''Baiotomeus'' is a genus of mammals from the extinct order of

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 ...

. It is known from the

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

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 ...

. The

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 ...

''Baiotomeus'' was formally named by Krause in 1987 ( Krause, 1987), and has also been known as '' Mimetodon'' (partly), ''

Neoplagiaulax ''Neoplagiaulax'' is a mammal genus from the Paleocene of Europe and North America. In the case of the latter continent, there may possibly be some slightly earlier, Upper Cretaceous material too. It existed in the age immediately following the e ...

'' (partly), and ''

Ptilodus ''Ptilodus'' (meaning "soft-haired") 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 ...

'' (partly).

Species

''B. douglassi''

''Baiotomeus douglassi'' is a fairly substantial multituberculate weighing almost 200 g. Remains have been found in the

Fort Union Formation The Fort Union Formation is a geologic unit containing sandstones, shales, and coal beds in Wyoming, Montana, and parts of adjacent states. In the Powder River Basin, it contains important economic deposits of coal, uranium, and coalbed methane. ...

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 ...

and Porcupine Hills Formation of Alberta, Canada. The holotype specimen hails from

Wyoming Wyoming ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States, Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho t ...

in the United States, in strata of the Gidley Quarry dated to the

Torrejonian The Torrejonian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 63,300,000 to 60,200,000 years BP lasting . It is usually ...

stage Stage, stages, or staging may refer to: Arts and media Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly Brit ...

of the

. The species was originally named ''

douglassi'' by Simpson in 1935 ( Simpson, 1935), but it has been reclassified several times: * '' Mimetodon douglassi'' in 1940, by Jepsen * ''

douglassi'' in 1974, by Schiebout It was finally assigned to ''Baiotomeus'' by Hartman in 1986 — which is ''before'' Krause formally established the genus in 1987.

''B. lamberti''

Remains of ''Baiotomeus lamberti'' have been discovered in Montana in the United States, in the Medicine Rocks of the

Tongue River Formation The Tongue River Member is the uppermost Member (geology), geologic member of the Fort Union Formation in Montana, North Dakota, Wyoming. The strata are yellow or light-colored massive sandstones and numerous thick coal beds. The vertebrate fo ...

, which have been dated to the Paleocene. Several specimens, including the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

, are at the

Peabody Museum of Natural History The Peabody Museum of Natural History at Yale University (also known as the Yale Peabody Museum of Natural History or the Yale Peabody Museum) is one of the oldest, largest, and most prolific university natural history museums in the world. It ...

at Yale. Collected in 1958 and 1965, these were originally described as belonging to '' Mimetodon''. It was given its current name in 1987 by Krause ( Krause, 1987). ''B. lamberti'' has also been confused with ''

montanus''.

''B. russelli''

''Baiotomeus russelli'' has been discovered in

Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...

, Canada, in Cochrane 2 of the

Paskapoo Formation The Paskapoo Formation is a stratigraphic unit of Middle to Late Paleocene age in the Western Canada Sedimentary Basin. The Paskapoo underlies much of southwestern Alberta, and takes the name from the Blindman River ( means 'He is blind' in Cr ...

, which has been dated to the lower

Tiffanian The Tiffanian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 60,200,000 to 56,800,000 years BP lasting . It is usually co ...

stage of the Paleocene. Remains consist of nine upper pre

molars The molars or molar teeth are large, flat tooth, teeth at the back of the mouth. They are more developed in mammal, mammals. They are used primarily to comminution, grind food during mastication, chewing. The name ''molar'' derives from Latin, '' ...

, (P4), which average nearly 2.5 mm in length. This is smaller than the teeth of other genus members; from front to back, approximately 45% less than ''B. douglassi'' and 40% less than ''B. lamberti''. The rows of cusps also display a strong curvature and the cuspate anterolabial lobe is better developed. There is more variation in the height of the cusps among the middle row. These particular premolars — P4s — have three rows of cusps, of which there seem to be about 15 or so in all. In addition, "the enamel is weakly wrinkled on all specimens". ( Scott ''et al.'', 2002) According to the same authors: :At present, P4s are the only specimens from Cochrane 2 that we can identify as pertaining to ''B. russelli''. Although knowledge of this species is limited, we consider its naming to be justified based on the diagnostic morphology of ultimate fourth premolars in ptilodontids generally (Krause 1982, 1987) and the unique structure of these teeth. The species name honours L. S. Russell "for his pioneering research on the mammals from Cochrane 2". All presently identified remains are part of 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 ...

. Cochrane 2 has also been interpreted as correlating to the Porcupine Hills Formation, but recent studies suggest that it is part of the Paskapoo, as originally concluded by Russell in 1929.

References

Bibliography

* Z. Kielan-Jaworowska and J. H. Hurum. (2001) "Phylogeny and Systematics of multituberculate mammals." ''Paleontology'' 44, pg. 389–429. * D. W. Krause. (1987) "Baiotomeus, a new ptilodontid multituberculate (Mammalia) from the Middle Paleocene of western North America." ''Journal of Paleontology'' 61, pg. 595–603. * Craig S. Scott, Richard C. Fox, and Gordon P. Youzwyshyn. (2002
New earliest Tiffanian (late Paleocene) mammals from Cochrane 2, southwestern Alberta, Canada
(''Warning:'' 353 KB

PDF Portable document format (PDF), standardized as ISO 32000, is a file format developed by Adobe Inc., Adobe in 1992 to present documents, including text formatting and images, in a manner independent of application software, computer hardware, ...

). ''Acta Palaeontologica Polonica'' 47(4), pg. 691–704. * G. G. Simpson (1935). "New Paleocene mammals from the Fort Union of Montana." ''Proceedings of the United States National Museum'' 83, pg. 221–244. * This information has been derived fro
MESOZOIC MAMMALS; Ptilodontoidea
an Internet directory. {{Taxonbar, from=Q730287 Ptilodontoidea Paleocene mammals Paleocene genus extinctions Paleogene mammals of North America Fossil taxa described in 1987 Prehistoric mammal genera