ORDER CRYPTOPHIALIDA KOLBASOV, NEWMAN & HØEG, 2009

Diagnosis: Monophyletic group in molecular analyses. Females with bottle-like mantle; operculum with elongated neck; aperture small, crown-shaped opercular bars occupy the complete apertural length, lateral and reinforcing bars developed, long and thin; labrum elongated, tongue-like; mouth cirri rudimentary; thorax with one or two whip-like, long dorsal processes, sets of thoracic lappets with cuticular border; intestine with gizzard (gastric mill); caudal appendages absent. Dwarf males with elongated posterior end having circular cuticular ribs. Cypris larvae with rudimentary thorax and thoracopods. Boring aperture rounded.