Family Platylepadidae Newman & Ross, 1976

Diagnosis (after Ross & Frick 2011: 62)

Wall six-plated (R-CL1-CL2-C) or eight-plated in juvenile specimens (R-RL-CL1-CL2-C); relatively thin; parietes each with midrib and/or tooth; longitudinal tubes when present external (internal in Chelolepas); apertural hood absent (except in Chelolepas); primary or internal lamina (including the sheath) solid, outer lamina (when present) formed by joining of longitudinal T-shaped flanges extending from inner wall, thus forming external longitudinal canals.

Included subfamilies

Platylepadinae Newman & Ross, 1976; Calyptolepadinae Frick, Zardus & Lazo-Wasem, 2010; Chelolepadinae Frick & Ross, 2011; Cylindrolepadinae Frick & Ross, 2011; Stomatolepadinae Frick & Ross, 2011 .