We describe the relatively complete skeleton of Tetraclaenodon undoubtedly associated with its dentition, from the Torrejonian interval of the Nacimiento Formation in the San Juan Basin, New Mexico. Tetraclaenodon is the most primitive and oldest genus of the family Phenacodontidae and is very important for assessing the phylogenetic relationships of the family. The newly described skeleton belonged to a lightly built terrestrial mammal that could use trees for shelter. The structure of the ulna, manus, femur, crus, and pes corresponds to that of a typical terrestrial mammal, while morphological features such as the low greater tubercle of the humerus, long deltopectoral crest, pronounced lateral supracondylar crest, and hemispherical capitulum indicate some scansorial adaptations of Tetraclaenodon. The postcranial skeleton of Tetraclaenodon does not exhibit the cursorial adaptations seen in later phenacodontids and early perissodactyls. Phylogenetic analysis did not recover monophyletic “Phenacodontidae”; instead, phenacodontids formed a series of sister taxa to the Altungulata clade. Tetraclaenodon is the basal-most member of the “Phenacodontidae” Altungulata clade.
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.
Vol. 86 • No. 1