''Mesodma'' is an extinct
genus of
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 ...
, a member of the extinct order
Multituberculata within the suborder
Cimolodonta, family
Neoplagiaulacidae
Neoplagiaulacidae is a family of mammal within the extinct order Multituberculata. Fossil remains are known from the Upper Cretaceous through to the latest Eocene/early Oligocene. Representatives have been found in North America, Europe and Asia. ...
. It lived during the upper
Cretaceous and
Paleocene Periods of what is now
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 ...
. The earliest definitive record is from the late
Santonian
The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya (million years ago) and 83.6 ± 0.7 mya. The ...
stage strata of the
Straight Cliffs Formation. A single
premolar
The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mouth ...
tooth from the lower
Cenomanian
The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...
stage strata of the
Cedar Mountain Formation has been tentatively assigned to this genus based on its similarity, but its describers noted that it is unlikely that ''Mesodma'' lived during that time.
Species
*''Mesodma ambigua''
**Place: Mantua Lentil,
Wyoming (USA)
**Age:
Maastrichtian-Puercan, Upper Cretaceous - Paleocene
**Weight: about 55 g
*''Mesodma formosa''
**Place: Hell Creek and Frenchman Formation, USA & Canada. This species is possibly also known from
Utah.
**Age: Maastrichtian-Puercan (Upper Cretaceous to the Paleocene).
**Weight: about 30 g
*''Mesodma hensleighi''
**Place:
Hell Creek Formation in the
U.S. and in
Saskatchewan,
Canada.
**Age:
Campanian (Upper Cretaceous).
**Weight: around 15 g
*''Mesodma pygmaea''
**Place: Gidley Quarry, Montana, as well as Wyoming and Alberta, Canada
**Age: Torrejonian-Tiffanian (Middle Paleocene).
**Weight: about 8 g
*''Mesodma senecta''
**Age: Campanian (Upper Cretaceous)
**Weight: about 50 g
*''Mesodma thompsoni'' (=''M. garfieldensis'')
**Place: St Mary River Formation & Montana and Wyoming of the US and Canada
**Age: Maastrichtian-Puercan, Upper Cretaceous - Paleocene
**Weight: about 55 g
The species ''"Mesodma" primaeva'' from the
Judithian
The Judithian was a North American faunal stage lasting from 83.5 to 70.6 million years ago. It overlaps with the Campanian global stage.
Fauna
Dinosaur faunas of the Judithian age may represent the peak of dinosaur evolution in North America. H ...
of Western Interior of North America was formerly assigned to the genus ''Mesodma'', but subsequently it was made the
type species of a separate genus ''
Filikomys''.
References
Further reading
*Osborn (1891); "A review of the Cretaceous Mammalia". ''Proc. Acad. Nat. Sci. Phila.'' 124 - 135.
*Simpson (1929), "American Mesozoic Mammalia". Mem. Peabody Mus. Nat. Hist. iii (i): p. 1-235.
*Clemens (1963), "Fossil mammals of the type Lance formation Wyoming. Part I. Introduction and Multituberculata". Univ. Calif. Pub;. ''Geol. Sci.'' 48, p. 1-105. (According to Peabody Museum database.)
*Marsh (1889), "Discovery of Cretaceous Mammalia". ''Am. J. Sci.'' (3) xxxviii, p. 177-180.
*Archibald (1982), ''A study of Mammalia and geology across the Cretaceous-Tertiary boundary in Garfield County, Montana''. Univ. of Calif. Publ. Geol. Sci. 122xvi+, 286pp.
*Jepsen (1940), "Paleocene faunas of the Polecat Bench formation, Park County, Wyoming". ''Pro. Amer. Philos. Soc'' 83, p. 217-341, 21 figs., 5 pls.
*
{{Taxonbar, from=Q16985422
Ptilodontoids
Paleocene genus extinctions
Cretaceous mammals of North America
Paleocene mammals of North America
Ojo Alamo Formation
Milk River Formation
Hell Creek fauna
Prehistoric mammal genera