Anatomy and Histology of the Male Reproductive Tract and Spermatogenesis Fine Structure in the Lesser Anteater (Tamandua tetradactyla, Myrmecophagidae, Xenarthra): Morphological Evidences of Reproductive Functions

Abstract

The anatomy and histology of the male genital tract of the lesser anteater were studied. Fine details of spermatozoa regarding their genesis and morphology were also studied in six adult specimens. The testes lie in the pelvic cavity. The deferent duct emerges from the epididymis and opens into the ejaculatory duct, which drains into the membranous urethra. Accessory glands (prostate, seminal vesicle and bulbourethral gland) are histologically similar to those described in other mammals. The short penis presents an urethral orifice, while the corpus spongiosum becomes thinner at the end indicating the absence of a histologically defined glans. The seminiferous epithelium shows: (1) Sertoli cells with deep nuclear indentations, (2) spermatogonia with crusty-like chromatin, (3) spermatocytes at different stages of maturation and (4) three morphologically distinct stages of spermatid differentiation according to nuclear shape, acrosome development and chromatin condensation. Sperm heads appear oval. The length of the spermatozoa averages 67.33 ± 1.60 μm. Two specimens with inactive spermatogenesis were azoospermic. Their testes and epididymis presented sizes smaller than those with active spermatogenesis. These studies together with others in anteaters may contribute to successful breeding in conservation programmes.

Morphological and histological characters of penile organization in eleven species of molossid bats

“…Based on the predominance of erectile and/or connective tissue in the mammalian penis, Wrobel and Bergmann (2006) classified it into three types: vascular (prevalence of erectile tissues), fibroelastic (prevalence of fibroelastic tissues), and intermediate (without prevalence of one tissue over the other). Penises of the analyzed specimens are vascular, a condition that appears to dominate among mammalian species previously analyzed (Kamikawa-Miyado et al, 2005;Yiee and Baskin, 2010;Rossi et al, 2012).…”

Morfologi Hemipenis Biawak Air (Varanus salvator bivittatus)

“…Hemipenis yang disusun oleh corpus cavernous tanpa otot polos juga ditemukan pada kura-kura P. geoffroanus (Cabral et al, 2011) dan ular Bittis arietans arietans (Karim, 1998). Hal ini berbeda pada ular Crotalus durissus terrificus (Porto et al, 2013) dan penis mamalia (Goldstein and Padma-Nathan, 1990) pada umumnya seperti pada Tamandua tetradactyla (Rossi et al, 2012), Trenggiling (Manis javanica) (Akmal, 2014), dan muncak (Muntiacus muntjak muntjak) (Wahyuni, 2012), bahwa sebagian besar parenkim corpus cavernous terdiri atas bundel otot polos yang berelaksasi atau kontraksi saat kopulasi.…”

Morphology of the adrenal glands of giant anteater (Myrmecophaga tridactyla, Linnaeus, 1758) of wild life

“…They are members of Superorder Xenarthra belonging to family Pilosa (SANCHEZ et al, 2013), previously described as family Mymercophagidae (SHAW;MCDONALD, 1987;ROSSI et al, 2012). This family of mammals constitute an important conservation group, because is highly vulnerable, according to Brazilian Official List of Species Threatened with Extinction (CRUZ et al, 2013;IBAMA, 2016) and "near threatened" in Red List of the International Union for Conservation of Nature (ROSSI et al, 2012;CRUZ et al, 2013;IUCN, 2015) and since 2003 is included in the Appendix II of the Convention on International Trade in Endangered Species (SANCHES et al, 2013). Although in recent years, M. tridactyla is threatened with extinction, it had a much wider geographical distribution in past times, inhabiting even other sub-continents, such as North America according to the discovery of fossil records (SHAW;MCDONALD, 1987).…”