Phallus Development in the Caiman latirostris. Preliminary Results

LAURA BERÓN; MARIA VIRGINIA PARACHÚ MARCÓ; NOELIA VILLAFAÑE; JOSEFINA LUCIANA IUNGMAN

Skukuza

Congreso; 24th Crocodile Working Meeting; 2016

Crocodile Specialist Group of the Species Survival Commision of the UICN

In this study we provide a morphological description of Caiman latirostris phallus during their early ontogenesis. Caiman eggs were incubated at 33°C (male producing temperature), and samples were obtained at stages 24 and 26 (after the thermo-sensitive period) of embryonic development, at hatching time (or stage 28), and 24 months after hatching (juvenile). During the periods mentioned above, the phallus had an oval shape with a ventral and dorsal surface and two lateral edges; and a phallic sulcus running along its dorsal surface. In the gross anatomy two segments were recognized: the shaft and the glans (distal expansion like cuff). At stage 24, the sulcus was a stratified epithelium, flanked by irregular shaped cells and a profuse fundamental substance. Between stages 26 and 28, a ring of vascular elements distinguished the anlage of the corpora cavernosa from the corpus spongiosum; this latter immediately bordering the phallic sulcus. The corpora exhibited a network of collagen fibers loosely organized. Smooth muscle cells were differentiated adjacent to the phallic sulcus on the dorsal surface of the corpus spongiosum. Nerves were developing accompanying the anlage corpora organization. By juvenile period, the sulcus in the deep lumen was stratified ciliated epithelium with mucin cells different from earlier stages. The corpora cavernosa had turned into corpora fibrosa with smooth muscle bundles mixed among rich tissue collagen fibers. The muscle bundles in the corpora cavernosa had formed two orientations, radially (deeply) and longitudinally (superficial)-orientated, while in the corpus spongiosum the muscle was longitudinally-orientated aligned with the sulcus. The glans contained a lacunar connective tissue, with large and irregular vascular spaces. Our analysis of caiman phallus development after the thermo-sensitive period, suggests that the glans development and the epithelium sulcus specializations are post-hatching process.