Thursday, 7 April 2016

A Haplocyonine Amphicyonid from the Early Miocene of Inner Mongolia.

Amphicyonids, or Beardogs, are an extinct group of Carnivoran Mammals known from the Eocene to Pleistocene of Europe, Asia, Africa and North America. Oppinions on their relationship to other Carnivorans vary, with some palaeontologists feeling they are more closely related to Dogs and others that they are more closely related to Bears. Amphicyonids were for the most part large animals, including the earliest specimens, and are interpreted as having had a hypercarnivorous diet (diet with a very high proportion of meat). The first Amphicyinids appear in the fossil record in Europe during the Eocene, with the group reaching North America during the Early Miocene,

In a paper published in the journal Vertebrata PalAsiatica on 30 March 2016, Wang Xiao-Ming of the Department of Vertebrate Paleontology at the Natural History Museum of Los Angeles County and the Key Laboratory of Vertebrate Evolution and Human Origins at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, Wang Hong-Jiang of the Administration Station of Cultural Relics of Xilinguole League and Jiangzou Qi-Gao of the Key Laboratory of Vertebrate Evolution and Human Origins at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences and the University of the Chinese Academy of Sciences, describe an isolated Amphicyonid tooth from the Early Miocene Aoerban Formation of Xilinhot League in Inner Mongolia.

The specimen is clearly an Amphicyonid, as the group have rather distinctive dentition. However it does not appear to be closely related to any previously described Asian Amphicyonid, with a morphometric analysis (a method used by palaeontologists that relies on comparing the ratios of different measurements to one-another rather than simply assigning the samples to groups based upon their obvious shape) placing it within the range of two groups, the North American Temnocyanines and the European Haplocyonines, and particularly close to Haplocyonoides mordax, a species known from the Miocene of Germany, France and Spain.

 Amphicyonid tooth from the Early Miocene of Inner Mongolia. Wang et al. (2016).
 
Temnocyanines are thought likely to have evolved from a Haplocyonine ancestor that reached North America, and the two groups are subsequently thought to have followed similar evolutionary trajectories, with both groups producing a similar range of forms. However the Aoerban Formation tooth dates from some time after the appearance of the earliest Temnocyanines in North America, and appears to resemble more advanced members of both groups, suggesting that it was not closely related to the earliest American members of the group, for which reason Wang et al. conclude that it was a Haplocyonine.

See also...

http://sciencythoughts.blogspot.co.uk/2015/11/possible-sexual-dimorphism-in-late.htmlPossible sexual dimorphism in a Late Miocene Red Panda.                          Pristinailurus bristoli is a Late Miocene Ailurid Mammal (a...
http://sciencythoughts.blogspot.co.uk/2015/01/two-new-species-of-carnivoraform.htmlTwo new species of Carnivoraform Mammals from the Middle Eocene of San Diego County, California.                                                The Order Carnivora includes the majority of modern carnivorous Mammals, including Dogs (Canids), Cats (Felids), Hyenas (Hyenids), Bears (Ursids)...
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