Cloacal microanatomy of tropical male butterfly lizards (genus Leiolepis) during the annual reproductive cycle

Cloacal microanatomy of male Leiolepis ocellata during the reproductive cycle was examined using histochemistry and light microscopy. The cloaca is divided into three contiguous regions: the coprodeum, urodeum, and proctodeum. The coprodeum has anterior and posterior connections to the intestine and the urodeum, respectively. A bladder stalk and paired ampulla ureters open to the ventral and the dorsal urodeal walls, respectively. Paired, bilateral anterior dorsal recesses of the urodeum lie ventrally to ureters and ampulla ductus deferentes. A cloacal triad junction is indicated by confluence of the coprodeum, urodeum, and bladder stalk. The proctodeum is subdivided into the anterior and the posterior regions; the latter bears dorsal and ventral proctodeal glands. In general, similar histological profiles of each cloacal region are noticeable among animals from different reproductive periods. However, mucosal glycoconjugate production in the cloacae of reproductively inactive males is slightly less than that in the active males. Seasonal histological changes of proctodeal glands are appreciable, with the reproductively active males having structurally and functionally active glands. As expected, spermatozoa are found in the urodeal and the proctodeal lumina of the active males, while residual round germ cells are occasionally found in the cloacae of the inactive males. Overall, male L. ocellata exhibits seasonal cyclicity of microanatomy and histochemistry of the proctodeal glands, with marginal histological variability in other parts of the cloacae. Hence, the present study provides improved knowledge on dynamic microanatomical variation of the male reproductive system of reptiles in relation to the annual reproductive cycle.