PaleoBios

A lower jaw from the White Cone local fauna of the latest Hemphillian Bidahochi Formation in northern Arizona is the first description of a felid from this fauna and the first positively identified occurrence of the smilodontine machairodont Paramachairodus in North America. This lower jaw has characters identical to those seen in a similar sized machairodont felid from the Bone Valley Formation of Florida, suggesting that the same taxon is present in Florida. The diversity of the Hemphillian machairodonts and the taxonomic status of Megantereon hesperus is reviewed. The characteristics of the ramus corpus and dentition places Paramachairodus firmly within the Smilodontini and adds further support that the more derived smilodontine machairodonts, Megantereon and Smilodon, had their origins in North America.