Hemipsalodon
| Hemipsalodon | |
|---|---|
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| Skull of Hemipsalodon grandis | |
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| Restoration of H. grandis | |
Scientific classification 
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | †Hyaenodonta |
| Superfamily: | †Hyainailouroidea |
| Family: | †Hyainailouridae |
| Subfamily: | †Hyainailourinae |
| Genus: | †Hemipsalodon Cope, 1885 |
| Type species | |
| †Hemipsalodon grandis Cope, 1885
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| Species | |
| Synonyms | |
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synonyms of species:
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Hemipsalodon ("half-scissor tooth") is an extinct genus of hyainailourid hyaenodonts from the subfamily Hyainailourinae that lived in North America during the middle to late Eocene.[5][6] H. grandis was the largest hyaenodont found in North America, weighing 430–760 kilograms (950–1,680 lb).
Description
[edit]The skull of Hemipsalodon grandis is 45 centimetres (18 in) in length, with a lower jaw length of 34 centimetres (13 in). The most complete skull (O.M.S.I. No. 619), belonged to an old individual. It is powerfully-built, and overall superficially resembles the mesonychid Harpagolestes. The nasal opening is quite large. The canines are greatly enlarged. The anterior portion of the skull is broad anteriorly, but narrows down considerably posteriorly.[7] H. grandis was estimated to have weigjed 430–760 kilograms (950–1,680 lb), making it the largest hyaenodont to roam North America.[8]
Paleoecology
[edit]H. grandis was found in the Calf Creek locality of Cypress Hills Formation. It would've coexisted with fellow hyaenodont Hyaenodon. Carnivorans that were present in this formation were daphoeninae amphicyonids Brachyrhynchocyon dodgei and Daphoneus, nimravids Dinictis and Hoplophoneus, hesperocyonine canid Hesperocyon gregarius, and the subparictid Parictis.[9][10] Contemporary herbivores include the hyracodontid Hyracodon priscidens, rhinoceroses such as Subhyracodon occidentalis, Trigonias osborni, and Penetrigonias sagittatus, tapirid Colodon occidentalis, brontothere Megacerops kuwagatarhinus, the equid Mesohippus, and the anthracothere Bothriodon advena.[11] The predators present in Calf Creek likely practiced niche partitioning because of their different body sizes. Hemipsalodon, being the largest hypercarnivore present, focused on prey that weighed 780 kg (1,720 lb). The large size of Hemipsalodon would’ve allowed it to prey on large herbivores such as Megacerops kuwagatarhinus.[12]
References
[edit]- ^ "Hemipsalodon". Retrieved 21 September 2025.
- ^ E. D. Cope (1885.) "The White River beds of Swift Current River, Northwest Territory." American Naturalist 19(2):163
- ^ E. P. Gustafson (1986.) "Carnivorous mammals of the Late Eocene and Early Oligocene of Trans-Pecos Texas." Texas Memorial Museum Bulletin 33:1-66
- ^ Schlaikjer, Erich M. (1935). "Contributions to the stratigraphy and paleontology of the Goshen Hole area, Wyoming. III. A new basal Oligocene formation". Bulletin of the Museum of Comparative Zoology. 76 (3): 71–93.
- ^ McKenna, Malcolm C.; Bell, Susan K. (1997). Classification of Mammals Above the Species Level. New York: Columbia University Press. ISBN 978-0-231-11012-9. Retrieved 16 March 2015.
- ^ G. F. Gunnell (1998.) "Creodonta". In C. M. Janis, K. M. Scott, and L. L. Jacobs (eds.), "Evolution of Tertiary Mammals of North America, Volume 1: Terrestrial Carnivores, Ungulates, and Ungulate like Mammals", Cambridge University Press, 703 pages Hemipsalodon
- ^ Mellett, James Silvan (1969). "A skull of Hemipsalodon (Mammalia, Deltatheridia) from the Clarno Formation of Oregon". American Museum Novitates (2387). hdl:2246/2597.
- ^ Egi, Naoko (2001). "Body mass estimates in extinct mammals from limb bone dimensions: the case of North American hyaenodontids". Palaeontology. 44 (3): 497–528. Bibcode:2001Palgy..44..497E. doi:10.1111/1475-4983.00189. S2CID 128832577.
- ^ Bryant, Harold N. (1993). "Carnivora and Creodonta of the Calf Creek Local Fauna (Late Eocene, Chadronian), Cypress Hills Formation, Saskatchewan". Journal of Paleontology. 67 (6): 1032–1046. Bibcode:1993JPal...67.1032B. doi:10.1017/S0022336000025361. JSTOR 1306120.
- ^ Christison, Brigid E; Gaidies, Fred; Pineda-Munoz, Silvia; Evans, Alistair R; Gilbert, Marisa A; Fraser, Danielle (2022-01-25). Powell, Roger (ed.). "Dietary niches of creodonts and carnivorans of the late Eocene Cypress Hills Formation". Journal of Mammalogy. 103 (1): 2–17. doi:10.1093/jmammal/gyab123. ISSN 0022-2372. PMC 8789764. PMID 35087328. Retrieved 17 October 2024 – via Oxford Academic.
- ^ PBDB: Calf Creek
- ^ Christison, Brigid E; Gaidies, Fred; Pineda-Munoz, Silvia; Evans, Alistair R; Gilbert, Marisa A; Fraser, Danielle (2022-01-25). Powell, Roger (ed.). "Dietary niches of creodonts and carnivorans of the late Eocene Cypress Hills Formation". Journal of Mammalogy. 103 (1): 2–17. doi:10.1093/jmammal/gyab123. ISSN 0022-2372. PMC 8789764. PMID 35087328. Retrieved 17 October 2024 – via Oxford Academic.
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