Who's who among baby brittle stars (Echinodermata: Ophiuroidea): Postmetamorphic development of some North Atlantic forms

Abstract

The ophiuroid skeleton continues to develop well beyond metamorphosis and small juveniles often lack many of the characters used to identify adult specimens. The ecological role of postmetamorphic stages is largely unknown mainly due to difficulties with their identification. Accurate descriptions of postlarvae and their development are therefore necessary to match them to their adult conspecifics. However, juveniles are known for less than 2% of the about 2000 extant species of ophiuroids. Consequently, the taxonomic value of juvenile characters is still poorly understood. In this study, the postlarval ontogeny of the non-brooding Ophioscolex glacialis, Ophioscolex purpureus, Ophiolimna bairdi, Ophiopleura borealis, Ophiura robusta, Amphiura chiajei, Ophiopus arcticus, Histampica duplicata, Ophiothrix fragilis, Ophiocomina nigra, and the brooding Ophiomitrella clavigera, Ophiacantha anomala and Amphiura borealis are described for the first time. The first complete description of the development of Amphiura filiformis is provided, for which previously only the development of the oral skeleton had been described. Previous descriptions of postlarvae of Ophiura ophiura, Ophiura albida and Asteronyx loveni are supplemented. © 2005 The Linnean Society of London.