Functional morphology and biochemistry of reptilian oviducts and eggs : implications for the evolution of reproductive modes in tetrapod vertebrates /

Palmer, Brent D.

doi:10.5962/bhl.title.48740

Cited by 8 publications

(2 citation statements)

References 145 publications

(420 reference statements)

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“…in the exact same position as they were found). This belief most likely stems from the observation that reptilian eggs lack the avian chalazae 19 20 . In the absence of specific experimental studies, whether this belief belongs to the “urban myth” category or is indeed true remains an open question.…”

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confidence: 99%

Myth busting? Effects of embryo positioning and egg turning on hatching success in the water snake Natrix maura

Aubret

Blanvillain

Kok

2015

Sci Rep

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It is a common belief that reptile eggs should not be turned after oviposition once the embryo has attached itself to the inner membrane of the shell as it might kill developing embryos. Here, we used 338 eggs from 32 clutches of the water snake Natrix maura to (1) thoroughly describe natural clutch arrangement, (2) experimentally assess the effects of natural embryo positioning and (3) egg turning on embryo metabolism, hatching success, and hatchling phenotype. Clutches contained, on average, 59% of embryos located at the top, 28% at the bottom, and 14% on a side of the egg. Larger females laid larger clutches with higher proportion of top located embryos. Top embryos displayed higher metabolic rates (heart rates), shorter incubation time, and produced lighter and shorter snakes than bottom embryos. Egg turning did not significantly influence egg development, hatching success or hatchling phenotypes. However, post-birth mortality was significantly higher in turned (37.5%) compared to unturned (4.5%) embryos, providing support to the common belief that eggs should not be moved from their natural position.

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confidence: 99%

Myth busting? Effects of embryo positioning and egg turning on hatching success in the water snake Natrix maura

Aubret

Blanvillain

Kok

2015

Sci Rep

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“…The tube region of the alligator oviduct is similar in functional morphology to the avian magnum, whereas the fiber-secreting region of the uterus and the calcium-secreting region of the uterus are homologous to the avian isthmus and shell gland, respectively. Although the tube of the alligator is similar in morphology to that of a bird, the proteins secreted from this region are unique when compared to birds (Palmer, 1990;Palmer and Guillette, 1992). For example, ovalbumen, a major component of…”

Section: Tor Mississippiensis Oviduct Reproductionmentioning

confidence: 99%

Localization of insulin‐like growth factor‐I‐like immunoreactivity in the reproductive tract of the vitellogenic female American alligator, Alligator mississippiensis

Cox

Guillette

1993

Anat. Rec.

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Insulin-like growth factor I (IGF-I) is a 70 amino acid, mitogenic polypeptide, which, in mammals, acts through an endocrine, paracrine, and/or autocrine pathway to regulate growth and development. The primary goal of this study was to determine whether or not IGF-I-like immunoreactivity is present in the oviduct of the vitellogenic American alligator, Alligator mississippiensis, and if immunoreactivity patterns vary among the three functional oviducal regions: the albumen-secreting tube region, the anterior, fiber-secreting uterus, and the posterior, calcium-secreting uterus. Immunolocalization of IGF-I-like immunoreactivity was accomplished using a polyclonal antihuman rabbit antiserum with an immunoperoxidase staining system. IGF-I-like immunoreactivity was detected in all three oviducal regions of the vitellogenic alligator. The presence of IGF-I-like immunoreactivity in the oviduct suggests this hormone could function in the growth and proliferation of the alligator oviduct. Furthermore, the presence of IGF-I-like immunoreactivity in the tubal glands, which secrete components of the egg white, suggests that growth factors such as IGF-I may be synthesized by these glands and incorporated into the albumen during egg formation.

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Morphological changes in the oviductal endometrium during the reproductive cycle of the tortoise,Gopherus polyphemus

Palmer

Guillette

1990

Journal of Morphology

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The oviducts of 24 tortoises (Gopherus polyphemus) were examined using histological techniques and scanning electron microscopy to determine endometrial morphology. Measurements of endometrial characteristics (epithelial cell height, cilia length, thickness of endometrial glandular layer, and glandular diameter) in the uterus and tube (tuba uterina) were obtained to determine changes during the reproductive cycle. Epithelial cell height increases in both the uterus and the tube during vitellogenesis and remains hypertrophied during gravidity. Cilia length increases in the uterus during late vitellogenesis and gravidity, but the length of tubal cilia does not change during the reproductive cycle. The ratio of secretory to ciliated epithelial cells in the oviduct increases from quiescence to gravidity. The thickness of the glandular endometrial layer increases in both the uterus and tube during vitellogenesis. In the uterus, the glandular layer decreases in thickness during gravidity. The diameter of the uterine glands increases throughout vitellogenesis and gravidity; however, following ovulation glandular cells become depleted of secretory granules and cell height diminishes. The diameter of the tubal glands is unchanged during the reproductive cycle. Oviductal hypertrophy during vitellogenesis coincides with elevated circulating estradiol, whereas during gravidity progesterone concentrations peak (Taylor, '82, PhD Dissertation, University of Florida, Gainesville) and may induce secretion of albumen and eggshell components.

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Functional morphology and biochemistry of reptilian oviducts and eggs : implications for the evolution of reproductive modes in tetrapod vertebrates /

Cited by 8 publications

References 145 publications

Myth busting? Effects of embryo positioning and egg turning on hatching success in the water snake Natrix maura

Myth busting? Effects of embryo positioning and egg turning on hatching success in the water snake Natrix maura

Localization of insulin‐like growth factor‐I‐like immunoreactivity in the reproductive tract of the vitellogenic female American alligator, Alligator mississippiensis

Morphological changes in the oviductal endometrium during the reproductive cycle of the tortoise,Gopherus polyphemus

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