The cranial osteology of Spermophilus richardsonii [Sabine, 1822] [Richardsons ground squirrel] [Mammalia: Rodentia: Sciuridae]

Much is known of the ecology and behaviour of Spermophilus richardsonii (Sabine, 1822) (Richardson's Ground Squirrel), but little has been discussed of its anatomy. Here we document details of its cranial anatomy, based upon 95 specimens from a single locality, focusing primarily on previously undescribed features. This documentation provides the essential information for studying intra- and interpopulational variation in cranial characteristics in both quantitative and qualitative contexts. Skulls of S. richardsonii examined were generally uniform in structure, and no obvious sexual differences were observed.