Postdoctoral Fellow Michael Cherney and colleagues published a study of two new turtle specimens from Wadi Al Hitan ("Valley of the Whales") in Egypt. The turtle specimens, which lived across the globe for much of the last 40 million years, better help scientists understand the relationship and ecology of a completely extint group of side-necked sea turtles. These turtles had a bony plate for crushing the shells of their prey and played a critical role in their respective ecosystems.
Find the paper's abstract below:
Abstract — Podocnemidid turtles in the subtribe Stereogenyina are diagnosed by a unique, partially developed secondary palate that consists of a pair of lateral flanges, each formed by the maxilla and palatine, separated by a midline cleft. Two monospecific stereogenyine genera, Stereogenys and Cordichelys, overlap temporally and spatially in the upper Eocene deposits of the Fayum Depression
in Egypt. The taxonomic history of these genera is complicated and intertwined, and the two species (St. cromeri and C. antiqua) may be more closely related than their long history of generic separation suggests. Here we describe two new specimens of Cordichelys—a skull and shell from the lower Priabonian Birket Qarun Formation and a complete skull from the overlying middle Priabonian of the Qasr el-Sagha Formation. We also attribute to Cordichelys a mandible that previously had been tentatively identified as Stereogenys. These specimens along with previously described Cordichelys materials reveal substantial morphological variation within the currently monotypic genus. Presence of Cordichelys in the Birket Qarun Formation corroborates previous interpretations of a marine habitat for these turtles. Meanwhile, the reconstructed shell of the new Birket Qarun specimen reveals moderate doming and an ovoid outline that contrast with previous interpretations of its shape as “flat” and “cordiform.”
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