''Paracimexomys'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of extinct

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s in the extinct

Multituberculata Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct Order (biology), order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the M ...

order. ''Paracimexomys'' lived during the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

period. The few fossils remains come from

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. Some

Romania Romania is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern and Southeast Europe. It borders Ukraine to the north and east, Hungary to the west, Serbia to the southwest, Bulgaria to the south, Moldova to ...

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

s were also tentatively assigned to this

, though that classification now seems doubtful. The genus ''Paracimexomys'' ("beside ''

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 ...

''") was named by Archibald J.D. in 1982. ''Paracimexomys''

s were originally referred to as ''Cimexomys'', until it was realized they were different enough to justify a genus of their own.

Species

* ''Paracimexomys magister'' also known as ''Cimexomys magister''- Remains were found in the Upper

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 m ...

(Upper Cretaceous) of

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

, USA. The animal probably weighed about 100g when it was alive. * ''Paracimexomys magnus'' also known as ''Cimexomys magnus''- were found in the

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

(Upper Cretaceous) strata of the Judith River Formation in

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

, USA. * ''Paracimexomys priscus''- Fossil remains were found in the

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

(Upper Cretaceous) of Hell Creek, Montana. Remains were first found in 1966. The holotype is in the collection of the

University of Alberta The University of Alberta (also known as U of A or UAlberta, ) is a public research university located in Edmonton, Alberta, Canada. It was founded in 1908 by Alexander Cameron Rutherford, the first premier of Alberta, and Henry Marshall Tory, t ...

, where the name ''Cimexomys'' is favoured. Weight is estimated to have been 60g.

Misassigned species

* ''Paracimexomys crossi''- Remains have been found in the Middle Cretaceous (Upper

Aptian The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...

to lower

Albian The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...

)

Antlers Formation The Antlers Formation is a stratum which ranges from Arkansas through southern Oklahoma into northeastern Texas. The stratum is thick consisting of silty to sandy mudstone and fine to coarse grained sandstone that is poorly to moderately sorted. ...

Oklahoma Oklahoma ( ; Choctaw language, Choctaw: , ) is a landlocked U.S. state, state in the South Central United States, South Central region of the United States. It borders Texas to the south and west, Kansas to the north, Missouri to the northea ...

, USA. Based on a tiny tooth, this was the first reported Oklahoma Mesozoic mammal. It's also the oldest known member of the informal Paracimexomys group. The species' name honours the prison officer Bobby Cross, who has found this and other fossils. * ''Paracimexomys perplexus''- Found in the late

to early

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

(Upper Cretaceous) in the Cedar Mountain Formation of Utah. * ''Paracimexomys robisoni''- Found in the Middle Cretaceous strata of the Cedar Mountain Formation of Utah. This type of fossil can be found in the Oklahoma Museum of Natural History. This mouse-sized animal weighed about 25g. * ''Paracimexomys bestia'' is now the type species of ''

Cedaromys ''Cedaromys'' ("Cedar mouse") is an extinct mammal which lived during the Upper Cretaceous, at the same time as many dinosaurs. It was a member of the also extinct order of Multituberculata. It's within the suborder of Cimolodonta, and a possible ...

''.

Species

Misassigned species

References

Further reading