Comparative Morphology of the Two Species of Grasshopper Mice, Genus Onychomys, in New Mexico

Inasmuch as individual specimens of the cricetid genus Onychomys Baird are frequently difficult to identify to species even using the commonly used key characters, a total of 376 grasshopper mice was examined to determine how and to what extent the two species, O. leucogaster and O. torridus, differ from each other in New Mexico. To this end, 31 measurements (cranial, skeletal, and hair) and ratios were ascertained for each individual. The nearly 12,000 figures were summarized by constructing 161 modified Dice-Lerass diagrams