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// Workers AI · dad joke modeWhat did the Perchoerus say? "Pig"ging out.

From Wikipedia, the free encyclopedia

Perchoerus
Temporal range: Late Eocene - Early Oligocene
36–30 Ma
Left maxilla fragments of P. minor (specimen USNM 206190)
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Placentalia
Order: Artiodactyla
Family: Tayassuidae
Genus: Perchoerus
Leidy, 1869
Type species
Palaeochoerus probus
Leidy, 1856
Species
  • P. minor Cook, 1922
  • P. nanus Marsh, 1894
  • P. probus (Leidy, 1856)
Synonyms[1]
  • Bothrolabis Cope, 1888
  • Chaenohyus Cope, 1879

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

[edit]

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

[edit]
  • 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

[edit]

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

[edit]
  1. 1 2 3 4 5 6 7 8 Prothero, Donald R. (2009). "THE EARLY EVOLUTION OF THE NORTH AMERICAN PECCARIES" (PDF). Museum of Northern Arizona Bulletin. 65: 509–542. Archived from the original (PDF) on 20 November 2023.
  2. 1 2 3 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. JSTOR 1005504.
  3. 1 2 3 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.
  4. 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. hdl:11336/54840. ISSN 1064-7554.
  5. 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. p. 365.
  6. 1 2 3 Prothero, Donald R.; Williams, Mary Persis (2016). The Princeton Field Guide to Prehistoric Mammals. Princeton University Press. pp. 157–158. ISBN 9781400884452.
  7. 1 2 3 Boardman, Grant S.; Secord, Ross (1 April 2013). "Stable isotope paleoecology of White River ungulates during the Eocene–Oligocene climate transition in northwestern Nebraska". Palaeogeography, Palaeoclimatology, Palaeoecology. 375: 38–49. Bibcode:2013PPP...375...38B. doi:10.1016/j.palaeo.2013.02.010. Retrieved 17 November 2024 via Elsevier Science Direct.