Photo: Matt Lamanna, CMNH.

This turtle shell is the holotype, or original specimen, of the species “Baena hatcheri,” named by Oliver Hay in 1901. Hay named this specimen after celebrated CMNH paleontologist John Bell Hatcher, who had discovered it earlier that year.

Because this shell shows no unique anatomical features, the species “Baena hatcheri” is no longer considered taxonomically valid. However, recent discoveries have shown that the shell of “B. hatcheri” probably belongs to either Eubaena cephalica or Stygiochelys estesi, turtle species that were originally named for their distinctive skulls. Because it’s difficult to tell the shells of Eubaena and Stygiochelys apart, scientists can’t be sure which of these genera the “Baena hatcheri” shell belongs to. We based our reconstruction of this turtle on the skull of Eubaena and the shell of “B. hatcheri.”

“Baena hatcheri” is a member of an extinct turtle group, the Baenidae, which was very common in Cretaceous ecosystems of North America. Despite persisting for tens of millions of years, baenids have so far been found nowhere else in the world. They appear to have been carnivores or mollusk-eaters that preferentially lived in rivers and streams. Interestingly, baenids survived the mass extinction at the end of the Mesozoic that killed all non-avian dinosaurs, only to disappear a few million years later during the Eocene Epoch.

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