Brachyprotoma Explained

Brachyprotoma, also known as the short-faced skunks, is an extinct genus of large skunk that inhabited Pleistocene North America, with specimens having been found from Yukon to West Virgina.^{[1] [2] [3]} There currently exists only one accepted species, Brachyprotoma obtusata.^[4]

Description

Brachyprotoma obtusata is known solely from its jaws and teeth, thus postcraneal elements are deduced based on the relatively similar hog-nosed skunks, but as a more robust form.^[5] The holotype, USNM 12045, is a damaged lower jaw that meassures 3 cm (1.2 in) long.^[6] Brachyprotoma obtusata's jaw is considered to possess several primitive characteristics, such as the large size of Premolar

^{4} and Molar^{1} , the large size of the anterior premolars, the smaller protocone in P^{4} , the weaker metaconid in M^{1} and the transverse elongation of M^{1} ;^[7] and some more derived traits, B. obtusata has two upper and three lower premolars, having gotten rid of the anterior-most premolars.^[8]

Etymology and Phylogeny

The generic name Brachyprotoma, from the greek Brachy, meaning short; and Protomē, the head and neck of a decapitated animal; in reference to the holotype's robust appearance aswell as the curious lack of post-craneal remains. The specific name obtusata hails from the latin Obtusitas, meaning dense.

The precise phylogenic relationships of Brachyprotoma within Mephitidae remain controversial, it shares a dental formula with Promephitis hootoni, while its P

^{4} shares more characteristics with those in the genus mephitis. As of Wang et. al. 2005,^[9] Brachyprotoma obtusata was recovered as a more derived skunk:

Extinction

It is unclear why Brachyprotoma obtusata went extinct along with the North American megafauna, there are several present specimens in the Bonneville Basin, Utah, circa 24.000 to 18.000 years ago. However, the species is absent in more recent strata; where only generalists remain, suggesting some degree of specialization in Brachyprotoma obtusata, perhaps related to the megafuana itslef.

Notes and References

1. Harington . C. R. . 1978 . Quaternary vertebrate faunas of Canada and Alaska and their suggested chronological sequence . Syllogeus . 15 . 1–105.
2. Grady . F. . Garton . E. R. . 2000 . Paleontology and historic field trip of the John Guilday Cave Preserve (Trout Rock). . The Caves of East-central West Virginia . 14 . 241–244.
3. Youngman. Phillip M.. The extinct short-faced skunk Brachyprotoma obtusata (Mammalia, Carnivora): first records for Canada and Beringia. Canadian Journal of Earth Sciences. 1986. 23. 2. 419–424. 10.1139/e86-043. 1986CaJES..23..419Y .
4. Cope, Edward D. (1899). "Vertebrate remains from Port Kennedy bone deposit". Journal of the Academy of Natural Sciences of Philadelphia. Ser. 2. 11 (2): 236–237.
5. Wang . Xiaoming . Carranza-Castañeda . Óscar . October 2008 . Earliest hog-nosed skunk, Conepatus (Mephitidae, Carnivora), from the early Pliocene of Guanajuato, Mexico and origin of South American skunks . Zoological Journal of the Linnean Society . en . 154 . 2 . 386–407 . 10.1111/j.1096-3642.2008.00411.x.
6. Web site: Emslie . Steven D. . 2012 . Paleoecology of the Upper Gunnison Basin, Colorado . 2024-05-08 . UNCW Emslie Lab.
7. Pilgrim . G. E. . 1933 . A fossil skunk from Samos . American Museum Novitates . 663 . 13.
8. Şenyürek . Muzaffer . 1954-07-20 . A Sudy of A Skull of Promephitis from The Pontian of Küçükyozgat . Belleten . en . 18 . 71 . 279–316 . 0041-4255.
9. Wang . Xiaoming . Whistler . David P. . Takeuchi . Gary T. . 2005-12-30 . A new basal skunk Martinogale (Carnivora, Mephitinae) from Late Miocene Dove Spring Formation, California, and origin of New World mephitines . Journal of Vertebrate Paleontology . en . 25 . 4 . 936–949 . 10.1671/0272-4634(2005)025[0936:ANBSMC]2.0.CO;2 . 0272-4634.