Protoginglymostoma is a ginglymostomatid shark from late Cretaceous Montana, USA.
Paleoecology[]
Protoginglymostoma lived in shallow waters, moving up the river in the Hell Creek Formation. The animal was sluggish, and was likely benthic. Protoginglymostoma also may have been nocturnal like modern nurse sharks. Protoginglymostoma occurs earliest in the Ypresian (the namesake of P. ypresiensis) Fishburne Formation.