New material of the platychelyid turtle Notoemys zapatocaensis from the early cretaceous of colombia; implications for understanding pleurodira evolution

Notoemys zapatocaensis is the youngest representative of the Platychelyidae, a group of Late Jurassic-Early Cretaceous pleurodires. Here we describe two new specimens of this species represented by a partial carapace and a nearly complete articulated shell. Notoemys zapatocaensis is different from o...

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Detalles Bibliográficos
Autores Principales: Cadena, Edwin A., Jaramillo, Carlos A., Bloch, Jonathan I.
Formato: Capítulo de libro (Book Chapter)
Lenguaje:Inglés (English)
Publicado: Springer 2012
Materias:
Acceso en línea:https://repository.urosario.edu.co/handle/10336/28872
https://doi.org/10.1007/978-94-007-4309-0_8
Descripción
Sumario:Notoemys zapatocaensis is the youngest representative of the Platychelyidae, a group of Late Jurassic-Early Cretaceous pleurodires. Here we describe two new specimens of this species represented by a partial carapace and a nearly complete articulated shell. Notoemys zapatocaensis is different from other platychelyid turtles in having: (1) two fairly reduced lateral tuberosities on the margin of the anterior plastral lobe, (2) a shallow notch on the posterolateral margin of the epiplastra, giving a convex posterolateral edge to this bone, (3) gular scales that are rectangular in shape and much wider than long, (4) a long intergular scale that has a slight medial contact with the pectorals, resulting in a complete separation of the humeral scales, (5) a central plastral fontanelle that projects posteriorly into the xiphiplastral region, (6) a very small marginal 3, (7) a slightly shorter neural 1 than neural 2, with an exclusive lateral contact with costal 1, resulting in a complete separation of neural 2 and costal 1, (8) narrower vertebral scales, and (9) peripheral 3 lacking a posteromedial contact with costal 2. Phylogenetic analysis indicates that N. zapatocaensis is a sister taxon of N. oxfordiensis, and that Proterochersis robusta can be resolved in two different positions in the testudines tree: (1) with Odontochelys semitestacea based on the fact that both taxa share two mesoplastra meeting at midline, or (2) as the most basal pleurodire, based on a suture articulation of pelvis to shell. Anal notch shape and potentially fontanelle size are indicators of sexual dimorphism in platychelyids.