Alphadon

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]

Alphadon Temporal range: Late Cretaceous, 100.5–66 Ma PreꞒ Ꞓ O S D C P T J K Pg N [1]
Reconstruction of Alphadon sp.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Family:	†Alphadontidae
Genus:	†Alphadon Simpson, 1927
Species[2]
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.^[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]

Taxonomy and classification

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]

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