23.7.14

Sobre la distribución de Neochelys en la 15 edición del congreso Gondwana


Y vamos con otro de los trabajos que tienen que ver con la paleontología de vertebrados y que fue presentado en el congreso Gondwana 15. La intervención “On the debatable generic assignment of the African “Podocnemisfajumensis and the endemism of Neochelys” se resumió de la siguiente manera:

Pelomedusoides is a clade of turtles that originated in Gondwana. It experienced a major radiation during the Early Cretaceous, resulting in several groups, such as the abundant and diverse Podocnemididae (Lapparent de Broin, 2000a). Podocnemididae is currently represented by the South American Podocnemis and Peltocephalus dumerilianus, and the African Erymnochelys madagascariensis.

The African record of Podocnemididae is relatively abundant, with sites in several countries, corresponding to different stages of its geological history. The Fayum Depression, in Egypt, is the area where the greatest diversity has been recorded in both the Eocene and Oligocene (Lapparent de Broin, 2000b). From the early Oligocene here, Andrews (1903) defined Podocnemis fajumensis from the anterior region of a plastron. Other partial and relatively complete shells were recognized in subsequent papers, including those of its junior synonym “Podocnemis blanckenhorni” (e.g. Reinach, 1903; Andrews, 1906).

The attribution of “P.” fajumensis to Podocnemis cannot be supported. Lapparent de Broin (2000b) recognized it as belonging to an undescribed genus, related to Erymnochelys (aff. Erymnochelys fajumensis). Gaffney et al. (2011) identified, for the first time, the presence of skulls associated with shells of “P.” fajumensis. They admitted that its shell is very similar to that of Erymnochelys, showing differences with the European Eocene Neochelys. Neochelys is an abundant and diverse taxon. However, only a deformed skull, corresponding to the French N. arenarum, had been thoroughly figured as attributed to this genus. Gaffney et al. (2011) considered the skull of “P.” fajumensis as hardly distinguishable from that of N. arenarum, proposing the new combination Neochelys fajumensis.

The analysis of the so far published material of Neochelys, and the study of abundant new cranial and postcranial specimens, allow us to review the anatomy of each of the known species, and to propose a new generic diagnosis. As a result, Neochelys is recognized as exclusively distributed in the Eocene of Europe. Numerous differences in both the cranial and postcranial skeleton are identified between Neochelys and “Podocnemisfajumensis. Therefore, this African species cannot be attributed to Neochelys, being identified as a possible member of the Erymnochelys group.


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Más información:
  • Referencia: Pérez-García, A.; de Lapparent de Broin, F. 2014. On the debatable generic assignment of the African “Podocnemisfajumensis and the endemism of Neochelys. In: Pankhurst, R.J., Castiñeiras, P., Sánchez Martínez, S. (Eds.). Abstract Book of Gondwana 15, North meets South: 138.
  • Imágenes: En la superior, cráneo del podocnemídido del Eoceno europeo Neochelys arenarum, en la inferior, holotipo de la pleurodira del Neogeno europeo Neochelys liriae.