Biometrical and histometrical observations on the testis and epididymis of the African sideneck turtle (Pelusios castaneus (original) (raw)
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In this study we review the macro and microscopic description of the reproductive system of male and female Podocnemis lewyana neonates of 3.5 months of age. We found macroscopic differences in the morphology of the gonads, with ovaries being twice longer that testes, and testes being twice wider than ovaries. Microscopically we identified several immature elements, such as the lack of muscle layer in the oviduct of reptile females, and simple epithelia instead of pseudostratified epithelia in the oviduct and epididymis described in adults. We also describe a black pigment observed macroscopically in the mesovarium and macroscopically and histologically in the epididymis. This pigment is compatible with the center of melano-macrophages described in other vertebrates. Finally we described a supporting mesenchymal structure, the appendage of the oviduct, with was much longer than what has been described in other Podocnemis species.
Zoology, 2008
Sex identification in young sea turtles is challenging. Sea turtle neonates lack external dimorphic characteristics and heteromorphic sex chromosomes. We compared the morphology of the gonads and reproductive ducts of dead formalin-preserved hatchling and post-hatchling Caretta caretta, Dermochelys coriacea, and Chelonia mydas and identified sex-specific differences in these structures that are useful in assigning sex. We tested 11 gross gonadal and reproductive duct characteristics in 57 neonate sea turtles and verified the sex by histological examination. A suite of four characters was found to reliably indicate sex in the three species considered: paramesonephric duct size, mobility of the duct, presence of a complete lumen and gonad mobility. Additionally, gonad shape and edge form were dependable sex-specific characters in cheloniids but not in D. coriacea. Together, these morphological characteristics provide new and reliable methods to quickly distinguish sex in preserved neonate sea turtles without using more extensive histological methods. (J. Wyneken).
Histological findings of sperm storage in green turtle (Chelonia mydas) oviduct
Scientific Reports
Green turtles (Chelonia mydas) are seasonal breeders with a time lag between mating and nesting periods. We therefore investigated whether female turtles store sperm like some other animals by histologically and ultrastructurally analyzing oviducts collected from three mature female free-ranging green turtles during the breeding season in the Ogasawara Islands, Japan. The oviduct comprised an infundibulum, magnum, isthmus, uterus, and vagina. Sperm was found in the isthmus of all turtles examined. Some spermatozoa were found in the duct and acini of glands in the isthmus of two turtles with oviducts containing eggs, and a few were also located in the transition area between the uterus and vagina of one of the turtles. On the other hand, we also found abundant spermatozoa on the luminal surface of the isthmus of one turtle captured during mating. In most reptiles, fertilization occurs in the infundibulum or albumen region, and thus the isthmus near those areas might be suitable for s...
Journal of Morphology, 2003
The germ cell development in the slider turtle (Trachemys scripta) testis was investigated by viewing the histology of the seminiferous epithelium in plastic sections with a light microscope. Germ cell morphologies in the slider turtle testis were similar to the morphologies of other vertebrate germ cell types. However, the slider turtle seminiferous epithelium contained germ cells that progress through spermatogenesis in a temporal rather than a spatial pattern, resulting in a single spermatogenic event that climaxed with one massive sperm release in November. Mature sperm then are stored within the epididymis until breeding commences in the following spring. The germ cell development strategy in the slider turtle is different from that of other amniotes and is more reminiscent of the developmental strategy found in the anamniotic testis. This temporal progression of germ cells through spermatogenesis within a tubular testis represents a transitional model that may be evolutionarily significant.
Chelonian Conservation and Biology, 2006
Gonads and accessory ducts of 140 live, captive-raised juvenile Erymnochelys madagascariensis (72-375 g body mass) of 1-3 years of age as well as those of some wild, larger turtles were investigated by endoscopy. The gonads of all examined turtles could be visualized by endoscopy and unambiguously identified as testes or ovaries. Of the captive-raised juveniles, 75% were females and 25% males. One-year-old females have small, thin, transparent ovaries with transparent, whitish follicles and thin oviducts. Follicles in 2-year-old females increase in number and appear as transparent, whitish flat discs and the oviducts become broader and transparentwhitish to whitish. Three-year-old females have yellowish-whitish follicles and whitish oviducts. Juvenile females over 0.5 kg body mass have yellow follicles and white oviducts. A 1-year-old male and 2 small 2-year-old males show testes of rose pink-whitish color and transparent epididymes. Other 2-year-old males have yellowish-orange testes and in males. 130 g body mass, the epididymes turn transparent-whitish. Three-year-old males have yellow-orange testes that are thicker and rounder, and whitish epididymes with meandering ducti epididymides. The developmental changes of juvenile reproductive tracts seem to depend more on age than on size.
En este estudio se realizó una descripción macro y microscópica del sistema reproductivo de tortugas de Podocnemis lewyana de 3,5 meses de edad. Se hallaron diferencias macroscópicas en las gónadas, microscópicamente se identificaron varios elementos inmaduros. También se describe un pigmento negro observado macroscópicamente en el mesoovario de las hembras, y macroscópica e histológicamente en el epidídimo de los machos, y una estructura mesenquimatosa de soporte que identificamos como el apéndice del oviducto, la cual fue mucho más larga que las descritas en otras especies de Podocnemis.
2008
Sea turtles exhibit sexual dimorphism only as adults, hence diagnosing the sex of hatchlings and juveniles requires the employment of different techniques that vary in their level of accuracy and costs. In order to validate the observation of external gross morphology of gonads as a sexing method for juveniles, we compared results obtained in this way with those obtained through histology in 99 loggerhead turtles with curved carapace length (CCL) ranging from 24.0 to 69.0 cm, found in the Adriatic Sea and in the central Mediterranean. Sex was correctly diagnosed in 92.9% of the 99 cases. The highest error rate due to wrong or uncertain sexing was found in turtles with a CCL less than 30.0 cm (33.3%). In turtles with a CCL of 30.0-40.0 cm and 40.0-50.0 cm, the error rates were low (5.3% and 6.7%, respectively), while no errors occurred in larger individuals (CCL greater than 50.0 cm). The results show that gonadal morphology is a reliable sexing method for large juveniles, but for those of less than 30 cm CCL we recommend verification by histology.
Journal of King Saud University - Science, 2017
Testicular samples were collected from African sideneck turtles (Pelusios castaneus) at the peak of spermiogenesis in order to describe spermatid acrosomal vesicle formation and nuclear morphogenesis. Acrosomal vesicle formation commences with a Golgi transport vesicle attaching to a round spermatid, followed by the emergence of an acrosome granule. This is followed by the development of the subacrosomal space, which becomes enlarged as nuclear elongation and condensation continue. The round spermatid elongates and the emerging elongating spermatid successively becomes surrounded by circular, longitudinal and slanting microtubules of the manchette. The acrosomal vesicle becomes visible with an acrosome granule resting on the base of the electron dense material. Acrosomal vesicle morphogenesis in the African sideneck turtle results in a highly compartmentalized acrosome divisible into the acrosomal cortex and medulla. The future position of the flagellum starts to develop, being encircled by mitochondria while the distal centriole becomes obvious and the emerging flagellum grossly divisible into the connecting piece, midpiece, principal piece and endpiece. Although acrosomal vesicle formation and nuclear morphogenesis during spermiogenesis in the turtle are consistent with other reptilian species, a few differences were observed. The major difference observed was the formation of a single acrosome granule, which manifests prior to the attachment of the acrosomal vesicle to spermatid nucleus. The other differences observed were the emergence of two endonuclear canals in the elongating spermatid and the presence of slanting microtubules of the manchette. The observed developmental variations are expected to be valuable in future phylogenetic studies and potentially serve to test certain hypotheses concerning the reproductive status of turtle species. Findings from this study add to the growing database of spermatid morphology in turtles, thereby providing insights into variations in mature sperm morphology in the species.
Ultrasound Imaging of the Inguinal Region of Adult Male Loggerhead Sea Turtles (Caretta caretta)
Journal of Zoo and Wildlife Medicine, 2010
The biology and reproductive anatomy of male loggerhead sea turtles (Caretta caretta) have been difficult to study. The principle method for evaluation of the coelomic cavity in both adult and juvenile male sea turtles is celioscopy. The purpose of this study was to describe the technique and structures seen when scanning the inguinal region of live, wild-caught, adult male loggerhead sea turtles and to compare these findings to those resulting from celioscopy and necropsy. Twenty-one adult male loggerhead sea turtles were collected by trawling in the Cape Canaveral shipping channel in April 2007. All turtles were placed in dorsal recumbency and imaged with a Sonosite 180 Vet Plus (Sonosite, Inc., Bothell, Washington 98021, USA) and a microconvex, 4-7-MHz curvilinear array probe. The inguinal region was divided into four quadrants: cranial, lateral, medial, and caudal. Celioscopy was performed on 13 turtles, and biopsies were obtained of the testes and the epididymides to confirm correct identification of the structures. In the cranial aspect of the inguinal region, the urinary bladder and large and small intestines were identified. In the lateral inguinal region, the lung and kidney were seen. In the medial aspect of the inguinal region, the testis and epididymis were routinely identified. In the caudal aspect of the inguinal region, the coxofemoral joint was seen. A small learning curve was required; however, correlation with celioscopy and biopsy showed that consistent, repeatable identification of caudal coelomic structures was easily achieved. Ultrasound provided an inexpensive, rapid, noninvasive method to evaluate the reproductive anatomy of live-captured, male loggerhead sea turtles.