Trogosus

Trogosus Temporal range: Early Eocene–Middle Eocene PreꞒ Ꞓ O S D C P T J K Pg N
Trogosus hyracoides skull at the National Museum of Natural History
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	† Tillodontia
Family:	† Esthonychidae
Subfamily:	† Trogosinae
Genus:	† Trogosus Leidy 1871
Species [1]
†T. castoridens (type) †T. gazini †T. grangeri †T. hillsii †T. hyracoides †T. latidens

Trogosus is an extinct genus of tillodont mammal. Fossils have been found in Wyoming, ^[2] California, ^[3] and British Columbia, ^[4] and date from the Eocene between 54.8 and 33.7 million years ago.

Description

Life restoration

Trogosus was a bear-like herbivore with a large, short skull and flat feet, and had a skull 35 cm (14 in) long with an estimated body weight of 150 kg (330 lb). ^[5] It had large, rodent-like incisors, which continued growing throughout the creature's life. Judging from the heavily worn molar teeth, Trogosus fed on rough plant material, such as roots and tubers. ^[6] Trogosus possessed an exposed midbrain, a small neocortex, an orbitotemporal canal ventral to rhinal fissure, large olfactory bulbs, and a broad circular fissure. Its tiny neocortex relative to contemporary carnivorans and artiodactyls may have disadvantaged it when escaping predation by the former and competing for resources with the latter. ^[2]

Notes

1. Trogosus in the Paleobiology Database. Retrieved July 2013.
2. Bertrand, Ornella C.; Jiménez Lao, Marina; Shelley, Sarah L.; Wible, John R.; Williamson, Thomas E.; Meng, Jin; Brusatte, Stephen L. (18 September 2023). "The virtual brain endocast of Trogosus (Mammalia, Tillodontia) and its relevance in understanding the extinction of archaic placental mammals". Journal of Anatomy . 244 (1): 1–21. doi:10.1111/joa.13951. ISSN   0021-8782. PMC  10734658. PMID   37720992.
3. Miyata, Kazunori; Deméré, Thomas A. (17 February 2016). "New material of a 'short-faced' Trogosus (Mammalia, Tillodontia) from the Delmar Formation (Bridgerian), San Diego County, California, U.S.A." . Journal of Vertebrate Paleontology. 36 (3): e1089878. Bibcode:2016JVPal..36E9878M. doi:10.1080/02724634.2016.1089878. S2CID   130776132 . Retrieved 11 April 2022.
4. Russell 1935
5. Kemp 2005 , p. 240
6. Palmer 1999 , p. 236

References

• Kemp, Tom S. (2005). The Origin and Evolution of Mammals. Oxford University Press. ISBN   0198507615. OCLC   56652579.
• Leidy, J. (1871). "Remains of extinct mammals from Wyoming". Proceedings of the Academy of Natural Sciences. 23: 113–116. Retrieved July 24, 2013.
• Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. ISBN   1-84028-152-9.
• Russell, Loris Shano (1935). "A middle Eocene mammal from British Columbia". American Journal of Science. 5. 29 (169): 54–55. Bibcode:1935AmJS...29...54R. doi:10.2475/ajs.s5-29.169.54.

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