The microanatomy of the testes and testicular ducts (rete testis, ductuli efferentes, ductus epididymis and ductus deferens) of Leiolepis ocellata (Agamidae) was investigated using light microscopy including histochemistry. Each testis contains seminiferous tubules and interstitial tissues. The former house spermatogenic cells (spermatogonia A & B, preleptotene, primary and secondary spermatocytes, spermatids (steps 1–8) and spermatozoa) and Sertoli cells, while the latter comprise peritubular and intersitial tissues. The rete testis is an anastomosing duct, having intratesticular and extratesticular portions. The proximal region of ductuli efferentes has wider outer ductal and luminal diameters than those of the distal region. The convoluted ductus epididymis is subdivided into four regions (initial segment, caput, corpus and cauda), based on the ductal diameter, epithelium characteristics and cell components. The ductus deferens has the greatest diameter and is divided into the ductal and ampulla ductus deferens. The ductal portion is subdivided into the proximal and distal regions, based on the epithelium types and ductal diameters. The ampulla ductus deferens is a fibromuscular tube, having numerous mucosal folds projecting into the lumen. Spermiophagy is detectable in the ductus epididymis and ductus deferens. The present results contribute to improved fundamental knowledge on the microanatomy of the reptilian reproductive system.

Pewhom, A., Chumnanpuen, P., Muikham, I., Chatchavalvanich, K. and Srakaew, N. 2015. Microscopic structures of the ovary and female genital ducts of Supachai's caecilian, Ichthyophis supachaii Taylor, 1960 (Amphibia: Gymnophiona). -Acta Zoologica (Stockholm) 00: 000-000.The structures of the female reproductive system (ovary, oviduct and cloaca) of Ichthyophis supachaii were investigated by dissection, histology and light microscopy. Paired, elongated, sac-like ovaries are parallel to the gut and fat bodies. Follicle stages include germinal nests of oogonia and primary oocytes, early and late previtellogenic follicles, early and late vitellogenic follicles and atretic follicles. Germinal nests of oogonia comprise oogonia and prefollicular cells. Nests of primary oocytes contain clusters of synchronously developing primary oocytes enclosed by connective tissue. Primary oocytes are associated with follicular cells. Previtellogenic follicles initially form the vitelline envelope, theca cell layers and patches of ooplasmic glycoproteins. Vitellogenic follicles contain heterogeneously sized spherical yolk granules. Atresia is present in several stages of developing follicles. The oviduct is divided into the anterior, middle and posterior parts. All oviductal parts are lined by non-ciliated epithelium. A small number of mucous cells are present in the middle part. The cloaca of female I. supachaii is divided into the anterior and posterior chambers. The anterior chamber is lined by glandular stratified columnar epithelium, while the posterior chamber has stratified cuboidal epithelium with less mucus production. Our results contribute to useful information on the reproductive biology of caecilians.

We investigated the structure of the male reproductive system in Ichthyophis supachaii. The testis comprises a series of mulberry-like lobes, each of which contains testis lobules occupied by germ cysts. A single cyst consists of synchronously developing germ cells. Six spermatogenic cell types, viz. primary spermatogonia, secondary spermatogonia, primary spermatocytes, secondary spermatocytes, spermatids and spermatozoa, have been identified and described. Notably, the testis of I. supachaii encompasses specific organization patterns of spermatids and spermatozoa during spermiogenesis. Spermiating cysts rupture and release spermatozoa to the collecting ducts, which are subsequently transported to the sperm duct, Wolffian duct and cloaca. We report for the first time ciliated cells in the epithelium of the caecilian Wolffian duct. The cloaca is divided into the urodeum and phallodeum. The urodeum has ciliated and glandular epithelia at its dorsolateral and ventral regions, respectively, as the lining of its internal surface. The muscular phallodeum is lined by ciliated epithelium. Paired Mullerian ducts lie parallel to the intestine and join the cloaca. The posterior portion of the duct is modified as the Mullerian gland. The most posterior region is non-glandular and lined by ciliated epithelium. Our findings contribute further to information on the reproductive biology of caecilians in Thailand.

Background Fundamental knowledge on the seasonal reproductive microanatomy and endocrinology of reptiles has been collected from several studies of various species. The present study was to determine annual changes in hormonal profiles, and detailed histomorphometric and histochemical characteristics of the entire male reproductive system of the tropical agamid lizard, Leiolepis ocellata. Results Male L. ocellata individuals (n = 75) collected from the territory of two provinces (Lampang and Tak) in northern Thailand exhibited annual variation in sex hormonal, histomorphometric, and histochemical characteristics of the male reproductive system. The reproductive cycle was subdivided into eight reproductive periods (early first active, first active, resting, second recrudescent, second active, regressive, quiescent, and first recrudescent), thus displaying a bimodal pattern with two actively reproductive periods. Circulating sex hormones (testosterone, estradiol, and progesterone) peaked in the first active (February) and the second active (June–July) periods. Likewise, gonadosomatic index (GSI) and histomorphometric variables of the testes and of the genital ducts (rete testis, ductuli efferentes, ductus epididymis, and ductus deferens) revealed their highest values in the first active period. Marked increase in protein and carbohydrate production was detectable in the ductuli efferentes during the active periods. Conclusions The male reproductive cycle of L. ocellata showed a biannual pattern of the hormonal profile, and detailed histomorphometric and histochemical characteristics of the entire reproductive system. Hence, the present study provides improved basic knowledge on the reptilian reproductive biology with comparative viewpoints to other reptiles.