Hipparionin material recovered from the middle Miocene El Camarón Formation (late early Barstovian, K-Ar dated 15. 0 ± 0.8 to 16.7 ± 0.71 Ma) of the state of Oaxaca, southeastern Mexico, is formally described. The sample consists of upper and lower cheek teeth, whose sizes and occlusal patterns are closest to those of the North American Cormohipparion quinni from the late Barstovian of the Great Plains. The material is referred to C. aff. C. quinni and constitutes one of the southernmost occurrences of the genus, extending its geographic distribution from the Northern Great Plains to southeastern Mexico during the middle Miocene. The dentally derived species reported here is contem poraneous with C. goorisi from the early Barstovian of Texas and Florida, the oldest and most plesiomorphic known species, thus lending support to the hypothesis that part of the hipparionin differentiation probably took place in southern (tropical) North America. This in turn leads to a reappraisal of where and when the radiation of some middle Miocene hypsodont horses actually occurred.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.