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Baiotomeus | |
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Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | † Multituberculata |
Family: | † Ptilodontidae |
Genus: | † Baiotomeus |
Species | |
B. douglassi |
Baiotomeus is a genus of mammals from the extinct order of Multituberculata. It is known from the Paleocene of North America.
The genus Baiotomeus was formally named by Krause in 1987 (Krause, 1987), and has also been known as Mimetodon (partly), Neoplagiaulax (partly), and Ptilodus (partly).
Baiotomeus douglassi is a fairly substantial multituberculate weighing almost 200 g. Remains have been found in the Fort Union Formation of Montana and Porcupine Hills Formation of Alberta, Canada. The holotype specimen hails from Wyoming in the United States, in strata of the Gidley Quarry dated to the Torrejonian stage of the Paleocene.
The species was originally named Ptilodus douglassi by Simpson in 1935 (Simpson, 1935), but it has been reclassified several times:
It was finally assigned to Baiotomeus by Hartman in 1986 — which is before Krause formally established the genus in 1987.
Remains of Baiotomeus lamberti have been discovered in Montana in the United States, in the Medicine Rocks of the Tongue River Formation, which have been dated to the Paleocene.
Several specimens, including the holotype, are at the Peabody Museum of Natural History 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 Ptilodus montanus.
Baiotomeus russelli has been discovered in Alberta, Canada, in Cochrane 2 of the Paskapoo Formation, which has been dated to the lower Tiffanian stage of the Paleocene.
Remains consist of nine upper premolars, (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:
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.
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.
Multituberculata is an extinct taxon of rodent-like allotherian mammals that existed for approximately 166 million years, the longest fossil history of any mammal lineage. They eventually declined from the late Paleocene onwards, disappearing from the known fossil record in the late Eocene, though gondwanatheres lived into the Miocene, and may have been multituberculates. More than 200 species are known, ranging from mouse-sized to beaver-sized. These species occupied a diversity of ecological niches, ranging from burrow-dwelling to squirrel-like arborealism to jerboa-like hoppers. Multituberculates are usually placed as crown mammals outside either of the two main groups of living mammals—Theria, including placentals and marsupials, and Monotremata—but closer to Theria than to monotremes. Nonetheless, at least one study found a potential status as sister taxa to monotremes/Australosphenida.
Ptilodus is a genus of mammals from the extinct order of Multituberculata, and lived during the Paleocene in North America.
Cimolodonta is 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. The more basal multituberculates are found in a different suborder, "Plagiaulacida".
Catopsalis is a genus of extinct mammal from the Paleocene of North America. This animal was a relatively large member of the extinct order of Multituberculata. Most Multituberculates were much smaller.
Taeniolabis is a genus of extinct multituberculate mammal from the Paleocene of North America.
Neoliotomus is a genus of North American mammal from the Paleocene. It existed in the age immediately following the extinction of the last dinosaurs and was a member of the extinct order Multituberculata. It lies within the suborder Cimolodonta and the superfamily Ptilodontoidea. Other than that, its affinities are somewhat unclear.
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 extinction of the last dinosaurs. This animal was a member of the extinct order Multituberculata, lying within the suborder Cimolodonta and family Neoplagiaulacidae.
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.
Mimetodon is a small mammal from the Paleocene of North America and perhaps Europe. It was a member of the extinct order Multituberculata within the suborder Cimolodonta and family Neoplagiaulacidae.
Parectypodus is an extinct genus of mammals that lived from Late Cretaceous (Maastrichtian) to Eocene time in North America. It is a member of the extinct order of Multituberculata, suborder Cimolodonta, family Neoplagiaulacidae. It was named by G.L. Jepsen in 1930.
Ptilodontidae is a family of primitive mammals within the extinct order Multituberculata. Representatives are known from the Upper Cretaceous and Paleocene of North America.
Prochetodon is a genus of mammals from the extinct order Multituberculata. It lived during the Upper Paleocene and the Lower Eocene in North America. The genus was formally named by G. L. Jepsen in 1940.
Anconodon is an extinct genus of mammal from the Paleocene of North America, and thus lived just after the "age of the dinosaurs". It was a member of the extinct order Multituberculata within the suborder Cimolodonta and possibly the family Cimolodontidae.
Stygimys is an extinct mammal genus from the Upper Cretaceous and Paleocene of North America. It was a member of the extinct order Multituberculata within the suborder Cimolodonta, family Eucosmodontidae.
Microcosmodon is a mammal genus from the Paleocene of North America. It was a member of the extinct order Multituberculata, and lies within the suborder Cimolodonta and family Microcosmodontidae. The genus Microcosmodon was named by G.L. Jepsen in 1930.
Ferugliotherium is a genus of fossil mammals in the family Ferugliotheriidae from the Campanian and/or Maastrichtian period of Argentina. It contains a single species, Ferugliotherium windhauseni, which was first described in 1986. Although originally interpreted on the basis of a single brachydont (low-crowned) molar as a member of Multituberculata, an extinct group of small, rodent-like mammals, it was recognized as related to the hypsodont (high-crowned) Sudamericidae following the discovery of additional material in the early 1990s. After a jaw of the sudamericid Sudamerica was described in 1999, these animals were no longer considered to be multituberculates and a few fossils that were previously considered to be Ferugliotherium were assigned to unspecified multituberculates instead. Since 2005, a relationship between gondwanatheres and multituberculates has again received support. A closely related animal, Trapalcotherium, was described in 2009 on the basis of a single tooth.
Ferugliotheriidae is one of three known families in the order Gondwanatheria, an enigmatic group of extinct mammals. Gondwanatheres have been classified as a group of uncertain affinities or as members of Multituberculata, a major extinct mammalian order. The best-known representative of Ferugliotheriidae is the genus Ferugliotherium from the Late Cretaceous epoch in Argentina. A second genus, Trapalcotherium, is known from a single tooth, a first lower molariform, from a different Late Cretaceous Argentinean locality. Another genus known from a single tooth, Argentodites, was first described as an unrelated multituberculate, but later identified as possibly related to Ferugliotherium. Finally, a single tooth from the Paleogene of Peru, LACM 149371, perhaps a last upper molariform, and a recent specimen from Mexico, may represent related animals.
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. It was first described from outcrops along that river, near its confluence with the Red Deer River north of the city of Red Deer, by J.B. Tyrrell in 1887. It is important for its freshwater aquifers, its coal resources, and its fossil record, as well as having been the source of sandstone for the construction of fire-resistant buildings in Calgary during the early 1900s.
The Coalspur Formation is an Upper Cretaceous to lower Palaeocene stratigraphic unit of the Western Canada Sedimentary Basin in the foothills of southwestern Alberta. Its deposition spanned the time interval from latest Cretaceous (Maastrichtian) to early Palaeocene, and it includes sediments that were deposited before, during, and after the Cretaceous-Paleogene (K-Pg) extinction event. It includes the economically important coal deposits of the Coalspur Coal Zone, as well as nonmarine plant and animal fossils.
Gypsonictops is an extinct genus of leptictidan mammals of the monotypic family Gypsonictopidae, which was described in 1927 by George Gaylord Simpson. Species in this genus were small mammals and the first representatives of the order Leptictida, that appeared during the Upper Cretaceous.