Fossil from oldest ancestor of modern sea turtles

Date: October 3, 2016

Source: University of Alabama at Birmingham

Several 80-million-year-old fossils found in Alabama are from a species of sea turtle that is the oldest known member of the lineage that gave rise to all modern species of sea turtle, according to new research from the University of Alabama at Birmingham.

Researchers from the College of Arts and Sciences' Department of Biology worked with two relatively complete turtle skeletons, along with several smaller pieces, that are housed at Birmingham's McWane Science Center, to unearth the evolutionary clues tying the ancient turtles to modern sea turtles, and confirm the existence of that ancient species, previously known only from a few isolated fragments.

The McWane fossils help solve a long-standing debate as to whether this animal was a unique species. They also provide insights into the evolutionary history of living species of sea turtles, including the Kemp's Ridley, Loggerhead and the endangered Green sea turtle.

According to research published in the Journal of Systematic Palaeontology, the fossils belong to Ctenochelys (tee-no-key-lees) acris, a marine-adapted turtle that lived in the shallow, subtropical sea that once covered most of Alabama. By dating the rock formation from which these fossils were recovered, C. acris is presumed to have lived more than 80 million years ago, during the Late Cretaceous, a period of time when sea turtle diversity was at an all-time high.

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