Hsanda Gol Formation

Hsanda Gol Formation Stratigraphic range: Oligocene
Type	Geological formation
Location
Region	Asia
Country	Mongolia

The Hsanda Gol Formation is a geological formation dating from the Oligocene, located in Central Mongolia in the Tsagan Nor basin. The fossilised animals are mostly Middle Oligocene mammals, with an abundance of rodents.^[1][2]

Geology

The 2600 feet thick Hsanda Gol formation is covered in various places by Miocene-age variegated clays, sands, and gravels. It rests on top of the Early Cretaceous Hühteeg Svita formation. The lower portions of the formation are composed of yellow conglomerate, with the higher areas being dominated by red clays, silts and sands, as well as lava and basalt flows.

During the Oligocene, the area is believed to have been a sparse plain with few wooded areas, due to the absence of large herbivores (with the exception of Paraceratherium, which is known from the formation).^[3]

Paleobiota

Amphibians

Amphibians of the Hsanda Gol Formation
Genus	Species	Location	Stratigraphic Position	Abundance	Notes	Images
Macropelobates	M. osborni				A frog.

Reptiles

Reptiles of the Hsanda Gol Formation
Genus	Species	Location	Stratigraphic Position	Abundance	Notes	Images
Crythiosaurus	C. mongoliensis				An amphibaenian.

Mammals

Rodents

Rodents of the Hsanda Gol Formation
Genus	Species	Location	Stratigraphic Position	Abundance	Notes	Images
Cricetops	C. dormitor dormitor C. dormitor elephantus				A Cricetid.
Cyclomylus	C. lohensis				A Cylindrodontid.
Eumys	E. asiaticus				A Cricetid.
Karakoromys	K. decessus Indeterminate				A gundi.
Plesispermophilus	P. lohiculus
Prosciurus	Indeterminate
Pseudocylindrodon	Indeterminate				A Cylindrodontid.
Selenomys	S. mimucs				Possibly a mountain beaver.
Tataromys	T. sigmodon T. plicidens T. deflexus				A gundi.
Tsaganomys	T. altaicus				A Cylindrodontid.

Lagomorphs

Lagomorphs of the Hsanda Gol Formation
Genus	Species	Location	Stratigraphic Position	Abundance	Notes	Images
Desmatolagus	D. gobiensis D. robustus
Ochotonolagus	O. argyropuloi
Sinolagomys	S. tatalgolicus

Carnivorans

Carnivorans of the Hsanda Gol Formation
Genus	Species	Location	Stratigraphic Position	Abundance	Notes	Images
Amphicticeps	A. shackelfordi				A Miacidae.	Nimravus jaw.
Amphicynodon	A. teilhardi				A small bear.
Cynodictis	C. elegans C. constans				A small bear dog.
Nimravus	Indeterminate				A Nimravid.
Palaeogale	P. ulyesses P. parvula				A mustelid.
Palaeoprionodon	P. gracilis				A feliform.
Plesictis	Indeterminate				A mustelid.
Proailurus	Indeterminate				An early felid.

Perissodactyls

Perissodactyls of the Hsanda Gol Formation
Genus	Species	Location	Stratigraphic Position	Abundance	Notes	Images
Paraceratherium	P. grangeri				A giant hornless rhinoceros of the family Hyracodontidae.	Paraceratherium.

Artiodactyls

Artiodactyls of the Hsanda Gol Formation
Genus	Species	Location	Stratigraphic Position	Abundance	Notes	Images
Eumeryx	E. culminis				A cervid
Miometyx	Indeterminate				A cervid.
Palaeohypsodontus	P. asiaticus				A bovine.
Pseudomeryx	P. gobiensis				A member of Gelocidae.

Creodonts

Creodonts of the Hsanda Gol Formation
Genus	Species	Location	Stratigraphic Position	Abundance	Notes	Images
Hyaenodon	H.pervagus H. aymardi H. ambiguus H. compressus				A large predatory Creodont.	Hyaenodon.

References

1. Fossil Mammals from the Oligocene Hsanda Gol Formation, Mongolia: With Notes on the Paleobiology of Cricetops Dormitor. Insectivora, rodentia and deltatheridia, Part 1, James Silvan Mellett, 1966
2. The Oligocene Hsanda Gol Formation, Mongolia : a revised faunal list
3. The Oligocene Hsanda Gol Formation, Mongolia : a revised faunal list