A Review of the Fossil Record of Nonbaenid Turtles of the Clade Paracryptodira

The fossil record of nonbaenid paracryptodires ranges from the Late Jurassic (Kimmeridgian) to the Paleocene of North America and Europe only. Earlier remains may be present as early as the Middle Jurassic (Bathonian). Only a single dispersal event is documented between the two continents after their breakup during the Cretaceous in the form of the appearance of the Compsemys lineage in the Paleocene of France. Nonbaenid paracryptodires were restricted to freshwater aquatic environments but display adaptations to diverse feeding strategies consistent with generalist, gape-and-suction, and hypercarnivorous feeding. Current phylogenies recognize two species-rich subclades within Paracryptodira, Baenidae and Pleurosternidae, which jointly form the clade Baenoidea. A taxonomic review of nonbaenid paracryptodires concludes that of 34 named taxa, 11 are nomina valida, 15 are nomina invalida, and 8 are nomina dubia.