Biosystematics of the Chewing Lice of Pocket Gophers

Abstract

One of the greatest challenges in systematic and evolutionary biology con­ cerns the taxonomy, coevolution, and biogeography of chewing lice of the genera Geomydoecus and Thomomydoecus (Mallophaga: Trichodectidae) and their vertebrate hosts, the more than 400 recognized species and subspecies of pocket gophers (Rodentia: Geomyidae). Pocket gophers are fossorial rodents restricted geographically to North and Central America. They are relatively sedentary, exhibit low vagility, and have male and female exclusive territo­ ries, low population densities, and patchy distributions. The tendency of groups of these mammals to occur in small local populations has resulted in the development of minor character differences that led to recognition of as many as 230 subspecies within a single species (14). In addition, researchers have long known that the relationships among many of these gopher taxa are poorly understood (1). Fortunately, pocket gophers are common enough to be well represented in major vertebrate collections and have been the subject of exhaustive morpho-