|Named By:||Georg Baur in 1887|
|Time Period:||Late Triassic, 210 Ma|
|Location:||Germany - Lowenstein Formation & Trossingen Formation, Greenland - Fleming Fjord Formation, and Thailand - Huai Hin Lat Formation|
|Size:||About 1 meter long|
|Classification:||| Chordata | Reptilia | Anapsida | Testudines ||
|Also known as:||| Chelytherium | Psammochelys | Stegochelys | Triassochelys ||
Proganochelys quenstedti is the oldest stem-turtle species with a complete shell 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.
Psammochelys, Stegochelys, and Triassochelys are junior synonyms of Proganochelys. Chelytherium von Meyer, 1863 has been considered a synonym of Proganochelys by some authors, but Joyce (2017) considers it a nomen dubium given the fragmentary nature of the syntype material. Joyce (2017) also considered North American genus Chinlechelys to be a junior synonym of Proganochelys, though the author maintains the type species of the former genus, C. tenertesta, as a distinct species within the genus Proganochelys.