Paleontologists have found a new species of turtle in Colorado and have dated it right to the Cretaceous-Paleocene boundary. This indicates that it may have survived the major extinction event that wiped out non-avian dinosaurs among many other species.
Tavachelydra stevensoni, described in a Paper published in the Swiss Journal of Paleontology, had a 1.5-foot long shell. That made it one of the larger turtles at the time in its region. Studying the specimen could reveal clues about what attributes may have been helpful in surviving the extinction event.
Tavachelydra stevensoni, gen. et sp. nov., DMNH EPV.141854 (DMNH Loc.19258), holotype, photograph overlain by line drawing of the sulci and photographs of the lateral edges of peripherals showing anteroposterior changes in cross sectional shape of peripherals. Lateral photos of peripherals were taken on the rostral edge and are oriented with their medial side up and the dorsal side to the right
Anatomy reveals clues about diet
“Isolated pan-chelydrid turtle shell fragments are common in Late Cretaceous and early Paleocene sediments across western North America,” write the researchers, “but more complete and associated specimens are rare, obfuscating our understanding of the group’s early evolution”
The fossil was found in laminated fine-grained deposits. This suggests that the creature inhabited ponded-water environments. Further, its cranial material indicated a durophagous diet.
Diet reveals clues about survival
T. stevensoni‘s survival suggests that durophagy was an important feeding strategy during the early Paleocene, and also a survival strategy. The scientists noted earlier studies that had found that “turtle taxa with a durophageous diet have a higher survivorship across the K/Pg mass extinction compared to turtles with a non-durophageous diet”
Tavachelydra stevensoni, gen. et sp. nov., DMNH EPV.143100 (DMNH Loc. 20,053), referred carapace. A, photograph and B, interpretive line drawing in external view. C, photograph and D, interpretive line drawing in internal view.
This find expands our view of turtle evolution, showing that relatively early turtles were exploring extreme feeding strategies and morphologies. It also enhances our view of Cretaceous freshwater ecosystems