Male genital system of Ameiva ameiva (Squamata: Teiidae).

Understanding squamate reproductive morphology is crucial for investigating ecological, behavioral, and evolutionary questions. Here, we describe the anatomy and histology of the male genital system of Ameiva ameiva from southeastern Brazil. Ten adult males were dissected to characterize genital macroscopy and collect fragments of the testes, gonadoducts, and kidneys for histological examination. We examined 10 transverse histological sections per individual and measured the epithelial height of the epididymis and ductus deferens. The male reproductive system consists of a pair of yellowish oval testes, the rete testis, ductuli efferentes, epididymis, ductus deferens, ampulla ductus deferentis, sexual segment of the kidney (SSK), cloaca, and hemipenis. The hemipenis is elongated, cylindrical, and unilobed, with a sulcate face and an asulcate face, which has continuous fringes throughout its length. Seminiferous tubules exhibited germ cells at various stages. The epididymis is wider and more coiled than the ductus deferens. The rete testis has a simple squamous epithelium with long stereocilia, while the narrower ductuli efferentes are lined by a simple ciliated cuboidal epithelium. The epididymal epithelium is pseudostratified columnar, with basal and ciliated principal cells, whereas the ductus deferens epithelium is pseudostratified to simple cuboidal. The epididymal epithelium is 1.5 times taller than the ductus deferens epithelium. Here, we observed the SSK present in the cortex of the ventral region of the kidneys due to the hypertrophy of the distal convoluted tubules, as well as its secretory activity. Our findings will contribute to future research into the evolution of squamate reproductive morphology.

Ultrasonographic and radiographic evaluation of gestation in golden lanceheads (Bothrops insularis) in ex situ breeding programs.

The golden lancehead (Bothrops insularis) is a critically endangered snake endemic to Queimada Grande Island, southeastern Brazil. Captive breeding programs are vital for the conservation of this species. This study evaluates the gestation of two females golden lanceheads using radiography and ultrasonography. The first female was collected on the island while reproductively active (late vitellogenesis or early pregnancy) and kept in captivity. This female gave birth to five neonates after an 8-month gestation period, which is longer than estimates based on specimens preserved in museums. The second female copulated in captivity in July and probably ovulated in October. In this case, no embryonic development was detected, and the female deposited 14 undeveloped eggs approximately 6 months after ovulation.

Reproductive cycles of neotropical boid snakes evaluated by ultrasound.

Snakes have increasingly been bred as pets around the world. Few studies have addressed the reproduction of boid snakes, and no study has addressed their reproductive cycles in captivity. Thus, this paper describes the reproductive aspects of Brazilian boids in captivity. We used ultrasonography to characterize the reproductive cycle of four boid species in captivity in the Southern Hemisphere: the anaconda (Eunectes murinus), the red-tailed boa (Boa constrictor constrictor), the Amazon tree boa (Corallus hortulanus), and the rainbow boa (Epicrates cenchria). Nonvitellogenic follicles occurred from January to December in anaconda and red-tailed boa and for a shorter period from September to February in Amazon tree boa and from January to May in rainbow boa. Vitellogenesis occurred from late June to late March in E. murinus in year-round (12 months), from March to March in Amazon tree boa, from late September to late March in red-tailed boa, and from late March to late September in rainbow boa. Mating occurred from late March to late September in red-tailed boa and rainbow boa and from late September to late March in Amazon tree boa. No mating was observed in anacondas, but a female probably underwent parthenogenesis. Births occurred in July in anaconda and in March to July in Amazon tree boa and from December to March in red-tailed boa and rainbow boa. In males, increases in testicular size were associated with the mating season. Ultrasonography proved to be a safe and noninvasive technique to study the reproductive cycle of giant snakes in captivity.

Short-term cold storage of seminal samples of the golden lancehead pitviper (Bothrops insularis).

Assisted reproductive technologies such as cooling, freezing, and artificial insemination are essential in conserving genetic diversity of critically endangered reptiles like the golden lancehead pitviper (Bothrops insularis). Therefore, we examined viability of semen samples from captive golden lanceheads diluted in coconut-water based extender over a 48-h period of cooling (5°C). Semen evaluations were performed immediately after the dilution and at 6, 24, and 48 h, using computer-assisted sperm analysis and stains to assess plasma membrane and acrosomal status. Our findings showed that the extender and protocol employed here were effective in preserving golden lancehead pitviper spermatozoa for a short periods of time (48 h), allowing semen samples to be transported to distant locations for immediate use without the setbacks of cryopreservation.

How Does Oocyte Uptake Occur? A Macroscopic Study of the Ovarian and Oviductal Modifications for Egg Capture in the Coral-Snake Micrurus corallinus.

The processes of follicular development, ovulation, egg capture, and egg transport vary among vertebrates. Therefore, analysis of the reproductive tract of several lineages is needed for understanding the evolutionary changes of the reproductive system. In turtles, the ovulated eggs are released into the coelomic cavity and taken up by one of the two oviducts, a phenomenon called extrauterine migration of eggs. However, the process of egg uptake in lizards is different. The egg is ovulated directly into the infundibulum, and oocyte uptake by the contralateral oviduct rarely occurs. The same pattern has been hypothesized to occur in snakes. To test this hypothesis, we analyzed the reproductive tract of female Micrurus corallinus preserved in zoological collections. We examined the anatomical characteristics of the infundibulum and ovary and compared the reproductive output between the ovaries to verify the mechanism of egg capture and the anatomical viability of extrauterine migration of eggs. The reproductive output of the right ovary was higher than that of the left ovary, and the higher number of eggs in the right oviduct is due exclusively to the production of the ipsilateral ovary. Several anatomical features prevent extrauterine migration of eggs, including the asymmetry of the reproductive system, the arrangement of the ovarian follicles in a single row, and the formation of a wrapping around the ovary and infundibulum by the visceral pleuroperitoneum membrane (preventing against ectopic eggs). Therefore, the hypothesis of egg capture by the contralateral oviduct is anatomically infeasible in M. corallinus and possibly in other snakes. Anat Rec, 301:1936-1943, 2018. © 2018 Wiley Periodicals, Inc.