Protostegidae

Protostegids Temporal range: Cretaceous,[1][2] Valanginian–Maastrichtian PreꞒ Ꞓ O S D C P T J K Pg N
Life restoration of Archelon ischyros
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Testudines
Suborder:	Cryptodira
Clade:	Panchelonioidea (?)
Family:	†Protostegidae Cope, 1873 [3]
Type species
†Protostega gigas Cope, 1872
Genera
†Archelon †Atlantochelys †Bouliachelys †Calcarichelys †Chelosphargis †Cratochelone †Desmatochelys †Iserosaurus †Kansastega †Notochelone †Protostega †Rhinochelys †Santanachelys[4] †Teguliscapha †Terlinguachelys †Pneumatoarthrus †Ocepechelon

Protostegidae is a family of extinct marine turtles that lived during the Cretaceous period. The family includes some of the largest sea turtles that ever existed. The largest, Archelon, had a head one metre (39 in) long. Like most sea turtles, they had flattened bodies and flippers for front appendages; protostegids had minimal shells like leatherback turtles of modern times.