''Microcosmodon'' is a

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

genus from the Paleocene of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. It was a member of the extinct order Multituberculata, and lies within the suborder Cimolodonta and family

Microcosmodontidae Microcosmodontidae is a poorly preserved family of fossil mammals within the extinct order Multituberculata. Representatives are known from the Lower Paleocene of North America. The family is part of the suborder Cimolodonta. Other than that, the ...

. The genus ''Microcosmodon'' was named by G.L. Jepsen in 1930.

Species

The species ''Microcosmodon arcuatus'' was named by P.A. Johnston and R.C. Fox in 1984. Fossil remains have been found in the Puercan (Paleocene)-age

strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ei ...

Rav W-1 of Saskatchewan, Canada. The holotype is in the University of Alberta collection. When alive, the creature weighed about the same as a well-fed mouse (about 30 g). The type species ''Microcosmodon conus'' was named by G.L. Jepsen in 1930. Remains have been found in the Tiffanian (Paleocene)-age strata of the Polecat Bench Formation of Wyoming (United States) and Saskatchewan, Canada. This species would have weighed around 15 g. The species ''Microcosmodon harleyi'' was named by A. Weil in 1998. Remains have been found in the Puercan (Paleocene)-age strata of the Tullock Formation in Montana (USA). "The presence of the new species suggests that microcosmodontine species richness in the Western Interior was as high at the beginning of the Paleocene as at its end," (Weil, 1998). The species would have weighed about 20 g. The species ''Microcosmodon rosei'' was named by D.W. Krause in 1980. Remains have been found in the Clarforkian (Paleocene)-age strata of the Willwood Formation of Wyoming. This species weighed a fairly standard mouse-sized 25 g+. The species ''Microcosmodon woodi'' was named by R.C. Holtzman and D.L. Wolberg in 1977. It is also known as ''Eucosmodontid woodi'' (Weil 1998). Remains have been found in the Middle Paleocene-age strata of Montana and North Dakota (USA) and Alberta, Canada. However, Weil A. (1998) found that this material "does not belong to this genus or subfamily."

References

* Weil (1998), "A new species of ''Microcosmodon'' (Mammalia: Multituberculata) from the Paleocene Tullock Formation of Montana, and an argument for the Micrcosmodontinae". ''PaleoBios'' 18. * Krause (1980), "Multituberculates from the Clarkforkian Land-Mammal Age, late Paleocene-early Eocene, of western North America". ''J. Paleont.'' 54(6), p. 1163-1183. *Jepsen (1930), "Stratigraphy and paleontology of the Paleocene of northeastern Park County, Wyoming". ''Proceedings of the American Philosophical Society'' 69(1), p. 463-528. *Holtzman & Wolberg (1977), "The Microsmodontinae and ''Microcosmodon woodi'', new Multituberculata taxa (Mammalia) from the Late Paleocene of North America". ''Sci. Publ. of the Sci. Mus. of Minnesota'' 4(1), p. 1-13. *Kielan-Jaworowska Z & Hurum JH (2001), "Phylogeny and Systematics of multituberculate mammals". ''Palaeontology'' 44, p. 389-429. *Johnston & Fox (1984), "Paleocene and Late Cretaceous mammals from Saskatchewan, Canada". Palaeontogr. Abt. A: Paläozool., Stratigr. 186, p. 163-222. *Much of this information has been derived fro

MESOZOIC MAMMALS:

Eucosmodontidae Eucosmodontidae is a poorly preserved family of fossil mammals within the extinct order Multituberculata. Representatives are known from strata dating from the Upper Cretaceous through the Lower Eocene of North America, as well as the Paleocene ...

and Taeniolabidoidea, an Internet directory. {{Taxonbar, from=Q767786 Cimolodonts Paleocene mammals Paleocene genus extinctions Extinct mammals of North America Prehistoric mammal genera