Morphological Variation of the Genus Peromyscus in Nebraska
The genus Peroreyscus is perhaps the most widely distributed of all the mammals of North America. Its range extends southward from Canada through the United States and Mexico into Central America and across the continent from the Atlantic to Pacific coast. Osgood1s (1909) revision of the classification of this genus has withstood the test of time. Despite the accumulation of new information, his view of the interrelationships among mice of this genus has served well. The current classification of Peromyacus (Hall and Kelson, 1959) is essentially that of Osgood. | Problems arise in identifying species and subspecies within the genus despite its seemingly solid taxonomic status. Hall and Kelson (1959) reason that the difficulty lies in the large number of species and the geographic variation within most species. Peromyscus does, indeed, encompass a large number of species. In 1964, Hooper and Musser suggested some modifications of the current classification to include 13 species-groups. Within these 13 groups, they named 59 species, most of which they admitted are morphologically very close to one another. To make matters more difficult, geographic variation within most of the species is marked. Thus the assignment of a specimen to a given species many times requires the efforts of an expert.
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