Family Platylepadidae Newman & Ross, 1976: 44

(nom. transl. Ross & Frick, 2007: 3)

Type genus. Platylepas Gray, 1825; by original designation of Newman & Ross (1976: 44).

Diagnosis. 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.