Early juvenile development of deep-sea asteroids of the NE Atlantic Ocean, with notes on juvenile bathymetric distributions

The postmetamorphic ontogenesis of 11 deep‐sea asteroid species is described. Juvenile bathymetric distributions are compared to adults. The deep‐sea juvenile asteroids of the NE Atlantic could be distinguished to species level from a very early stage of development. In all species, except Porcellanaster ceruleus and Plinthaster dentatus, the arms grow faster than the body. In Porcellanaster ceruleus and Plinthaster dentatus, early growth is nearly isometric. In the appearance of the epiproctal cone, the change in form of the furrow and apical spines, the early development of the cribriform organ adjacent to the madreporite and the appearance of sediment in the stomach indicate that Porcellanaster ceruleus is likely to undergo a shift in habitat and diet during the juvenile phase. Porcellanaster ceruleus is probably a predator on meiofauna and small macrofauna during the early stages of life, changing to a burrowing lifestyle ingesting sediment particles. Juvenile sea stars showed wider bathymetric distributions than their adult counterparts, suggesting that events occurring during the early stages of life are important for the maintenance of the local population structure and diversity in the deep NE Atlantic.