†family Protostegidae Cope 1873 (sea turtle)
Reptilia - Testudines - Dermochelyoidae
Parent taxon: Dermochelyoidae according to F. de Lapparent de Broin et al. 2014
Sister taxa: Alienochelys, Bouliachelys, Corsochelys, Dermochelyidae, Dermochelys, Mesodermochelys, Ocepechelon
Subtaxa: Archelon, Chelospharginae, Chelosphargis, Cratochelone, Desmatochelys, Notochelone, Pneumatoarthrus, Protostega, Protosteginae, Santanachelys, Terlinguachelys
Type: Protostega
Ecology: aquatic omnivore