Giving up on elaborate dermal ossicles: a new genus of ossicleless Apodida (Holothuroidea)

Abstract

In this paper we describe a new genus and a new species of Chiridotidae based on specimens collected in shallow water off the South-eastern Brazilian coast. Gymnopipina ikamiaba gen. nov. et sp. nov. is characterized by the complete absence of dermal ossicles in the body, and it differs from the other ossicleless apodids in the number of tentacles and of Polian vesicles, and in the morphology of the calcareous ring. Although not formally tested with a phylogenetic framework, apodids have apparently lost their dermal ossicles multiple times. If these reversions hold true, Gymnopipina gen. nov. represents the fourth independent loss of dermal ossicles in the class Holothuroidea. An identification key to the Brazilian apodid species is also provided.