Vertebrate Evolution: The Strange Case of Gymnophionan Amphibians

Exbrayat, Jean-Marie; Raquet, Michel

doi:10.1007/978-3-642-00952-5_4

Cited by 4 publications

(3 citation statements)

References 64 publications

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“…Reproduction and fetal nutrition in viviparous caecilians has been summarized in several reviews (e.g., Wake, , b, 1992a, 1993, 2006; Wake and Dickie, ; Exbrayat, ; Exbrayat and Raquet, ; Greven, ; Gomes et al, ). In all live‐bearing caecilians known, developing embryos pass through a lecithotrophic phase, whereupon they feed on maternal secretions and tissues derived from the oviductal lining.…”

Section: Evolution Of Matrotrophymentioning

confidence: 99%

Evolution of vertebrate viviparity and specializations for fetal nutrition: A quantitative and qualitative analysis

Blackburn

2014

Journal of Morphology

274

339

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Phylogenetic analyses indicate that viviparity (live-bearing reproduction) has originated independently in more than 150 vertebrate lineages, including a minimum of 115 clades of extant squamate reptiles. Other evolutionary origins of viviparity include 13 origins among bony fishes, nine among chondrichthyans, eight in amphibians, one in Paleozoic placoderms, six among extinct reptiles, and one in mammals. The origins of viviparity range geologically from the mid-Paleozoic through the Mesozoic to the Pleistocene. Substantial matrotrophy (maternal provision of nutrients to embryos during pregnancy) has arisen at least 33 times in these viviparous clades, with most (26) of these origins having occurred among fishes and amphibians. Convergent evolution in patterns of matrotrophy is widespread, as reflected by multiple independent origins of placentotrophy, histotrophy, oophagy, and embryophagy. Specializations for nutrient transfer to embryos are discontinuously distributed, reflecting the roles of phylogenetic inertia, exaptation (preadaptation), and constraint. Ancestral features that function in gas exchange and nutrition repeatedly and convergently have been co-opted for nutrient transfer, often through minor modification of their components and changes in the timing of their expression (heterochrony). Studies on functional and evolutionary morphology continue to play a central role in our attempts to understand viviparity and mechanisms of fetal nutrition.

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Section: Evolution Of Matrotrophymentioning

confidence: 99%

Evolution of vertebrate viviparity and specializations for fetal nutrition: A quantitative and qualitative analysis

Blackburn

2014

Journal of Morphology

274

339

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“…Within caecilians, kidney development and structure of adult kidneys present variations from one species to another. Like other organs, variations could be related to the taxonomic position, with basal Asiatic Ichthyophiidae and American Rhinatrematidae showing pronephros and mesonephros in a closer position than modern taxa such as Typhlonectidae (WILKINSON & NUSSBAUM, 2006;EXBRAYAT & RAQUET, 2009), and more specifically such as T. compressicauda.…”

Section: Discussionmentioning

confidence: 99%

Embryonic development of kidneys in viviparous Typhlonectes compressicauda (Amphibia, Gymnophiona)

Bastit

Exbrayat²

2011

Basic Appl Herpetol

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The embryonic development of organs within Gymnophiona is still poorly known. In Typhlonectes compressicauda, a caecilian amphibian expressing a derived viviparous reproductive mode, development can be divided into 34 stages and is characterized by a metamorphosis occurring between stages 30 and 33. At stages 18-19, Wolffian ducts appear in the anterior part of the embryo. At stage 23, a pair of pronephric kidneys is clearly visible with several nephrostomes that empty into the coelomic cavity. At stage 30, pronephroi that were observed at the level of the second and fifth vertebrae are now observed between the 24th and 28th vertebrae. At this stage, several mesonephric tubules appear between the 29th and 32nd vertebrae, and mesonephric tissue is observed in the posterior part of the body. At stage 31, pronephroi begin to disappear. The mesonephroi have now proximal and distal tubules. At stages 32-33, two mesonephroi are visible as a pair of lengthened layers, representing the definitive kidneys.

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“…Moreover, the gymnophionans are amongst the least known amphibians [ 45 , 46 ]; they are interesting for they belong to a homogenous group [ 47 ], presenting a lot of particular characteristics [ 48 , 49 ]. In addition, several species of this group are oviparous, viviparous, or presenting a direct development [ 50 , 51 , 52 ].…”

Section: Introductionmentioning

confidence: 99%

Patterns of Apoptosis and Proliferation throughout the Biennial Reproductive Cycle of Viviparous Female Typhlonectes compressicauda (Amphibia, Gymnophiona)

Raquet

Brun

Exbrayat

2016

IJMS

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Typhlonectes compressicauda is an aquatic gymnophionan amphibian living in South America. Its breeding cycle is linked to seasons, characterized by a regular alternation of rainy and dry seasons. During a complex biennial cycle, the female genital tract undergoes a series of alternations of increasing and decreasing, governed by equilibrium of proliferation and apoptotic phenomena. Immunohistochemical methods were used to visualize cell proliferation with the detection of Ki67 antibody, a protein present in proliferative cells; terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and Apostain were performed to detect apoptotic cells on sections of ovaries and oviducts. In ovaries, both phenomena affect the germinal nests and follicles according to the cycle period. In the oviduct, the balance was in favor of proliferation during preparation for reproduction, and in favor of apoptosis when genital ducts regress. Apoptosis and proliferation are narrowly implicated in the remodeling of the genital tract and they are accompanied by the differentiation of tissues according to the phase of the breeding cycle. These variations permit the capture of oocytes at ovulation, always at the same period, and the parturition after 6–7 months of gestation, at a period in which the newborns live with their mother, protected in burrows in the mud. During the intervening year of sexual inactivity, the female reconstitutes body reserves.

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Vertebrate Evolution: The Strange Case of Gymnophionan Amphibians

Cited by 4 publications

References 64 publications

Evolution of vertebrate viviparity and specializations for fetal nutrition: A quantitative and qualitative analysis

Evolution of vertebrate viviparity and specializations for fetal nutrition: A quantitative and qualitative analysis

Embryonic development of kidneys in viviparous Typhlonectes compressicauda (Amphibia, Gymnophiona)

Patterns of Apoptosis and Proliferation throughout the Biennial Reproductive Cycle of Viviparous Female Typhlonectes compressicauda (Amphibia, Gymnophiona)

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