Article · Wikipedia archive · Last revised May 27, 2026

Notostylops

Notostylops is a genus of extinct South American notoungulates from Eocene Argentina. Fossils of the genus have been found in the Sarmiento, Casamayor, Andesitas Huancache and Koluel Kaike Formations.

Last revised
May 27, 2026
Read time
≈ 2 min
Length
378 w
Citations
6
Source
Wikipedia ↗
Notostylops
Notostylops
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Placentalia
Order: †Notoungulata
Family: †Notostylopidae
Genus: †Notostylops
Ameghino, 1897
Species
Synonyms

Notostylops ("south pillar face") is a genus of extinct South American notoungulates from Eocene Argentina. Fossils of the genus have been found in the Sarmiento, Casamayor, Andesitas Huancache and Koluel Kaike Formations.1

  • Size comparison of Notostylops murinus with a human.
    Size comparison of Notostylops murinus with a human.
  • Life reconstruction.
    Life reconstruction.

Description

Notostylops was a very generalised animal, very similar to the first eutherians and ungulates. It would have superficially resembled a marmot or a wombat and is suspected to have browsed on low-growing plants. It was probably adapted to a fairly wide range of ecological niches, but its robustness indicates it had some digging adaptations.23 Its tall skull housed rodent-like incisor teeth. Notostylops incisors lacked complex, decussating enamel prisms, instead possessing radial enamel.4 The endocast of N. murinus had a volume of 9,807 mm3, with the volume of the olfactory bulbs being 629 mm3. Notostylops had a degree of cranial flexure of 34˚.5 Notostylops was about 75 centimetres (30 in) long.6

References

References

  1. Notostylops at Fossilworks.org
  2. Croft, Darin. Horned Armadillos and Rafting Monkeys. Indiana University Press.
  3. Lorente, Malena; Gelfo, Javier; Lopez, Guillermo (2018). "First skeleton of the notoungulate mammal Notostylops murinus and palaeobiology of Eocene Notostylopidae". Lethaia. 52 (2): 244–259. doi:10.1111/let.12310. S2CID 135127572.
  4. Filippo, Andréa; Kalthoff, Daniela C.; Billet, Guillaume; Gomes Rodrigues, Helder (13 March 2019). "Evolutionary and Functional Implications of Incisor Enamel Microstructure Diversity in Notoungulata (Placentalia, Mammalia)". Journal of Mammalian Evolution. 27 (2): 211–236. doi:10.1007/s10914-019-09462-z. ISSN 1064-7554. Retrieved 31 October 2025 – via Springer Nature Link.
  5. Perini, Fernando A.; Macrini, Thomas E.; Flynn, John J.; Bamba, Kanvaly; Ni, Xijun; Croft, Darin A.; Wyss, André R. (23 November 2021). "Comparative Endocranial Anatomy, Encephalization, and Phylogeny of Notoungulata (Placentalia, Mammalia)". Journal of Mammalian Evolution. 29 (2): 369–394. doi:10.1007/s10914-021-09583-4. ISSN 1064-7554. Retrieved 17 January 2026 – via Springer Nature Link.
  6. Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 250. ISBN 978-1-84028-152-1.