Area.	Left ramus (AMNH 12882).	Possibly instead from the Harrison Formation.
Nothocyon	N. geismarianus	Wounded Knee Area.^[3]	Fragmentary ramus (AMNH 12872).	An arctoid formerly thought to be a canid.
	N. near latidens	Wounded Knee Area.	Jaw fragment (AMNH 12873).	Reassigned to Phlaocyon.
Promartes	P. gemmarosae	Wounded Knee Area.	Nearly-complete skeleton (ACM 31-33).	A mustelid.

Rodents

Rodents reported from the Monroe Creek Formation
Genus	Species	Presence	Material	Notes	Images
Allomys	A. harkseni	Wounded Knee Area.	Molars.	An aplodontid.
Capatanka	C. brachyceps	Wounded Knee Area.	Skull (AMNH 12902).	A castorid, possibly instead from the Harrison Formation.
Meniscomys	M. sp. indeterminate	Wounded Knee Area.	Isolated tooth (SDSM 59157).	An aplodontid.
Palaeocastor	P. simplicidens	Wounded Knee Area.	Partial cranium (AMNH 12900).	A castorid.
Pleurolicus	P. dakotensis	Wounded Knee Area.	Left ramus (AMNH 12893).	A gopher.
Promylagaulus	P. cf. riggsi	Wounded Knee Area.	Isolated molar.	A mylagaulid.

Ungulates

Ungulates reported from the Monroe Creek Formation
Genus	Species	Presence	Material	Notes	Images
Nanotragulus	N. ordinatus	Wounded Knee Area.	Mandibles.	May instead be from the Harrison Formation.
Parahippus	P. pristinus	Wounded Knee Area.	Hind feet (AMNH 12922).	May instead be from the Harrison Formation.

Reptiles

Squamates

See also

• List of fossiliferous stratigraphic units in South Dakota
• Paleontology in South Dakota

References

• Web site: Fossilworks: Gateway to the Paleobiology Database. ((Various Contributors to the Paleobiology Database)). 17 December 2021.

Notes and References

1. Wang . Xiaoming . 1994 . Phylogenetic systematics of the Hesperocyoninae (Carnivora, Canidae). . Bulletin of the AMNH . en-US . 221 . 6–207. 2246/829 .
2. Book: Tedford . Richard H. . Phylogenetic systematics of the North American fossil Caninae (Carnivora, Canidae). (Bulletin of the American Museum of Natural History, no. 325) . Wang . Xiaoming . Taylor . Beryl E. . 2009 . [New York] : American Museum of Natural History. . 2246/5999 . en-US.
3. Macdonald . J. R. (James Reid) . Thomson . Albert Report of the expedition of 1906 to the Miocene on Pine Ridge Indian Reservation . 1963 . The Miocene faunas from the Wounded Knee area of western South Dakota. Bulletin of the AMNH; v. 125, article 3 . 2246/1259 . en-US.
4. Scarpetta . Simon G. . October 2019 . Peltosaurus granulosus (Squamata, Anguidae) from the Middle Oligocene of Sharps Corner, South Dakota, and the Youngest Known Chronostratigraphic Occurrence of Glyptosaurinae . Journal of Vertebrate Paleontology . 39 . 3 . e1622129 . 10.1080/02724634.2019.1622129 . 2019JVPal..39E2129S . 0272-4634.