Dire wolf, Canis dirus of east-central Sonora, Mexico

We describe the first occurrence of the extinct dire wolf, Canis dirus, from the late Pleistocene deposits of east central Sonora, Mexico. Remains include a partially complete left mandible and a left distal fragment of humerus collected from the deposits at Terapa. Local environments are interpreted to have been a tropical marsh with thorn-scrub to deciduous forest including some component of a nearby grassland. Although the mandible is nearer to the size of other large species of Canis known to occur in Mexico, the deep and robust mandible, presence of an accessory cuspid on the p2, an enlarged and robust p4, and accessory cuspids on the posterior margin of the trigonid ally the Canis from Terapa with C. dirus. Length of p4 suggests a possible closer affiliation to C. d. guildayi than to C. d. dirus.