Alphadon Explained

Alphadon is an extinct genus of small, primitive mammal that was a member of the metatherians, a group of mammals that includes modern-day marsupials. Its fossils were first discovered and named by George Gaylord Simpson in 1929.

Description

Not much is known about the appearance of Alphadon, as it is only known from teeth, a lower jaw and skull fragments. It probably grew to about 12inches and may have resembled a modern opossum.^[1] Judging from its teeth, it was likely an omnivore, feeding on fruits, invertebrates and possibly small vertebrates. Alphadon had a very good sense of smell and sight to track down its food, both during the day and night. Its possible whiskers could have also aided in its search for food.^{[2] [1]}

Taxonomy and classification

The type species is Alphadon marshi. Eight other species are known.The species Alphadon jasoni was originally described by Storer (1991);^[3] it was subsequently transferred to the herpetotheriid genus Nortedelphys.^[4]

Recent phylogenetic studies group it with other northern non-marsupial metatherians such as Albertatherium and Turgidodon.^{[5] [6]} A 2016 phylogenetic analysis is shown below.^[7]

Notes and References

1. Web site: Jehle . Martin . Marsupials: A southern success story . Paleocene mammals of the world . August 2005 .
2. Alphadon halleyi (Didelphidae, Marsupialia) from the Two Medicine Formation (Late Cretaceous, Judithian) of Montana . Journal of Vertebrate Paleontology . 1988 . 8 . 4 . 378–382 . Marisol . Montellano. 10.1080/02724634.1988.10011726 .
3. Storer, J.E. (1991). The mammals of the Gryde local fauna, Frenchman Formation (Maastrichtian: Lancian), Saskatchewan. Journal of Vertebrate Paleontology, vol. 11, no. 3, p. 350-396.
4. Thomas E. Williamson . Stephen L. Brusatte . Thomas D. Carr . Anne Weil . Barbara R. Standhardt . The phylogeny and evolution of Cretaceous–Palaeogene metatherians: cladistic analysis and description of new early Palaeocene specimens from the Nacimiento Formation, New Mexico . Journal of Systematic Palaeontology . 10 . 4 . 625–651 . 2012 . 10.1080/14772019.2011.631592 .
5. Guillermo W. Rougier; Brian M. Davis; Michael J. Novacek (2015). "A deltatheroidan mammal from the Upper Cretaceous Baynshiree Formation, eastern Mongolia". Cretaceous Research. 52, Part A: 167–177. doi:10.1016/j.cretres.2014.09.009.
6. S. Bi, X. Jin, S. Li and T. Du. 2015. A new Cretaceous metatherian mammal from Henan, China. PeerJ 3:e896
7. A large carnivorous mammal from the Late Cretaceous and the North American origin of marsupials . Nature Communications . 7 . 13734 . 2016 . G.P. . Wilson . E.G. . Ekdale . J.W. . Hoganson . J.J. . Calede . A.V.. Linden . 10.1038/ncomms13734 . 27929063 . 5155139 .