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.[2]
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 12 in (30 cm) and may have resembled a modern opossum.[3] 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.[4][3]
The type species is Alphadon marshi. Eight other species are known.[2]
The species Alphadon jasoni was originally described by Storer (1991);[5] it was subsequently transferred to the herpetotheriid genus Nortedelphys.[6]
Recent phylogenetic studies group it with other northern non-marsupial metatherians such as Albertatherium and Turgidodon.[7][8] A 2016 phylogenetic analysis is shown below.[9]
^J. G. Eaton. 1993. Therian mammals from the Cenomanian (Upper Cretaceous) Dakota Formation, southwestern Utah. Journal of Vertebrate Paleontology 13(1):105-124
^ abcHaaramo, Mikko (August 2003). "Alphadontidae". Mikko's Phylogeny Archive.
^Montellano, Marisol (1988). "Alphadon halleyi (Didelphidae, Marsupialia) from the Two Medicine Formation (Late Cretaceous, Judithian) of Montana". Journal of Vertebrate Paleontology. 8 (4): 378–382. doi:10.1080/02724634.1988.10011726.
^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.
^Thomas E. Williamson; Stephen L. Brusatte; Thomas D. Carr; Anne Weil; Barbara R. Standhardt (2012). "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. doi:10.1080/14772019.2011.631592.
^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.
^S. Bi, X. Jin, S. Li and T. Du. 2015. A new Cretaceous metatherian mammal from Henan, China. PeerJ 3:e896
