Ultrastructure of the reproductive system of the black swamp snake (Seminatrix pygaea). II. Annual oviducal cycle

Abstract

This article is the first ultrastructural study on the annual oviducal cycle in a snake. The ultrastructure of the oviduct was studied in 21 females of the viviparous natricine snake Seminatrix pygaea. Specimens were collected and sacrificed in March, May, June, July, and October from one locale in South Carolina during 1998 -1999. The sample included individuals: 1) in an inactive reproductive condition, 2) mated but prior to ovulation, and 3) from early and late periods of gravidity. The oviduct possesses four distinct regions from cranial to caudal: the anterior infundibulum, the posterior infundibulum containing sperm storage tubules (SSTs), the uterus, and the vagina. The epithelium is simple throughout the oviduct and invaginations of the lining form tubular glands in all regions except the anterior infundibulum and the posterior vagina. The tubular glands are not alveolar, as reported in some other snakes, and simply represent a continuation of the oviducal lining with no additional specializations. The anterior infundibulum and vagina show the least amount of variation in relation to season or reproductive condition. In these regions, the epithelium is irregular, varying from squamous to colum-nar, and cells with elongate cilia alternate with secretory cells. The secretory product of the infundibulum consists largely of lipids, whereas a glycoprotein predominates in the vagina; however, both products are found in these regions and elsewhere in the oviduct. In the SST area and the anterior vagina, tubular glands are compound as well as simple. The epithelium of the SST is most active after mating, and glycoprotein vacuoles and lipid droplets are equally abundant. When present, sperm form tangled masses in the oviducal lumen and glands of the SST area. The glands of the uterus are always simple. During sperm migration, a carrier matrix composed of sloughed epithelial cells, a glycoprotein colloid, lipids, and membranous structures surround sperm in the posterior uterus. During gravidity, tubular glands, cilia, and secretory products diminish with increasing development of the fetus, and numerous capillaries abut the basal lamina of the attenuated epithelial lining of the uterus.

Sperm storage and morphofunctional bases of the female reproductive tract of the snake Philodryas patagoniensis from southeastern Brazil

“…This characteristic provides an optimal arrangement of the space in the coelomic cavity during pregnancy (Perkins and Palmer 1996). The different oviductal regions described herein are also similar to other snakes regarding structure and function (Saint-Girons 1957;Bauman and Metter 1977;Mead et al 1981;Sever et al 2000;Siegel and Sever 2008a; . The epithelial cells secrete neutral carbohydrates and carboxylated glycosaminoglycans throughout the reproductive cycle (Gabe and Saint-Girons 1965;Uribe et al 1998;Sanchez-Martinez et al 2007;De Resende and Nascimento 2015).…”

“…However, the increase in neutral carbohydrate secretion in certain portions of the oviduct may be linked to sperm storage, as this reproductive tactic occurs in P. patagoniensis. This secretory activity has already been described for several snake species (Fox 1956;Saint-Girons 1975;Bauman and Metter 1977;Perkins and Palmer 1996;Sever et al 2000).…”

MORFOLOGIA DOS ÓRGÃOS GENITAIS FEMININOS DO MUÇUÃ (Kinosternon scorpioides)

“…Nas serpentes, SEVER et al (2000) descrevem o oviduto como formado por quatro partes, designadas infundíbulo anterior, infundíbulo posterior, útero e vagina.…”

“…O mesmo acontece com a salamandra, segundo GREVEN (1998), assim como nas aves, conforme GUPTA e MAITI (1987), HILDEBRAND (1995) e DYCE et al (1997, enquanto nas serpentes, segundo SEVER et al (2000), os ovidutos estão divididos em quatro partes: infundíbulo anterior e posterior, útero e vagina.…”

Drought survival and reproduction impose contrasting selection pressures on maximum body size and sexual size dimorphism in a snake, Seminatrix pygaea

“…It is the smallest semi-aquatic snake in North America, reaching a maximum recorded snout-to-vent length (SVL) of 485 mm (Gibbons and Dorcas 2004), and published interspecific comparisons of SSD among snakes indicate that S. pygaea may be less sexually dimorphic than most other natricine species (e.g., see Appendix 1 in Shine 1994). Like other New World natricines, S. pygaea is viviparous (Sever et al 2000), and mothers typically give birth in late July or early August (Seigel et al 1995b;Winne et al 2005). They rely upon an income breeding strategy to reproduce and nearly all adult females are reproductive in years when the wetland holds water through parturition (Winne et al 2006b).…”