Comparative sperm ultrastructure of two tegu lizards (genus Salvator) and its relation to sperm competition

Abstract

The knowledge of sperm ultrastructure of Squamata provides informative traits for phylogenetic analyses. Furthermore, several sperm ultrastructure traits are important for sperm motility and longevity. Here, we provided a detailed ultrastructural description of the spermatozoa of two closely related teiid lizards, Salvator rufescens and S. merianae. We carried out an interspecific comparison of sperm ultrastructure traits and discussed their possible relation to sperm competition risk. Sperm ultrastructure of the two species shared patterns with other lizards previously described. The lack of interspecific differences in most sperm subcellular components, suggested that sperm ultrastructure traits are conserved within the genus Salvator and thus pointed out an important phylogenetic influence. However, we detected interspecific differences in the number of mitochondria and dense bodies sets, suggesting differences in the amount of energy available for sperm motility and longevity. Further comparative studies are urgently needed to understand the sperm metabolic pathways in neotropical lizards in general.