Bryceomys is an extinct 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...

 that lived during the late 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...

 period (between 100 and 65 million years ago) and thus shared the world with dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

s. It was a member of the also 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...

. It was within the suborder of 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 a member of 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....

.

The genus Bryceomys ("Bryce mouse", after Bryce Canyon National Park

Bryce Canyon National Park

Bryce Canyon National Park is a national park located in southwestern Utah in the United States. The major feature of the park is Bryce Canyon which, despite its name, is not a canyon but a giant natural amphitheater created by erosion along the eastern side of the Paunsaugunt Plateau...

) was named by Eaton J.G. in 1995.

Species

The species Bryceomys fumoses (Eaton 1995) is known from fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s found in 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...

 dating to the Turonian (Upper Cretaceous) in the Straight Cliffs Formation of 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...

, USA. They probably weighed about 12g, about half the weight of a house mouse. About a hundred teeth are held at the Oklahoma Museum of Natural History, including 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...

.

Species: Bryceomys hadrosus Eaton J.G. 1995

Place: Straight Cliffs Formation

Straight Cliffs Formation

The Straight Cliffs Formation is a Mesozoic geologic formation. Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation.-Paleofauna:* cf. Paronychodon sp....

 of Utah

Age: Turonian (Upper Cretaceous)

Also in the Oklahoma collection. Suggested bodyweight is around 90 g.

Species: Bryceomys intermedius Eaton JG & Cifelli RL, 2001

Place: Cedar Mountain Formation

Cedar Mountain Formation

The Cedar Mountain Formation is the name given to distinctive sedimentary rocks in eastern Utah that occur between the underlying Morrison Formation and overlying Naturita Formation . It is composed of non-marine sediments, that is, sediments deposited in rivers, lakes and on flood plains...

, Utah

Age: Albian (late) - Cenomanian (early) (Upper Cretaceous)