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

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 12 in (30 cm) and may have resembled a modern opossum. 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.

Taxonomy and classification

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

Recent phylogenetic studies group it with other northern non-marsupial metatherians such as Albertatherium and Turgidodon. A 2016 phylogenetic analysis is shown below.

References

1. J. G. Eaton. 1993. Therian mammals from the Cenomanian (Upper Cretaceous) Dakota Formation, southwestern Utah. Journal of Vertebrate Paleontology 13(1):105-124
2. ^ Haaramo, Mikko (August 2003). "Alphadontidae". Mikko's Phylogeny Archive.
3. ^ Jehle, Martin (August 2005). "Marsupials: A southern success story". Paleocene mammals of the world.
4. 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.
5. 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.
6. 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.
7. 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.
8. S. Bi, X. Jin, S. Li and T. Du. 2015. A new Cretaceous metatherian mammal from Henan, China. PeerJ 3:e896
9. 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.

v t e Metatheria
Kingdom: Animalia Phylum: Chordata Class: Mammalia Subclass: Theria Synapsida see Synapsida Cynodontia see Cynodontia Mammalia see Mammalia Metatheria see below↓
Metatheria Metatheria †Adinodon †Archaeonothos †Esteslestes †Ghamidtherium †Holoclemensia? †Kasserinotherium †Protalphadon †Sinodelphys? †Deltatheroida Pappotherium? Deltatheridiidae Atokatheridium? Deltatheridium Deltatheroides Gurbanodelta Lotheridium Nanocuris Oklatheridium? Prodeltitheridium Sulestes Tsagandelta Marsupialiformes †Adelodelphys †Aenigmadelphys †Anchistodelphys †Andinodelphys †Arcantiodelphys †Camptomus? †Glasbius †Gurlin Tsav skull †Iugomortiferum †Jaskhadelphys †Mayulestes †Pucadelphys †Sinbadelphys †Sparassodonta see below↓ †Asiatheriidae Asiatherium Kokopellia †Archimetatheria Iqualadelphis Stagodontidae Didelphodon Eobrasilia? Eodelphis Fumodelphodon Hoodootherium Pariadens? Pediomyoidea Aquiladelphis Austropediomys Dakotadens Monodelphopsis Pediomys Protolambda Scalaridelphys Unnuakomys †Peradectidae Armintodelphys Didelphidectes Mimoperadectes Nanodelphys Peradectes Siamoperadectes †Alphadontidae Albertatherium Alphadon Eoalphadon Turgidodon †Herpetotheriidae Amphiperatherium Asiadidelphis Copedelphys Ectocentrocristus Entomacodon Galatiadelphys Golerdelphys Herpetotherium Indodelphis Maastrichtidelphys Morotodon? Nortedelphys Peratherium Rumiodon? Swaindelphys Thylacodon †Anatoliadelphyidae Anatoliadelphys Orhaniyeia †Polydolopimorphia see below↓ Marsupialia Ameridelphia Didelphimorphia Paucituberculata Australidelphia
Sparassodonta Sparassodonta Allqokirus Argyrolestes Hondadelphys Nemolestes Patene Procladosictis Stylocynus Hathliacynidae Acyon Australogale Borhyaenidium Chasicostylus Cladosictis Notictis Notocynus Notogale Perathereutes Pseudonotictis Sallacyon Sipalocyon Borhyaenoidea Angelocabrerus Chlorocyon Dukecynus Fredszalaya Lycopsis Pharsophorus Plesiofelis Prothylacinus Pseudolycopsis Pseudothylacynus Borhyaenidae Acrocyon Arctodictis Australohyaena Borhyaena Eutemnodus? Proborhyaenidae Arminiheringia Callistoe Paraborhyaena Proborhyaena Thylacosmilidae Anachlysictis Eomakhaira Patagosmilus Thylacosmilus
Polydolopimorphia Polydolopimorphia Apeirodon? Bobbschaefferia Caroloameghinia Carolocoutoia Guggenheimia Gashternia Hatcheritherium Palangania Procaroloameghinia Protodidelphis Pujatodon? Reigia Robertbutleria Wamradolops Zeusdelphys Bonapartheriiformes Bonapartheriidae Bonapartherium Epidolops Argyrolagidae Anargyrolagus Argyrolagus Hondalagus Microtragulus Proargyrolagus Chulpasiinae Chulpasia Thylacotinga Prepidolopidae Incadolops Perrodelphys Prepidolops Punadolops Seumandia Rosendolopidae Hondonadia Rosendolops Polydolopiformes Polydolopidae Amphidolops Antarctodolops Eudolops Eurydolops Hypodolops Kramadolops Parabderites Polydolops Pseudolops Sillustaniidae Roberthoffstetteria Sillustania

• Prehistoric metatherians
• Late Cretaceous mammals of North America
• Hell Creek fauna
• Milk River Formation
• Fossil taxa described in 1927