Irdin Manha Formation Explained

Irdin Manha Formation
Period:	Eocene
Age:	Eocene
Type:	Geological formation
Region:	Inner Mongolia

The Irdin Manha Formation is a geological formation from the Eocene located in Inner Mongolia, China, a few kilometres south of the Mongolian border.^[1]

Fossil content

Mammals

U.S. paleontologists Henry Fairfield Osborn and Roy C. Andrews discovered two premolars on the site in 1923, and assigned the specimen to the new genus Eudinoceras because he believed it to be related to "Dinoceras" (now known as Uintatherium). Within a decade, however, as more complete specimens were recovered, the animal was identified as a Mongolian relative to the North American pantodont Coryphodon. The expedition also lead to the discovery of the only known skull of Andrewsarchus.^[2]

Artiodactyls

Artiodactyls reported from the Irdin Manha Formation
Genus	Species	Presence	Material	Notes	Images
Achaenodontidae?			An incomplete upper tooth (AMNH 20136).^[3]	Doubtfully assigned to the family.
Cf. Archaeomeryx, gen indet.			Fragment of lower jaw (AMNH 20173).	A traguliform.
Andrewsarchus	A. mongoliensis	Around Telegraph Line Camp.^[4]	A large skull.^[5]	A relative of entelodonts formerly thought to be a mesonychid.
Erlianhyus	E. primitivus	Irdin Manha, Erlian Basin, Nei Mongol.^[6]	A right upper maxilla with P3–M3 (IVPP V 28275).	A basal artiodactyl.
Gobiohyus	G. orientalis	Telegraph Line Camp.^[7]	Jaw elements.	A helohyid also found in the Ulan Shireh Formation.
	G. pressidens	Telegraph Line Camp.	Partial right rami.	A helohyid.
	G. robustus	Telegraph Line Camp.	Left ramus (AMNH 20246).	A helohyid.
Obotherium	O. parvum	Irdin Manha, Erlian Basin, Nei Mongol.^[8]	Teeth and lower jaws	A tapirulid.

Ferae

Ferae reported from the Irdin Manha Formation
Genus	Species	Presence	Material	Notes	Images
Miacis	M. invictus		Isolated upper molar (AMNH 20137).	A miacid.
Propterodon	P. irdinensis		Jaw fragments.	A hyaenodontid.
Sarkastodon	S. mongoliensis	About 25 miles southwest of Iren Dabasu.^[10]	Skull & jaws.	An oxyaenid.

Glires

Glires reported from the Irdin Manha Formation
Genus	Species	Presence	Material	Notes	Images
Advenimus	A. burkei	Near Camp Margetts.^[11]	Jaw elements.	A ctenodactyloid rodent.
Asiomys	A. dawsoni	Huheboerhe.^[12]	Fragment of right calcaneus (IVPP V24417).	An ischyromyid rodent.
Erenlagus	E. anielae	Huheboerhe.^[13]	Teeth.	A stem-lagomorph.
Gomphos	G. shevyrevae	Huheboerhe escarpment.^[14]	Teeth & foot elements.	A mimotonid.
Ischyromyidae genus indet.	Species A	Irdin Manha escarpment.	Right calcaneus (IVPP V24416).	Relatively large ischyromyid rodent, calcaneus comparable in size to that of a coypu or Asiatic brush-tailed porcupine.
	Species B	Daoteyin Obo.	Right calcaneus (IVPP V24418).	Large ischyromyid rodent with calcaneus matching in length that of a coypu & similar in structure to that of Paramys.
Mimolagus	M. aurorae	Irdin Manha escarpment.^[15]	Teeth & foot elements.	A large mimotonid.
Pappocricetodon	P. neimongolensis	Huheboerhe.^[16]	Teeth.	A cricetid rodent.
	P. cf. P. zhongtiaensis	Huheboerhe.	A left molar.	A cricetid rodent.
	P. sp.	Huheboerhe.	A right molar.	A cricetid rodent.
Paramyidae	Paramyid spp.		Teeth & jaws.	3 sizes of paramyid rodents, possibly different species.
	?Paramyid sp.		Left jaw (AMNH 80801).	Possible small paramyid rodent.
Simplicimys	S. bellus	Huheboerhe.^[17]	Teeth.	A ctenodactyloid rodent also known from the Arshanto Formation.
Strenulagus	S. solaris	Irdin Manha and Huheboerhe localities.^[18]	Isolated cheek teeth, fragmentary upper incisors (dI2) and postcranial elements.	A stem-lagomorph also known from the Khaychin Formation.
Tamquammys	T. fractus	Huheboerhe.	Right maxilla (V17798).	A ctenodactyloid rodent.
	T. wilsoni		Teeth.	A ctenodactyloid rodent also known from the Arshanto & Nomogen formations.
Yongshengomys	Y. extensus	Huheboerhe.	Teeth.	A ctenodactyloid rodent.
Yuomys	Y. huheboerhensis	Huheboerhe.	Teeth.	A ctenodactyloid rodent.
	Y. sp. A	Huheboerhe.	A right molar (V17805).	A ctenodactyloid rodent.
	Y. sp. B	Huheboerhe.	A right molar (V17806).	A ctenodactyloid rodent.
	Y. sp. C	Huheboerhe.	A right molar (V17807).	A ctenodactyloid rodent.

Mesonychians

Mesonychians reported from the Irdin Manha Formation
Genus	Species	Presence	Material	Notes	Images
Hapalodectes	?H. auctus		An upper molar or possibly premolar (AMNH 20130).	A hapalodectid.
	H. serus	Around Telegraph Line Camp.	Lower cheek tooth (AMNH 20172).	A hapalodectid.
Harpagolestes	H. leei	Huheboerhe & Daoteyin Obo.^[19]	Tooth elements.	A mesonychid.
Mesonychidae	Gen. indet.		AMNH 20132.	About the size of Harpagolestes uintensis.
	Gen. indet.		Isolated tooth (AMNH 20133).	About the size of Synoplotherium lanius.
Mongolonyx	M. dolichognathus	7 miles west of Camp Margetts.	Jaw elements.	A large mesonychid.

Perissodactyls

Perissodactyls reported from the Irdin Manha Formation
Genus	Species	Presence	Material	Notes	Images
Caenolophus	C. proficiens		Lower jaw & isolated teeth.^[20]	A rhinocerotoid.
Cooperia	C. totadentata	Telegraph Line Camp, 23 miles southeast of Iren Dabasu.^[21]	Front of skull (AMNH 20116).	Generic name preoccupied, renamed Forstercooperia.
Desmatotherium	D. fissum		Upper jaw fragment.	A helaletid.
	D. mongoliense	Irdin Manha escarpment, Duheminboerhe, Huheboerhe & Chaganboerhe.^[22]	Parts of 10 individuals.^[23]	A helaletid also found in the Mergen Formation.
Forstercooperia	F. totadentata	Telegraph Line Camp, 23 miles southeast of Iren Dabasu.	Front of skull (AMNH 20116).	A paraceratheriid, originally named Cooperia.
	F. ulanshirehensis	Irdin Manha site.^[24]	Jaw elements.	A paraceratheriid also known from the Ulan Shireh Formation.
Gnathotitan	G. berkeyi	Irdin Manha.^[25]	Jaw elements.	A brontothere.
Lophialetes	L. expeditus		Jaw elements.	A lophialetid.
	L. minutus		Upper molar.	A lophialetid.
Metatelmatherium	M. cristatum	Camp Margetts.	Skull & lower jaw (AMNH 26411).	A brontothere.
	M. parvum	Irdin Manha.	Fragment of left lower jaw (AMNH 20168).	A brontothere.
Microtitan	M. mongoliensis		Jaw elements.	A brontothere.
Pappaceras	P. confluens	Upper gray clays & Camp Margetts area.^[26]	Skull & jaw elements.	A paraceratheriid.
Paracolodon	P. fissus	Duheminboerhe & Daoteyin Obo.	Skull elements & teeth.	A helaletid.
Protitan	P. bellus	Spring Camp, East Mesa, Shara Murun region.	Palatal side of skull (AMNH 26104).	A brontothere.
	P. grangeri		Skull elements.	A brontothere.
	P. minor	Camp Margetts.	Skull elements.	A brontothere.
	P. obliquidens	Irdin Manha.	Part of left maxilla (AMNH 20125).	A brontothere.
	P. robustus	Irdin Manha.	Jaw elements & teeth.	A brontothere.
Protitanotherium	P. mongoliense		Lower jaw & foot bones (AMNH 18653).	Moved to the genus Rhinotitan.
Rhinotitan	R. mongoliensis		Lower jaw & foot bones (AMNH 18653).	A brontothere originally reported as a species of Protitanotherium.
Rostriamynodon	R. grangeri	East of Camp Margetts.^[27]	Complete skull & mandible (AMNH 107635).	An amynodontid.
Teleolophus	T. medius		Teeth & jaws.

Primates

Reptiles

Birds

Birds reported from the Irdin Manha Formation
Genus	Species	Presence	Material	Notes	Images
Buteoninae		Chimney Butte.^[29]	Left coracoid (AMNH FR 2941).	Specimen reassigned to Eogrus? sp.
Eogrus	E. aeola	Chimney Butte.	Right metatarsus (AMNH 2936).	An eogruid.
	E.? sp.	Chimney Butte.	Left coracoid (AMNH FR 2941).	Formerly thought to represent a buteonine, now thought to be an eogruid.^[30]
Telecrex	T. grangeri	Chimney Butte, Shara Murun region.^[31]	An incomplete right femur (AMNH 2942).	A guineafowl, formerly thought to be a rail.

Testudines

Testudines reported from the Irdin Manha Formation
Genus	Species	Presence	Material	Notes	Images
"Adocus"	"A". orientalis	Telegraph Line Camp.^[33] ^[34]	Anterior half of plastron (AMNH 6356).	An adocid.
Amyda?	A.? johnsoni	Telegraph Line Camp.	Two-thirds of a carapace (AMNH 6357) & many carapace fragments (AMNH 6359).	A softshell turtle.
Trionychidae	Indeterminate	Telegraph Line Camp.	Several kinds of sculptured fragments (AMNH 6360).	Remains of softshell turtles.

Fish

Fish reported from the Irdin Manha Formation
Genus	Species	Presence	Material	Notes	Images
Pappichthys	P. mongoliensis	Telegraph Line Camp.^[35]	Vertebrae.^[36]	Specimens now believed to represent Siluriformes.
Siluriformes	Indeterminate	Telegraph Line Camp, Chahar Province.	5 vertebrae (AMNH 8535).	A catfish likely related to ictalurids. Formerly assigned to Pappichthys mongoliensis.

See also

• List of fossil sites

Notes and References

1. . Retrieved July 2013.
2. Osborn . Henry Fairfield . Granger . Walter . August 17, 1932 . Coryphodonts and uintatheres from the Mongolian Expedition of 1930. . American Museum Novitates . en-US . 552 . 1–16. 2246/3000 .
3. Matthew . William Diller . Granger . Walter . November 21, 1925 . New mammals from the Irdin Manha Eocene of Mongolia. . American Museum Novitates . en-US . 198 . 1–10. 2246/3182 .
4. Szalay . Frederick S. . Gould . Stephen Jay . 1966 . Asiatic Mesonychidae (Mammalia, Condylarthra). . Bulletin of the AMNH . en-US . 132 . 2. 2246/1112 .
5. Osborn. H. F.. Andrewsarchus, giant mesonychid of Mongolia. American Museum Novitates. American Museum of Natural History. 11 November 1924. 146. live. https://web.archive.org/web/20201102065222/http://digitallibrary.amnh.org/bitstream/handle/2246/3226/N0146.pdf;jsessionid=49D5559007A639D9D5FC35E0030DF06F?sequence=1. 2 November 2020.
6. Li . Qian . Li . Qi . 2022-10-03 . A new middle Eocene bunodont artiodactyl from the Erlian Basin (Nei Mongol, China) . Historical Biology . en . 34 . 10 . 1941–1949 . 10.1080/08912963.2021.1989679 . 239828310 . 0891-2963.
7. Coombs . Margery C. . Coombs . Walter P. . 1977 . Dentition of Gobiohyus and a Reevaluation of the Helohyidae (Artiodactyla) . Journal of Mammalogy . 58 . 3 . 291–308 . 10.2307/1379328 . 1379328 . 0022-2372.
8. Bai . Bin . Wang . Yuan-Qing . Theodor . Jessica M. . Meng . Jin . 2023 . Small artiodactyls with tapir-like teeth from the middle Eocene of the Erlian Basin, Inner Mongolia, China . Frontiers in Earth Science . 11 . 10.3389/feart.2023.1117911 . 2296-6463 . free .
9. Osborn . Henry Fairfield . Granger . Walter . Andrews . Roy Chapman . Matthew . William Diller . 1931 . Coryphodonts of Mongolia: Eudinoceras mongoliensis Osborn, E. kholobolchiensis sp. nov. . American Museum Novitates . en-US . 459. 2246/3066 .
10. Granger . Walter . Garber . A. Z. . April 21, 1938 . A giant oxyaenid from the Upper Eocene of Mongolia. . American Museum Novitates . en-US . 969 . 1–5. 2246/2199?show=full .
11. Dawson . Mary . 1964 . Late Eocene rodents (Mammalia) from Inner Mongolia . American Museum Novitates . 2191 . 2246/3304 . en-US.
12. Fostowicz-Frelik . Łucja . López-Torres . Sergi . Li . Qian . 2021-06-02 . Tarsal morphology of ischyromyid rodents from the middle Eocene of China gives an insight into the group's diversity in Central Asia . Scientific Reports . en . 11 . 1 . 11543 . 10.1038/s41598-021-90796-1 . 34078948 . 8172891 . 2021NatSR..1111543F . 2045-2322.
13. Fostowicz-Frelik . Łcja . Li . Qian . 2014-12-31 . A new genus of stem lagomorph (Mammalia: Glires) from the Middle Eocene of the Erlian Basin, Nei Mongol, China . Acta Zoologica Cracoviensia . en . 57 . 1 . 29–42 . 10.3409/azc.57_1-2.29 . 0065-1710.
14. Meng . Jin . Kraatz . Brian P. . Wang . Yuanqing . Ni . Xijun . Gebo . Daniel L . Beard . K. Christopher . 2009-11-30 . A New Species of Gomphos (Glires, Mammalia) from the Eocene of the Erlian Basin, Nei Mongol, China . American Museum Novitates . en . 3670 . 1–11 . 10.1206/673.1 . 0003-0082.
15. Fostowicz-Frelik . Łucja . Li . Chuankui . Mao . Fangyuan . Meng . Jin . Wang . Yuanqing . 2015-03-30 . A large mimotonid from the Middle Eocene of China sheds light on the evolution of lagomorphs and their kin . Scientific Reports . en . 5 . 1 . 9394 . 10.1038/srep09394 . 25818513 . 4377629 . 2045-2322.
16. Li . Qian . July 2012 . Middle Eocene Cricetids (Rodentia, Mammalia) from The Erlian Basin, Nei Mongol, China . Vertebrata PalAsiatica . 50 . 3 . 237–244.
17. Book: Li . Qian . New ctenodactyloid rodents from the Erlian Basin, Nei Mongol, China, and the phylogenetic relationships of Eocene Asian ctenodactyloids . Meng . Jin . 2015 . American Museum of Natural History . New York, NY.
18. Łucja . Fostowicz-Freldc . Chuankui . Li . Qian . Li . Jin . Meng . Yuanqing . Wang . March 3, 2015 . Strenulagus (Mammalia: Lagomorpha) from the Middle Eocene Irdin Manha Formation of the Erlian Basin, Nei Mongol, China . Acta Geologica Sinica - English Edition . en . 89 . 1 . 12–26 . 10.1111/1755-6724.12391. 128886984 .
19. Jin . Xun . July 2012 . New mesonychid (Mammalia) material from the lower Paleogene of the Erlian Basin, Nei Mongol, China . Vertebrata PalAsiatica . 50 . 3 . 245–257.
20. Matthew . William Diller . Granger . Walter . November 23, 1925 . The smaller perissodactyls of the Irdin Manha Formation, Eocene of Mongolia. . American Museum Novitates . en-US . 199 . 1–9. 2246/3183 .
21. Wood . Horace Elmer . December 30, 1938 . Cooperia totadentata, a remarkable rhinoceros from the Eocene of Mongolia. . American Museum Novitates . en-US . 1012 . 1–20. 2246/2209?show=full .
22. Book: Bai, Bin . New material of Eocene Helaletidae (Perissodactyla, Tapiroidea) from the Irdin Manha Formation of the Erlian Basin, Inner Mongolia, China, and comments on related localities of the Huheboerhe area . 2017 . New York, NY : American Museum of Natural History . American Museum of Natural History Library.
23. Osborn . Henry Fairfield . October 17, 1923 . Titanotheres and lophiodonts in Mongolia. . American Museum Novitates . en-US . 91 . 1–5. 2246/3206 .
24. Book: Wang . Hai-bing . A new species of Forstercooperia (Perissodactyla, Paraceratheriidae) from northern China with a systematic revision of forstercooperiines . Wang . Hai-bing . Bai . Bin . Meng . Jin . Wang . Yuanqing . 2018 . American Museum of Natural History . New York, NY.
25. Granger . Walter . Gregory . William K. . February 4, 1943 . A revision of the Mongolian titanotheres. . Bulletin of the AMNH . en-US . 80 . 10 . 349–389. 2246/383 .
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27. Wall . William P. . Manning . Earl . 1986 . Rostriamynodon grangeri n. gen., n. sp. of Amynodontid (Perissodactyla, Rhinocerotoidea) with Comments on the Phylogenetic History of Eocene Amynodontidae . Journal of Paleontology . 60 . 4 . 911–919 . 10.1017/S0022336000043079 . 1305081 . 59363111 . 0022-3360.
28. Ni . Xijun . Meng . Jin . Beard . K. Christopher . Gebo . Daniel L. . Wang . Yuanqing . Li . Chuankui . 2010-01-22 . A new tarkadectine primate from the Eocene of Inner Mongolia, China: phylogenetic and biogeographic implications . Proceedings of the Royal Society B: Biological Sciences . en . 277 . 1679 . 247–256 . 10.1098/rspb.2009.0173 . 0962-8452 . 2842661 . 19386655.
29. Wetmore . Alexander . 1934 . Fossil birds from Mongolia and China. . American Museum Novitates . en-US . 711 . 1–16. 2246/2095 .
30. Web site: Division of Paleontology . 2023-02-05 . research.amnh.org.
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32. Mook . Charles Craig . 1940 . A new fossil crocodilian from Mongolia. . American Museum Novitates . en-US . 1097 . 1–3. 2246/2242 .
33. Danilov . I. G. . Sukhanov . V. B. . Syromyatnikova . E. V. . 2011 . New Asiatic materials on turtles of the family Adocidae with a review of the Adocid record in Asia . Proceedings of the Zoological Institute RAS . 315 . 2 . 101–132 . 10.31610/trudyzin/2011.315.2.101. 55392207 . free .
34. Gilmore . Charles W. . 1931 . Fossil turtles of Mongolia. . Bulletin of the AMNH . en-US . 59 . 4. 2246/345 .
35. Stucky . Richard K. . 1982 . Early Fossil Catfish from Mongolia . Copeia . 1982 . 2 . 465–467 . 10.2307/1444634 . 1444634 . 0045-8511.
36. Hussakof . Louis . Granger . Walter . 1932 . The fossil fishes collected by the Central Asiatic Expeditions . American Museum Novitates . 553 . 2246/3001 . en-US.