Cimolodon
Encyclopedia
Cimolodon is a genus of mammal
from the Upper Cretaceous
of North America
. It was a member of the extinct order of Multituberculata
within the suborder Cimolodonta
and possibly the family Cimolodontidae
.
The genus Cimolodon was named by Othniel Charles Marsh
in 1889. It is also known as Allacodon (partly); Cimolomys
(partly); Halodon (Marsh 1889); Nanomys ("small mouse") (Marsh 1889); nomyops (Marsh 1892); Ptilodus
(partly). While some Cimolomys material has indeed been referred to Cimolodon, that doesn't necessarily mean that the whole genus or a particular species has. It could well be that one-time Cimolodon fossils have subsequently also been referred to Cimolomys as well.
"Cimolodon seems to be more closely related to the Paracimexomys group
than are other ptilodontoideans," (Kielan-Jaworowska & Hurum, 2001, p.404). Odd as it may sound, the placement of this genus within Cimolodontidae is tentative. Its tooth enamel is gigantoprismatic, while its possible relatives favor a microprismatic style (p.418 ibid.).
of the Upper Milk River Formation in Alberta
, Canada
. The holotype
is in the collection of the University of Alberta
. Possible finds have been reported from New Mexico
. Weight is estimated at 19g, about half the weight of a modern rat
.
Cimolodon nitidus (Marsh O.C. 1889) is also known as Allacodon lentus (Marsh 1889); Allacodon rarus (Marsh 1892); Cimolomys
bellus (Marsh 1889); Cimolomys digona (Marsh 1899); Cimolomys gracilis (Marsh 1889); Cimolomys minutes; Cimolomys nitidus; Halodon serratus (Marsh 1889); Nanomyops minitus (Marsh 1892); Nanomys minitus (Marsh 1889); and Ptilodus
serratus (Gidley 1909). It is known from Upper Cretaceous strata
of the Lance Formation of Wyoming
, Utah
, Montana
and South Dakota
(USA and Canada
). It weighed about 230 g. Simpson referred this species to C. gracilis in 1929. Subsequently, it has been reallocated to C. nitidus by various authors, apparently beginning with Clemens in 1963.
Cimolodon pervus (Marsh O.C. 1892) is also known from the Upper Cretaceous Lance Formation of Wyoming. This species was first tentatively referred to as P. cf. carvus, (Krause, 1980). It had a weight of about 190 g.
Cimolodon similis (Fox R.C. 1971) is known from the Upper Cretaceous of Utah. This holotype
is also in the University of Alberta. It had a body weight around 125 g, about five standard mice.
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...
from 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...
of 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...
. It was a member of the extinct order of 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...
and possibly the family Cimolodontidae
Cimolodontidae
Cimolodontidae is a family of fossil mammals within the extinct order Multituberculata. Representatives are known from the Upper Cretaceous and Paleocene of North America. There is some doubt as to whether Cimolodon is within this taxon. If not, the name of the family would still be valid...
.
The genus Cimolodon was named by Othniel Charles Marsh
Othniel Charles Marsh
Othniel Charles Marsh was an American paleontologist. Marsh was one of the preeminent scientists in the field; the discovery or description of dozens of news species and theories on the origins of birds are among his legacies.Born into a modest family, Marsh was able to afford higher education...
in 1889. It is also known as Allacodon (partly); 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...
(partly); Halodon (Marsh 1889); Nanomys ("small mouse") (Marsh 1889); nomyops (Marsh 1892); Ptilodus
Ptilodus
Ptilodus 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...
(partly). While some Cimolomys material has indeed been referred to Cimolodon, that doesn't necessarily mean that the whole genus or a particular species has. It could well be that one-time Cimolodon fossils have subsequently also been referred to Cimolomys as well.
"Cimolodon seems to be more closely related to the Paracimexomys group
Paracimexomys group
The Paracimexomys group is a loose grade of extinct mammals which are known from the Lower Cretaceous and possibly through to the Paleocene of North America.They were members of an also extinct order called Multituberculata....
than are other ptilodontoideans," (Kielan-Jaworowska & Hurum, 2001, p.404). Odd as it may sound, the placement of this genus within Cimolodontidae is tentative. Its tooth enamel is gigantoprismatic, while its possible relatives favor a microprismatic style (p.418 ibid.).
Species
Cimolodon electus (Fox R.C. 1971) is known from the Upper CretaceousCretaceous
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...
of the Upper Milk River Formation in Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
, Canada
Canada
Canada 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...
. The holotype
Holotype
A 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...
is in the collection of the University of Alberta
University of Alberta
The 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...
. Possible finds have been reported from New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
. Weight is estimated at 19g, about half the weight of a modern rat
Rat
Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...
.
Cimolodon nitidus (Marsh O.C. 1889) is also known as Allacodon lentus (Marsh 1889); Allacodon rarus (Marsh 1892); 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...
bellus (Marsh 1889); Cimolomys digona (Marsh 1899); Cimolomys gracilis (Marsh 1889); Cimolomys minutes; Cimolomys nitidus; Halodon serratus (Marsh 1889); Nanomyops minitus (Marsh 1892); Nanomys minitus (Marsh 1889); and Ptilodus
Ptilodus
Ptilodus 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...
serratus (Gidley 1909). It is known from Upper Cretaceous strata
Stratum
In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers...
of the Lance Formation of Wyoming
Wyoming
Wyoming 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...
, Utah
Utah
Utah 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...
, Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
and South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
(USA and Canada
Canada
Canada 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...
). It weighed about 230 g. Simpson referred this species to C. gracilis in 1929. Subsequently, it has been reallocated to C. nitidus by various authors, apparently beginning with Clemens in 1963.
Cimolodon pervus (Marsh O.C. 1892) is also known from the Upper Cretaceous Lance Formation of Wyoming. This species was first tentatively referred to as P. cf. carvus, (Krause, 1980). It had a weight of about 190 g.
Cimolodon similis (Fox R.C. 1971) is known from the Upper Cretaceous of Utah. This holotype
Holotype
A 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...
is also in the University of Alberta. It had a body weight around 125 g, about five standard mice.