Panthera balamoides and other Pleistocene felids from the submerged caves of Tulum, Quintana Roo, Mexico

ABSTRACTHere we describe a new species of a Pleistocene felid based on the distal third of a right humerus from the submerged El Pit cenote (sinkhole) near Tulum in Quintana Roo, Mexico. The new taxon, Panthera balamoides sp. nov., is characterized by a large entepicondylar foramen, a gracile and straight humeral shaft with a prominent supracondylar ridge with a small depression on the lateral epicondyle and a distal articular surface located medially with respect to the long axis of the shaft.Two felid clavicles from the same locality have been assigned to Panthera atrox, while a humerus fragment from the Kim Ha cave near Tulum likely corresponds to Smilodon gracilis. Panthera balamoides lines up with other likely endemic mammals in the region, which suggest that at least northern Quintana Roo, if not the entire Yucatan peninsula, may have been ecologically isolated during the Pleistocene, due to the repeated expansion of grassland.