The deep sea synaptid Protankyra brychia (Echinodermata: Holothuroidea) and its near-surface dwelling planktotrophic larva, Auricularia nudibranchiata

Pacific and Atlantic Ocean material of the bathyal to abyssal synaptid holothurian genus Protankyra confirm that P. abyssicola (Theel) and P. pacifica (Ludwig) are subjective synonyms of P. brychia (Verrill 1885). This species is probably cosmopolitan in distribution at 869-4990 m. Post-larval juveniles from several localities in the Atlantic and Pacific Oceans retain wheel ossicles from pelagic planktotrophic larvae; the wheels are identical to those of the giant pelagic larva Auricularia nudibranchiata Chun 1896. We believe that Auricularia nudibranchiata is the larva of P. brychia.