A thorny question: the taxonomic identity of the Pirro Nord vertebrae

The past geographic distribution of the genus Theropithecus (Primates: Cercopithecidae) is mainly restricted to Africa. Outside that continent, the earliest reported records of this genus consist of a calcaneus of cf. Theropithecus sp. from ‘Ubeidiya (Israel, 1.6e1.2 Ma [millions of years ago]), as well as three associated cervical vertebrae from Pirro Nord (Italy, 1.7e1.3 Ma) attributed to Theropithecus sp. The attribution of the Pirro Nord vertebrae to this genus has been disputed on morphometric grounds, although their assignment to a large-bodied cercopithecid has remained undisputed. Here we report unpublished cervical vertebral specimens with a similar morphology and, given their significance for the paleobiogeography of Theropithecus (purportedly representing its earliest European record), we reevaluate their taxonomic attribution. In particular, we reconsider the possibility that they belong to another non-primate mammal recorded at this site. Based on both qualitative and metric morphological comparisons, we strongly favor an alternative attribution of the cervical vertebrae from Pirro Nord to the large porcupine Hystrix refossa, which is widely documented at the site by both dentognathic and other postcranial remains. We therefore conclude that the dispersal of Theropithecus out of Africa before ca. 1 Ma (when it is recorded by dental remains from Cueva Victoria, Spain) is currently based only on the calcaneus from ‘Ubeidiya tentatively attributed to this genus.