The Hemipenes of Some Snakes of the Semifossorial Genus Atractus, with Comments on Variation in the Genus

Abstract

The hemipenes of seven species of Atractus (Atractus emigdioi, Atractus major, Atractus mariselae, Atractus poeppigi, Atractus torquatus, Atractus univittatus, and Atractus ventrimaculatus) are described. Hemipenial morphology in this poorly known genus of snakes is found to be particularly variable among the species studied. Additionally, the primitive unicapitate hemipenal condition is more widespread among Atractus than was previously thought. Given the drastic variation in hemipenal morphology observed in Atractus, it is likely that characters derived from studying this organ may prove especially useful for future work on intrageneric relationships among members of this genus.