Proganochelys
| Proganochelys Temporal range: Late Triassic
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Fossil
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| Genus: | Proganochelys
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Proganochelys is the oldest turtle species discovered to date, known only from fossils found in Germany and Thailand in strata from the late Triassic, dating to approximately 210 million years ago. It has several synonymns, including Chelytherium ("Turtle Beast"), Psammochelys ("Sand Turtle"), Stegochelys ("Roof Turtle") and Triassochelys ("Triassic Turtle"). Until relatively recently it was popularly known by the last name.
In life it was about 1 m long, its overall appearance resembling modern turtles in many respects: it lacked teeth, likely had a beak and had the characteristic heavily armored shell formed from bony plates and ribs which fused together into a solid cage around the internal organs. There are some notable differences compared to modern turtles, however: its long tail had spikes and terminated as a club, its head could not be retracted under the shell, and its neck was protected by small spines. While it lacked teeth, it did have "small denticles that formed a pavement over some of the bones of the palate".
Because of its generally advanced characteristics however, most biologists feel that Proganochelys, while the oldest known turtle found thus far, cannot be the oldest turtle species and thus it is quite possible even older fossils may one day be found.