Oxyrhopus in Bahia, Brazil: Pholidosis, Maturity, Sexual Dimorphism, and Reproduction

Abstract

Research on snake reproduction in the Neotropics is limited by a lack of data, necessitating further studies to better understand their reproductive biology. The genus Oxyrhopus, has received increasing interest in studying its natural history, although several aspects remain unknown. This investigation aims to shed light on its morphometry, maturity, and sexual dimorphism in the state of Bahia, Brazil. An analysis was conducted on 421 snake specimens from the Museum of Zoology at the State University of Santa Cruz to determine their external characteristics and reproductive conditions through gonadal inspection. Species identification was performed via pholidosis, and various measurements such as snout-vent length, tail length, head length, and width were meticulously recorded. Sexual maturity was estimated, and sexual dimorphism was assessed through statistical analysis, including regressions and seasonal comparisons, to study reproductive cycles and testicular variations in these species. The species of the genus Oxyrhopus studied included O. trigeminus, O. petolarius, O. guibei, and O. rhombifer. The investigation delineated the minimum size required for sexual maturity in each species and clarified the disparities in body size between males and females. Reproductive males were found throughout the year in O. trigeminus and O. petolarius, with no significant seasonal differences in testicular volume. Females of both species exhibited annual reproductive activity. Similar patterns were observed in O. guibei and O. rhombifer, albeit with fewer data available. A relationship between female body size and fecundity was found, but further research is needed on how climatic factors may influence the reproductive cycle.