Comparative analysis of the sperm ultrastructure of three species of Phyllomedusa (Anura, Hylidae)

Abstract

AbstractWe describe the sperm ultrastructure of three species of frogs in the genus Phyllomedusa. According to micrographs, total size of the spermatozoon of Phyllomedusa hypochondrialis is significantly smaller than those of Phyllomedusa bicolor and Phyllomedusa tarsius. The acrosome complex consists of two conical structures covering the nucleus, the acrosome vesicle and the subacrosomal cone. The subacrosomal cone of P. bicolor and P. tarsius is less electron‐dense and appears more granular in transverse section than in P. hypochondrialis. In P. bicolor and P. tarsius, the nuclear space is reduced and the subacrosomal cone fills most of the space between the acrosome vesicle and nucleus. The anterior region of the nucleus in the spermatozoa of P. bicolor and P. tarsius ends abruptly, while in P. hypochondrialis it is sharp‐ended. In P. bicolor and P. tarsius, the axial fibre is much larger than in P. hypochondrialis. The sperm ultrastructure of Phyllomedusa appears conservative at the intrageneric level. Future studies on the sperm ultrastructure of hylids can provide new insights on the systematics of the group and a larger database for a cladistic analysis.