Long-legged pursuit carnivorans (Amphicyonidae, Daphoeninae) from the early Miocene of North America. (Bulletin of the American Museum of Natural History, no. 318)

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dc.contributor.author Hunt, Robert M., Jr.
dc.date.accessioned 2009-03-23T13:02:22Z
dc.date.available 2009-03-23T13:02:22Z
dc.date.issued 2009
dc.identifier.uri http://hdl.handle.net/2246/5948
dc.description 95 p. : ill. (1 col.), map ; 26 cm. Includes bibliographical references (p. 84-87). en
dc.description.abstract In the early Miocene, endemic North American amphicyonids of the subfamily Daphoeninae evolved a lineage of large beardogs adapted for prey pursuit over open terrain. Three species comprise this lineage, here placed in the genus Daphoenodon, subgenus Borocyon Peterson, 1910, the sister subgenus to the daphoenine beardog Daphoenodon (Daphoenodon). These species (Borocyon robustum, B. niobrarensis, B. neomexicanus, n. sp.) are distinguished by limbs modified for fore-aft motion and parasagittal alignment contributing to a lengthened stride. These adaptive features are most evident in the terminal species, B. robustum, where the forelimb is conspicuously elongated. The species of Borocyon increase in body size from small B. neomexicanus, known only from the latest Arikareean of northern New Mexico, through earliest Hemingfordian B. niobrarensis from western Nebraska and southeast Wyoming, to B. robustum, likely the keystone predator of its guild. Borocyon robustum (~ 100-150 kg) was the most widely distributed, occurring during the early Hemingfordian from the Pacific Northwest through the Great Plains to the Florida Gulf Coast. Regional aridity prevalent in the North American midcontinent during the Arikareean may have contributed to the emergence of Borocyon by providing an appropriate niche for a long-legged, open-country predator. The skeleton of Borocyon robustum, based on composite elements acquired over many decades, reveals a carnivoran unlike any living pursuit predator. The species displays a mosaic of postcranial features that parallel limb elements of both highly evolved cursors (Canis lupus, Acinonyx jubatus) and large, ambush felids (Panthera leo, P. tigris). Skeletal traits contributing to its efficient locomotion include: proportionately lengthened forelimbs, the parasagittal radioulnar articulation with the humerus, an elongate radius and ulna, a modified carpal structure, and paraxonic elongate metapodials of the fore- and hindfoot, as well as details of the anatomy of femur, tibia, and proximal tarsals. These postcranial features indicate a large digitigrade predator with a number of anatomical parallels in the forelimb to running pursuit predators such as the wolf, but there are also musculoskeletal adaptations of the shoulder and hindlimb that compare with those of large, living felids. Skull, dentition, and mandibular anatomy are similar to those of living wolves. However, Borocyon robustum, on average a much larger carnivore, placed even greater emphasis on a pattern of dental occlusion and toothwear suggesting both carnivory and durophagous habits. Physiological attributes of Borocyon that may have contributed significantly to its adaptive program as a pursuit predator remain unknown. en
dc.format.extent 20732478 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US en
dc.relation.ispartofseries Bulletin of the American Museum of Natural History, no. 318. en
dc.subject Borocyon. en
dc.subject Miocene. en
dc.subject Fossils. en
dc.subject Forelimb. en
dc.subject North America. en
dc.title Long-legged pursuit carnivorans (Amphicyonidae, Daphoeninae) from the early Miocene of North America. (Bulletin of the American Museum of Natural History, no. 318) en
dc.title.alternative Neogene amphicyonid Borocyon. en

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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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