Sex identification in Australian skinks (Egernia stokesii, E. hosmeri, E. striolata) using cloacoscopy

Abstract

Thirteen adult healthy captive skinks, six Gidgee spiny-tailed skinks (Egernia stokesii), three Hosmer's spiny-tailed skinks (Egernia hosmeri) and four tree crevice-skinks (Egernia striolata), were submitted to the study. The weight of the animals ranged from 28 g to 146 g. All skinks were explored during their putative mating season, which is December. Lizards were restrained manually and positioned in ventral recumbence. Cloacoscopy was performed with the rigid endoscope, protecting channel, endocamera and recording system Telepack-Pal (Karl Storz Endoskope, Tuttlingen, Germany). While the endoscope was gently introduced into the cloaca and advanced into the coprodeum sterile saline was flushed into the cloaca through the protecting channel. The endoscope was then slowly withdrawn to allow visualization of the main structures of the urodeum and proctodeum. Male skinks are characterized by the presence of urethral papillae and only one horizontal septum which divides the chamber of the urodeum into two subchambers. Female skinks are characterised by the presence of two septa. The central-dorsal fold that divides the urodeum into two pouches in female skinks is absent in males. Cloacoscopy proved an effective method of sex identification and can be considered a valuable method for breeding and conservation in monomorphic skink lizards.

Keywords

• lizard cloaca
• monomorphic reptiles
• urodeum
• vaginal pouch