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Basicranial morphology and relationships of Antillean Heptaxodontidae (Rodentia, Ctenohystrica, Caviomorpha). (Bulletin of the American Museum of Natural History, no. 363)

Show simple item record MacPhee, R. D. E. 2012-01-04T13:47:26Z 2012-01-04T13:47:26Z 2011-12-30
dc.description 70 p. : ill. (some col.) ; 26 cm. en_US
dc.description.abstract What, if much of anything, are "Antillean heptaxodontids"? Over the course of nearly a century and a half, these caviomorph rodents, with their distinctive quasilamellar cheek teeth and generally large body size, have been diversely regarded as members of Chinchilloidea, or Cavioidea, or Octodontoidea; as distinct enough to warrant their own family or subfamily, or as no more than an offshoot within Dinomyidae or Capromyidae; and as having diverged from other caviomorph clades as early as the Oligocene, or as recently as the late Neogene. Similar uncertainties concern the taxonomic content of the group. It has been repeatedly suggested that the Antillean Heptaxodontidae as usually organized may be paraphyletic, but no adequate character-based arguments have appeared that might form a strong basis for reassessment. This paper attempts to arrive at some serviceable solutions to the heptaxodontid problem by utilizing the character-rich domain of the auditory region. Thus Amblyrhiza inundata (St. Martin/Anguilla) and Elasmodontomys obliquus (Puerto Rico), the chief subjects of this contribution, have traditionally been regarded as closely related on the basis of dental features. Yet certain basicranial characters, analyzed here for the first time, reveal that Amblyrhiza possesses derived features of bullar development and middle-ear vascularization that are found in this specific combination only in Chinchilloidea. These features are also seen in the Mio-Pliocene Patagonian taxon Eumegamys, reinforcing the position that it belongs in this grouping as well. The basicranial morphology of Elasmodontomys is rather primitive, and where it should be placed cladistically remains indeterminate, although its likeliest position is within Octodontoidea. Although it is taken for granted that no single set of morphological features will satisfactorily capture relationships throughout a large group like Caviomorpha, the absence of basicranial characters in most morphology-based systematic discussions of these rodents is glaring. The results reported here, while suggestive in their own right, should now be tested against much larger datasets. en_US
dc.language.iso en_US en_US
dc.publisher American Museum of Natural History. en_US
dc.relation.ispartofseries Bulletin of the American Museum of Natural History, no. 363. en_US
dc.subject Amblyrhiza inundata. en_US
dc.subject Elasmodontomys obliquus. en_US
dc.subject Heptaxodontidae. en_US
dc.subject Rodents. en_US
dc.subject West Indies. en_US
dc.title Basicranial morphology and relationships of Antillean Heptaxodontidae (Rodentia, Ctenohystrica, Caviomorpha). (Bulletin of the American Museum of Natural History, no. 363) en_US
dc.title.alternative Heptaxodontid basicrania and relationships. en_US

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  • Bulletin of the American Museum of Natural History
    The Bulletin, published continuously since 1881, consists of longer monographic volumes in the field of natural sciences relating to zoology, paleontology, and geology. Current numbers are published at irregular intervals. The Bulletin was originally a place to publish short papers, while longer works appeared in the Memoirs. However, in the 1920s, the Memoirs ceased and the Bulletin series began publishing longer papers. A new series, the Novitates , published short papers describing new forms.

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