The Anatomy and Taxonomic Significance of the Male Accessory Reproductive Glands of Muroid Rodents

Abstract

The structures of the male reprodudtive tracts of 24 genera of muroid rodents were compared to assay characters of potential taxonomic utility. One form, Sigmodon hispidus, was studied in detail to serve as a basis for comparison. Analysis of the accessory reproductive gland complement in 24 genera of murid, cricetine, and microtine rodents reveals that these structures vary in both number and form. The bulbo-urethral glands are the least variable elements while the preputial, ampullary, vesicular, and prostate glands show considerable modifications. The prostates, though variable in form and occasionally lacking one or more of the three usual pairs of glandular material, are never totally absent. The vesicular, ampullary, and preputial glands are lost singly or in various combinations in 8 of 22 genera for which such information is available. The accessory reproductive glands show greater similarity between certain genera currently placed in separate families than between some genera classified within the same family. Certain cricetines, such as Oryzomys and Sigmodon, have reproductive tracts of a basic pattern shared by both murids and microtines; other cricetines including Peromyscus, Neotoma, Onychomys, and Tylomys, differ radically from this basic pattern. This indicates a polyphyletic origin of the Cricetidae and suggests that genera currently classified as cricetines should be assigned to different taxa.