Biology:Perchoerus
| Perchoerus | |
|---|---|
| |
| Left maxilla fragments of P. minor (specimen USNM 206190) | |
Scientific classification 
| |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Family: | Tayassuidae |
| Genus: | †Perchoerus Leidy, 1869 |
| Type species | |
| Palaeochoerus probus Leidy, 1856
| |
| Species | |
| |
| Synonyms[1] | |
| |
Perchoerus is an extinct genus of suine (pig-like mammal) from the Eocene and Oligocene of North America. Three species are known.[2][1][3] While often considered one of the earliest peccaries (Tayassuidae), other studies have recovered it to be a basal suine outside of either peccaries or Suidae (Old World pigs).[4] Perchoerus is a rare component of the White River fauna, and the largest species, P. probus, also occurs in the John Day Formation of Oregon.[1]
Description
Perchoerus had a steeply-sloped skull with a short snout. It was similar in some respects to Thinohyus, another peccary-like suine from the Oligocene of the John Day Formation. Both are rare, and historically Perchoerus and Thinohyus have often been confused for each other.[2] There are still some clear differences: Perchoerus has a shorter snout, stronger sagittal crests, and more lightly-built zygomatic and occipital areas. In addition, its M3 (upper third molar) is simpler and shorter from front-to-back, and there is less of a gap (diastema) between its canines and premolars.[3][1]
As reported by Scott (1913), the molars of Perchoerus are generally quadrituberculate (four-cusped) and lack any of the accessory cuspules (minor cusps) present in modern peccaries. The feet bore 4 functional digits and had free metacarpals. The bones in the forearm were separate rather than fused.[5]
Species
- P. minor is the oldest and smallest known species of Perchoerus, only the size of a house cat.[6] It is known from skull and tooth material from the Chadronian (latest Eocene, 36-34 Ma) of Nebraska, South Dakota, and Wyoming.[1] Apart from its minuscule size, the jaw more slender and the molars more simple than other Perchoerus species.[1]
- P. nanus was slightly younger and larger, from the Orellan (earliest Oligocene, 34-32 Ma) of Nebraska, South Dakota, and Colorado. It was intermediate between the other two species in anatomy.[1][6]
- P. probus was the latest and largest species, from the Whitneyan to early Arikareean (Oligocene, 32-30 Ma) of Nebraska, South Dakota, and Oregon. The type species of Perchoerus, P. probus was about as large as living peccaries (~35 kg (77 lb)),[7] and is known from more remains than the other species. Apart from its larger size, it also had larger cheek teeth and a more complex structure of its third molars (m3 and M3).[1][3][6]
Palaeoecology
Low δ13C values from the teeth of P. probus suggest that it was an inhabitant of dense riparian habitats.[7] The rarity of its fossils also support a preference for forests (where fossil preservation is difficult),[2] and its tooth structure implies that it was a browser of tough vegetation.[7]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Prothero, Donald R. (2009). "THE EARLY EVOLUTION OF THE NORTH AMERICAN PECCARIES". Museum of Northern Arizona Bulletin 65: 509–542. http://www.donaldprothero.com/files/92367802.pdf.
- ↑ 2.0 2.1 2.2 Scott, William Berryman; Jepsen, Glenn Lowell (1940). "The Mammalian Fauna of the White River Oligocene: Part IV. Artiodactyla". Transactions of the American Philosophical Society 28 (4): 363–746. doi:10.2307/1005504. ISSN 0065-9746. https://www.jstor.org/stable/1005504.
- ↑ 3.0 3.1 3.2 Prothero, Donald R. (2021). "The systematics of North American peccaries (Mammalia: Artiodactyla: Tayassuidae)". New Mexico Museum of Natural History and Science Bulletin 85: 6-8. https://books.google.com/books?id=fJcwEAAAQBAJ&printsec=frontcover#v=onepage&q&f=false.
- ↑ Parisi Dutra, Rodrigo; Casali, Daniel de Melo; Missagia, Rafaela Velloso; Gasparini, Germán Mariano; Perini, Fernando Araujo; Cozzuol, Mario Alberto (2016-09-13). "Phylogenetic Systematics of Peccaries (Tayassuidae: Artiodactyla) and a Classification of South American Tayassuids". Journal of Mammalian Evolution 24 (3): 345–358. doi:10.1007/s10914-016-9347-8. ISSN 1064-7554. http://dx.doi.org/10.1007/s10914-016-9347-8.
- ↑ Scott, William Berryman (1913). A history of land mammals in the Western Hemisphere; illustrated with 32 plates and more than 100 drawings. New York: Macmillan. pp. 365. https://www.biodiversitylibrary.org/item/51389.
- ↑ 6.0 6.1 6.2 Prothero, Donald R.; Williams, Mary Persis (2016). The Princeton Field Guide to Prehistoric Mammals. Princeton University Press. pp. 157–158. ISBN 9781400884452.
- ↑ 7.0 7.1 7.2 Boardman, Grant S.; Secord, Ross (1 April 2013). "Stable isotope paleoecology of White River ungulates during the Eocene–Oligocene climate transition in northwestern Nebraska" (in en). Palaeogeography, Palaeoclimatology, Palaeoecology 375: 38–49. doi:10.1016/j.palaeo.2013.02.010. Bibcode: 2013PPP...375...38B. https://www.sciencedirect.com/science/article/pii/S0031018213000862. Retrieved 17 November 2024.
Template:Suina Wikidata ☰ Q21235313 entry
 |  |
