Morphology and histology of paryphasmata and hemibaculum of Varanus salvator based on sexual maturity

Abstract

Background: Varanus salvator is one of the reptiles being hunted by human beings for several purposes, including traditional medicine. The studies about reproductive biology aspects were limited.
Aim: This study aimed to determine the morphology, histology, and histometry of V. salvator paryphasmata and hemibaculum based on Snout-Vent Length (SVL) as an indicator of sexual maturity.
Methods: This study examined 18 pairs of hemipenis of V. salvator with SVL more and less than 40 cm in equal number. Paryphasmata and hemibaculum parts were observed visually and micro-sliced, then stained with Hematoxylin-Eosin (HE). The histological observation was conducted under a 40×, 100×, and 400× magnification of a light microscope. The histometry of the paryphasmata was examined using 13 Megapixels Coolpad and OptiLab Plus for microscopic pictures. The chondrocyte cell area was measured using the Optilab Plus and Image Raster three applications.
Results: The sizes of glans of hemipenis, paryphasmata, and hemibaculum increased according to the increasing of SVL. The average paryphasmata row number, epidermis, and loose connective tissue thickness were not significantly different (p > 0.05). However, dense connective tissue was thicker (p < 0.05), which corresponds to SVL. Hemibaculum was composed of fibrous and hyaline cartilage characterized by chondrocyte cells. The SVL also affects (p < 0.05) the ossification of hyaline in hemipenis, while the chondrocyte cell area followed the equation −1.87E7 + 7.09E5* SVL.
Conclusion: The SVL size of V. salvator affects the paryphasmata, hemibaculum, thickness of dense connective tissue of paryphasmata, and the area of chondrocyte cells.