During a survey of the commensal barnacles of nesting and foraging sea turtles from the coastal waters of Florida and Georgia, USA, an undescribed species of platylepadid coronuloid barnacle was encountered, embedded within the carapace and plastron regions of host turtles. This new genus and species is described herein as Calyptolepas bjorndalae gen. et sp. nov. and is compared with other members of the family Platylepadidae. While similar in some respects to members of currently recognized platylepadid subfamilies, particularly Cylindrolepas darwiniana Pilsbry (Cylindrolepadinae Ross and Frick) and Platylepas decorata Darwin (Platylepadidae Newman and Ross), this new species bears an amalgamation of characters from these two subfamilies that require it to be placed into a new subfamily, Calyptolepadinae subfam. nov., also described herein.