Distal Urogenital Anatomy of Male Prairie Racerunners, Aspidoscelis sexlineatus viridis (Reptilia: Sauria: Teiidae)

I examined histologically the distal urogenital anatomy in male Prairie Racerunners ( Aspidoscelis sexlineatus viridis ) from a small seasonal sample of individuals collected in Arkansas in order to provide additional information regarding squamate urogenital anatomy. Specifically, I focused on the basic anatomy and positioning of posterior ducts and associated structures in this teiid lizard. The anatomical structures included the ductus deferens, ampulla ductus deferens, ampulla urogenital papilla (Aup), ureter, inner core tissue mass, urodaeum, and the urogenital papilla. The two Aup, which are small complimentary blind pouches representing the terminal repositories for products released by urogenital ducts, are striking anatomical features of the distal urogenital anatomy in this lizard. Interestingly, the Aup, which are characteristic anatomical structures present in very few additional lizard species (e.g., in some members of families