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B. douglassi B. lamberti B. russelli | ||||||||||||||
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Baiotomeus is a mammal genus from the Paleocene of North America. It was a member of the extinct order of Multituberculata.
For those of a technical inclination, it's within the Suborder of Cimolodonta, family Ptilodontidae.
Genus: Baiotomeus Krause DW, 1987
Aka: Mimetodon (partly); Neoplagiaulax (partly); Ptilodus (partly)
Reference: Krause (1987), Baiotomeus, a new ptilodontid multituberculate (Mammalia) from the Middle Paleocene of western North America. J. of Paleont.61, p.595-603.
Species: Baiotomeus douglassi (Simpson, 1935) Hartman, 1986(?)
Aka: Mimetodon douglassi Jepsen, 1940; Neoplagiaulax douglassi Schiebout, 1974; Ptilodus douglassi Simpson, 1935d
Place: Gidley Quarry, Montana & Wyoming
Country: USA
Age: Torrejonian, Paleocene
Remarks: A fairly substantial multi of near 200g. How this could possibly have been referred to Baiotomeus in 1986 is something I don't understand. Krause formally established the genus in 1987. Life's full of mysteries.
Reference: Simpson (1935), New Paleocene mammals from the Fort Union of Montana. Proc. US Nation. Museum 83, p.221-244.
Species: Baiotomeus lamberti Krause DW, 1987
Aka: cf. Mimetodon sp.; Ptilodus montanus?
Place: Medicine Rocks, Tongue River Formation, Montana
Country: USA
Age: Paleocene
Remarks: Several specimens, including the holotype, are at the Peabody Museum, Yale. Collected in 1958 and 1965, these were originally described as belonging to Mimetodon.
Reference: Krause (1987), Baiotomeus, a new ptilodontid multituberculate (Mammalia) from the Middle Paleocene of western North America. J. of Paleont.61, p.595-603.
Species: Baiotomeus russelli Scott CR, Fox RC & Youzwyshyn GP, 2002
Place: Cochrane 2, Paskapoo Formation, Alberta
Country: Canada
Age: lower Tiffanian, Paleocene
Remarks: The following is based on my reading of Scott et al 2002.
Remains consist of nine upper premolars, (P4), which average out to nearly 2,5mm in length. They're smaller than the teeth of other genus members; in terms of anteroposterior length approximately 45% less than B. douglassi and 40% below B. lamberti. The rows of cusps also display a strong curvature and the "cuspate anterolabial lobe" is better developed, (whatever it might be). Oh, and there's 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. Anyway: "The enamel is weakly wrinkled on all specimens ", (p.695).
The authors add: "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 Russell LS: "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 it's part of the Paskapoo, as originally concluded by Russell LS in 1929.
Reference: Scott CR, Fox RC & Youzwyshyn GP (2002), New earliest Tiffanian (late Paleocene) mammals from Cochrane 2, southwestern Alberta, Canada. Acta Palaeontologica Polonica 47 (4), p.691-704.
Page references: Kielan-Jaworowska Z & Hurum JH (2001), Phylogeny and Systematics of multituberculate mammals. Paleontology 44, p.389-429.
Scott CR, Fox RC & Youzwyshyn GP (2002), New earliest Tiffanian (late Paleocene) mammals from Cochrane 2, southwestern Alberta, Canada. Acta Palaeontologica Polonica 47 (4), p.691-704.
(This information has been derived from [1] MESOZOIC MAMMALS; Ptilodontoidea, an internet directory. As that's my webpage, there are no issues of copyright. Trevor Dykes)