The order Didelphimorphia (opossums) consists of one family and 87 currently recognized species found only in the Western Hemisphere (Wilson and Reeder 2005). Only one species occurs north of Mexico in North America and that species’ range includes the state of Mississippi. Two key characters used to define (and in most cases distinguish) Didelphimorphia include pentadactyl (five-toed) feet and the primitive metatherian dental formula (5/4 incisors, 1/1 canines, 3/3 premolars, 4/4 molars = 50), adapted for omnivory. Didelphimorphia also possess a well-developed sagittal crest, long rostrum, and are polyprotodont (unshortened mandible, lower incisors small and specialized) and didactylous (unfused toes, each in their own skin sheath) (Feldhamer et. al. 2007).
Virginia opossum (Didelphis virginiana)