Conspecificity of two pocket mice, Perognathus goldmani and P. artus

"Conspecificity of two pocket mice, Perognathus goldmani and P. artus" by E. Raymond Hall and Marilyn Bailey Ogilvie is a study of two types of pocket mice that looks at how they might be related. The study, made in the late 1950's, looks at the shapes and sizes of these mice and where they live to understand how they fit into their species group, especially where the two types mix in Mexico. Scientists looked closely at the mice from different places, took careful measurements, and noticed they were different sizes and had different skull shapes. Because the two types seemed to blend together in some areas, the scientists came to believe that one type of mouse should actually be considered a subtype of the other, and suggest more research should be done on similar animals.