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Maria Gregori - One of the best experts on this subject based on the ideXlab platform.

  • new findings of pleistocene fossil turtles geoemydidae kinosternidae and chelydridae from santa elena province ecuador
    PeerJ, 2017
    Co-Authors: Edwin A Cadena, Juan Abella, Maria Gregori
    Abstract:

    New Pleistocene fossilized turtle remains from five localities of western Ecuador (Santa Elena Province) are described here. All these shell (carapace and plastron) fossil remains come from the Tablazo Formation and belong to three different lineages of cryptodires ("hidden-necked" turtles). The most abundant remains belong to geoemydids, attributed here to the genus Rhinoclemmys (indeterminate species). Less abundant in occurrence are the kinosternidids, attributed to Kinosternon (indeterminate species), and the first fossil record of chelydrids, Chelydra(indeterminate species), in the entirety of Central and South America.

Gregori D Maria - One of the best experts on this subject based on the ideXlab platform.

John L. Carr - One of the best experts on this subject based on the ideXlab platform.

  • Conservation Genetics of the Common Snapping Turtle (Chelydra serpentina)
    Conservation Biology, 1996
    Co-Authors: Christopher A. Phillips, Walter W. Dimmick, John L. Carr
    Abstract:

    Previous studies of relationships among the subspecies of snapping turtles (Chelydra serpentina} based on morphological and osteological characters have been inconclusive. We investigated relationships among the four currently recognized subspecies using restriction endonuclease fragment patterns of mtDNA and protein electrophoresis. Sixteen six-based recognizing restriction endonucleases yielded 90 variable fragments that define 11 different haplotypes. Individuals of the two North American subspecies, C. s. osceola and C. s. serpentina, are closely related, differing by a maximum of 0.5% sequence divergence. The Central American subspecies, C. s. rossignonii and C. s. acutirostris, are more distinct, both from each other (a minimum of 1.7% sequence divergence) and from the North American samples (an average of 4.45% sequence divergence). The degree of allozymic variation among the four subspecies was found to be limited and could not be used to diagnose the four recognized subspecies. The mtDNA data presented here support the species-level distinctness of C. s. rossignonii and C. s. acutirostris from each other and from a C. s serpentina-C. s. osceola complex. The recognition of three distinctive groups of Chelydra rather than one widespread polytypic species has important conservation implications because it focuses attention on the poorly known middle and South American species. Estudios previos sobre las relaciones entre las subespecies de la tortuga Chelydra serpentina, basados en caracteres morfologicos y osteologicos no han sido concluyentes. En el presente estudio investigamos la relacion entre cuatro subespecies reconocidas en la actualidad usando patrones de fragmentos de endonucleasas de restriccion de ADN mitocondrial y electroforesis de enzimas. Dieciseis endonucleasas de restriccion que reconocen 6 bases proveyeron 90 fragmentos variables que definen 11 haplotipos diferentes. Los individuos de dos especies de Norte America, C. s. osceola y C. s. serpentina, estan relacionados estrechamente, difiriendo en un maximo de 0.5% de divergencia de secuencias. Las especies de America Central, C. s. rossignonii y C. s. acutirostris, son mas distintas entre si (con un minimo de 1.7% de divergencia de secuencias) y distintas del complejo C. s. serpentina-C. s. osceola. El reconocimiento de tres grupos distintivos de Chelydra en lugar de una especie politipica de amplia distribucion tiene importantes implicaciones para la conservacion, debido a que enfoca la atencion en las especies menos conocidas de Meso y Sud America.

Hansvolker Karl - One of the best experts on this subject based on the ideXlab platform.

Edwin A Cadena - One of the best experts on this subject based on the ideXlab platform.

  • new findings of pleistocene fossil turtles geoemydidae kinosternidae and chelydridae from santa elena province ecuador
    PeerJ, 2017
    Co-Authors: Edwin A Cadena, Juan Abella, Maria Gregori
    Abstract:

    New Pleistocene fossilized turtle remains from five localities of western Ecuador (Santa Elena Province) are described here. All these shell (carapace and plastron) fossil remains come from the Tablazo Formation and belong to three different lineages of cryptodires ("hidden-necked" turtles). The most abundant remains belong to geoemydids, attributed here to the genus Rhinoclemmys (indeterminate species). Less abundant in occurrence are the kinosternidids, attributed to Kinosternon (indeterminate species), and the first fossil record of chelydrids, Chelydra(indeterminate species), in the entirety of Central and South America.