Baluchimyinae, a new ctenodactyloid rodent subfamily from the Miocene of Baluchistan. American Museum novitates ; no. 2841

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New York, N.Y. : American Museum of Natural History
"Rodents from early Miocene deposits near Dera Bugti, Baluchistan, Pakistan, represent an endemic radiation of ctenodactyloids in the Indian subcontinent. The Bugti small mammal fauna contrasts sharply with other known middle Cenozoic faunas, but most taxa can be referred to the Chapattimyidae, a family known previously from Eocene deposits of the Indian subcontinent. Four new genera, Baluchimys, Lindsaya, Lophibaluchia, and Hodsahibia are placed in the new subfamily Baluchimyinae. The Baluchimyinae and the new genus Fallomus are placed in the redefined Chapattimyidae. An additional, rare element in the Bugti fauna, Downsimys margolisi new genus and species, is named without referral to family, but affinities may lie with chapattimyids or cylindrodontids. A single large tooth resembles specimens from Qujing, Yunnan, China, that are referred to the yuomyid Dianomys. The Bugti fauna must be considered in formulating hypotheses of relationships of higher rodent taxa and in biogeographic reconstructions. The fauna indicates that the Chapattimyidae are a diverse South Asian clade that is closely related to the northern Yuomyidae and Ctenodactylidae. All three families are classified in the superfamily Ctenodactyloidea and are derived in their hystricomorphy with respect to the early Asiatic rodent Cocomys. Some evidence supports relationship of Baluchimyinae with African Thryonomyoidea. Evolution of Chapattimyidae and other ctenodactyloids is characterized by vicariant events in which different groups radiated to the south and to the north of the Tethys/Himalayas. If Chapattimyidae are close to Thryonomyoidea, then this establishes a record of Eocene rodents in the northern hemisphere of the Old World that could lie near the origin of African hystricognaths on the one hand and South American Caviomorpha on the other. This scenario then implies monophyly of most African, Asian, and South American hystricomorphous rodents. However, unless baluchimyines or late Paleogene Asiatic relatives prove to have hystricognathous jaws, this interpretation requires that hystricognathy arose independently in Oligocene African and South American groups"--P. 2.
58 p. : ill., maps ; 26 cm.
Includes bibliographical references (p. 53-58).