Stockoceros

Stockoceros Temporal range: 1.8–0.012  Ma [1] PreꞒ Ꞓ O S D C P T J K Pg N ↓
S. conklingi skeleton
Life restoration
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Artiodactyla
Family:	Antilocapridae
Tribe:	† Stockoceratini
Genus:	† Stockoceros Skinner, 1942
Species
S. conklingi Stock, 1930 S. onusrosagris Roosevelt and Burden, 1934

Stockoceros is an extinct genus of the North American artiodactyl family Antilocapridae (pronghorns), ^[2] one known to have inhabited what is now Mexico and the Southwestern United States during the Pleistocene epoch. ^[1] The genus survived until about 12,000 years ago, and was present when Paleo-Indians arrived in North America from Eurasia. ^{[3] [4]}

Discovery

One of the co-discoverers and co-describers of S. onusrosagris, which has since been synonymised with the other species S. conklingi, ^[5] was Quentin Roosevelt II, grandson of United States President Theodore Roosevelt; he was 14 at the time of the discovery. ^{[6] [7]}

Description

The horns are each divided near their base into two prongs of roughly equal length. The horns were characterised by outward flaring. ^[5] Its molars possessed sharp apical cusps, although their extreme tips did exhibit a degree of rounding. ^[2]

Taxonomy

Though long considered separate species, a 2013 study found S. conklingi to be synonymous with S. onusrosagris, with the latter being the junior synonym and thus invalid. ^[5]

Palaeoecology

A dental mesowear and microwear study suggests that S. conklingi was a mixed feeder that would have engaged in both grazing and browsing behaviour. This pattern of feeding has been suggested to be reflective of seasonal selective feeding on grasses. S. conklingi had a significantly greater intake of grass into its diet as compared to the living pronghorn. ^[2]

S. conklingi skull

References

1. "Stockoceros Skinner 1942". Paleobiology Database . Retrieved 17 December 2021.
2. Rivals, Florent; Semprebon, Gina M. (12 June 2006). "A comparison of the dietary habits of a large sample of the Pleistocene pronghorn Stockoceros onusrosagris from the Papago Springs Cave in Arizona to the modern Antilocapra americana" . Journal of Vertebrate Paleontology . 26 (2): 495–500. doi:10.1671/0272-4634(2006)26[495:ACOTDH]2.0.CO;2. ISSN   0272-4634. S2CID   86134472 . Retrieved 24 September 2025– via ResearchGate.
3. "Stockoceros conklingi Stock 1930". Paleobiology Database . Retrieved 17 December 2021.
4. "Stockoceros onusrosagris Roosevelt and Burden 1934". Paleobiology Database . Retrieved 17 December 2021.
5. Bravo-Cuevas, Victor M.; Jiménez-Hidalgo, Eduardo; Cabral-Perdomo, Miguel A.; Priego-Vargas, Jaime (22 October 2013). "Taxonomy and notes on the paleobiology of the late Pleistocene (Rancholabrean) antilocaprids (Mammalia, Artiodactyla, Antilocapridae) from the state of Hidalgo, central Mexico". Revista mexicana de ciencias geológicas. 30 (3): 601–613. ISSN   1026-8774 . Retrieved 24 September 2025.
6. Roosevelt, Q.; Burden, J. W. (1934). "A new species of antilocaprine, Tetrameryx onusrosagris, from a Pleistocene cave deposit in southern Arizona". American Museum Novitates (754). AMNH: 1–4. hdl:2246/2114 . Retrieved 21 November 2015.
7. "Burden's Pronghorn: an Arizona Story". Prehistoric Pronghorn. International Wildlife Museum. Archived from the original on 22 November 2015. Retrieved 21 November 2015.

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