Discovery of a Male Phenotype of the Parthenogenetic Gecko, Lepidodactylus lugubris, on Ishigakijima Island of the Yaeyama Group, Ryukyu Archipelago

Abstract

We found one male phenotype of the parthenogenetic Lepidodactylus lugubris on Ishigakijima Island, Japan. This “male” had well developed hemipenes, preanal-femoral pores, and externally apparently normal testes. However, histological examination showed that spermatogenesis was aberrant in both testes and that mature spermatozoa were rare, if any, in the ductus epididymides. These facts strongly suggest the sterile nature of this individual. Because there are no bisexual species of Lepidodactylus on Ishigakijima and adjacent islands, the emergence of this “male” can not be explained on the ground of hybridization between a female L. lugubris and a male of a bisexual congener, or of the misidentification of a congener, as in cases of male emergences in a number of southern Pacific populations.