Mesodma
Encyclopedia
Mesodma is an extinct genus
of mammal
, a member of the extinct order Multituberculata
within the suborder Cimolodonta
, family Neoplagiaulacidae
. It lived during the upper Cretaceous
and Paleocene
Periods of what is now North America
. This genus has been the subject of much revision, and has also been known in part as Cimexomys
, Cimolomys
, Halodon, Parectypodus
, and Ptilodon.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
, a member of the extinct order Multituberculata
Multituberculata
The Multituberculata were a group of rodent-like mammals that existed for approximately one hundred and twenty million years—the longest fossil history of any mammal lineage—but were eventually outcompeted by rodents, becoming extinct during the early Oligocene. At least 200 species are...
within the suborder Cimolodonta
Cimolodonta
The Cimolodonta are a taxon of extinct mammals that lived from the Cretaceous to the Eocene. They were some of the more derived members of the extinct order Multituberculata. They probably lived something of a rodent-like existence until their ecological niche was assumed by true rodents...
, family Neoplagiaulacidae
Neoplagiaulacidae
Neoplagiaulacidae is a family of mammal within the extinct order Multituberculata. Fossil remains are known from the Upper Cretaceous through the Eocene. Representatives have been found in North America, Europe and Asia....
. It lived during the upper Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
and Paleocene
Paleocene
The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...
Periods of what is now North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. This genus has been the subject of much revision, and has also been known in part as Cimexomys
Cimexomys
Cimexomys is an extinct North American mammal that lived from the Upper Cretaceous to the Paleocene. For a while, it shared the world with dinosaurs, but outlived them. It was a member of the extinct order Multituberculata and lies within the suborder Cimolodonta...
, Cimolomys
Cimolomys
Cimolomys is a mammal genus from the Upper Cretaceous of North America. It was a member of the extinct order Multituberculata within the suborder Cimolodonta and family Cimolomyidae.The genus Cimolomys was named by Othniel Charles Marsh in 1889...
, Halodon, Parectypodus
Parectypodus
Parectypodus is a genus of extinct mammal that lived from the Paleocene to the Eocene of North America. Some of the known fossil material may also be from the Upper Cretaceous. It was named by G.L. Jepsen in 1930....
, and Ptilodon.
List of Species, location of discovery
- Mesodma hensleighi The holotypeHolotypeA holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
s for this species are in the collection of the University of AlbertaUniversity of AlbertaThe University of Alberta is a public research university located in Edmonton, Alberta, Canada. Founded in 1908 by Alexander Cameron Rutherford, the first premier of Alberta and Henry Marshall Tory, its first president, it is widely recognized as one of the best universities in Canada...
.- Place: Hell Creek FormationHell Creek FormationThe Hell Creek Formation is an intensely-studied division of Upper Cretaceous to lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana...
in the U.S.United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
and in SaskatchewanSaskatchewanSaskatchewan is a prairie province in Canada, which has an area of . Saskatchewan is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, and on the south by the U.S. states of Montana and North Dakota....
, CanadaCanadaCanada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. - Age: Campanian (Upper Cretaceous).
- Weight: around 15 g
- Place: Hell Creek Formation
- Mesodma ambigua, cited as a possible descendant of M. thompsoni.
- Place: Mantua Lentil, WyomingWyomingWyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
(USA) - Age: Maastrichtian-Puercan, Upper Cretaceous - Paleocene
- Weight: about 55 g
- Place: Mantua Lentil, Wyoming
- Mesodma formosa, also known as CimolomysCimolomysCimolomys is a mammal genus from the Upper Cretaceous of North America. It was a member of the extinct order Multituberculata within the suborder Cimolodonta and family Cimolomyidae.The genus Cimolomys was named by Othniel Charles Marsh in 1889...
formosus; Cimolomys gracilis; Halodon formosus; M. formosus; and Ptilodon formosus- Place: Hell Creek and Frenchman Formation, USA & Canada. This species is possibly also known from UtahUtahUtah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
. - Age: Maastrichtian-Puercan (Upper Cretaceous to the Paleocene).
- Weight: about 30 g
- Place: Hell Creek and Frenchman Formation, USA & Canada. This species is possibly also known from Utah
- Mesodma garfieldensis
- Place: Hells Hollow of Montana.
- Age: Puercan (Lower Paleocene)
- Weight: around 40 g
- Mesodma primaeva, also known as Cimolomys primaevus; ParectypodusParectypodusParectypodus is a genus of extinct mammal that lived from the Paleocene to the Eocene of North America. Some of the known fossil material may also be from the Upper Cretaceous. It was named by G.L. Jepsen in 1930....
primaeva; PtilodusPtilodusPtilodus is a genus of mammals from the extinct order of Multituberculata, and lived during the Paleocene in North America.Ptilodus was a relatively large multituberculate of in length, which is about the same size as a squirrel...
primaevus- Place: Montana and Wyoming
- Age: Campanian (Upper Cretaceous – Lower Paleocene)
- Mesodma pygmaea
- Place: Gidley Quarry, Montana, as well as Wyoming and Alberta, Canada
- Age: Torrejonian-Tiffanian (Middle Paleocene).
- Weight: about 8 g
- Mesodma senecta, a University of AlbertaUniversity of AlbertaThe University of Alberta is a public research university located in Edmonton, Alberta, Canada. Founded in 1908 by Alexander Cameron Rutherford, the first premier of Alberta and Henry Marshall Tory, its first president, it is widely recognized as one of the best universities in Canada...
holotypeHolotypeA holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
.- Age: Campanian (Upper Cretaceous)
- Weight: about 50 g
- Mesodma thompsoni, also known as Cimolodon nitidus; Cimolomys gracilis; Cimolomys nitidus
- Place: St Mary River Formation & Montana and Wyoming of the USA and Canada
- Age: Maastrichtian-Puercan, Upper Cretaceous - Paleocene
- Weight: about 55 g