Alphadon


Alphadon (meaning "first tooth") was a 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.[1]

Alphadon
Temporal range: Late Cretaceous, 90–66.043 Ma
Reconstruction of Alphadon sp.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Family: Alphadontidae
Genus: Alphadon
Simpson, 1927
Species[1]
  • A. marshi (type)
    Simpson, 1927
  • A. wilsoni
    Lillegraven, 1969
  • A. halleyi
    Sahni, 1972
  • A. attaragos
    Lillegraven & McKenna, 1986
  • A. sahnii
    Lillegraven & McKenna, 1986
  • A. clemensi
    Eaton, 1993
  • A. lillegraveni
    Eaton, 1993
  • A. perexiguus
    Cifelli, 1994
  • A. eatoni
    Cifelli & Muizon, 1998

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 12 in (30 cm) and may have resembled a modern opossum.[2] 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 forge for food.[3][2]

Taxonomy and classification

The type species is Alphadon marshi. Eight other species are known.[1]

The species Alphadon jasoni was originally described by Storer (1991); 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]

Marsupialiformes

Gurlin Tsav skull

Borhyaenidae

Mayulestes

Jaskhadelphys

Andinodelphys

Pucadelphys

Asiatherium

Iugomortiferum

Kokopellia

Aenigmadelphys

Anchistodelphys

Glasbiidae

Glasbius

Pediomyidae

Pediomys

Stagodontidae

Pariadens

Eodelphis

Didelphodon

Alphadontidae

Turgidodon

Alphadon

Albertatherium

Marsupialia

References

  1. Haaramo, Mikko (August 2003). "Alphadontidae". Mikko's Phylogeny Archive.
  2. Jehle, Martin (August 2005). "Marsupials: A southern success story". Paleocene mammals of the world.
  3. Montellano, Marisol (1988). "Alphadon halleyi (Didelphidae, Marsupialia) from the Two Medicine Formation (Late Cretaceous, Judithian) of Montana". Journal of Vertebrate Paleontology. 8.
  4. 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.
  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. Wilson, G.P.; Ekdale, E.G.; Hoganson, J.W.; Calede, J.J.; Linden, A.V. (2016). "A large carnivorous mammal from the Late Cretaceous and the North American origin of marsupials". Nature Communications. 7: 13734. doi:10.1038/ncomms13734. PMC 5155139. PMID 27929063.