Testicular cycle of amphisbaena mertensii strauch, 1881 (squamata: amphisbaenidae) in northeastern Argentina

Abstract

The perpetuation of species depends mainly on their reproductive success, thereby the study of reproductive biology is an important matter for understanding the evolution of life-history strategies (Seigel and Ford, 1987; Holycross and Goldberg, 2001). Knowledge of amphisbaenian reproduction is scarce and fragmentary because the diggers and fossorial habits of worm lizards decrease the probability of encounter in nature (Andrade et al., 2006). Reproductive data are available for only 12% out of 197 species (Andrade et al., 2006; Uetz and Hošek, 2017). Published information consists of clutch and eggs sizes, oviposition season, and changes in gonadal sizes (Andrade et al., 2006). The testicular cycles known are based in the external morphology of the vas deferens and variation of testes weight and size (Andrade et al., 2006). The use of histological and hormonal techniques allows to determine more precisely the minimum size at sexual maturity using a small sample, and the timing of the gametogenesis and its correlation with macroscopic variation of the gonads (Boretto and Ibargüengoytía, 2009; Boretto et al., 2012). In amphisbaenians, histological studies related to the reproductive activity of males and females are restricted to Blanus cinereus Vandelli, 1797 (Blanidae) and Trogonophis wiegmanni Kaup, 1930 (Trogonophiidae) of Morocco (Bons and Saint-Girons, 1963) and Diplometopon zarudnyi Nikolsky, 1907 (Trogonophiidae) of Saudi Arabia (Al-Dokhi et al., 2013; Al-Sadoon et al., 2014).