Two new species of brittle stars (Echinodermata: Ophiuroidea), living epizoic on a stalked crinoid

Brittle star species with epizoic life-style are found in at least a dozen families and on a wide variety of host animals (Cnidaria, Porifera, Mollusca, other Echinodermata). An overview of epizoic brittle star species is provided. This study is the first account of brittle stars living epizoic on the crinoid Neogymnocrinus richeri. Two species were described as new to science, for one of them, a new genus, Warenophis gen. nov., was erected. “Ophiomitrella” thuyi sp. nov. is tentatively placed in the genus Ophiomitrella, because the genus is polyphyletic and its type species was here found not to concur with the generic characters. All species of Ophiomitrella and Ophiosemnotes were analysed, key characters are listed, and the taxonomic status of these genera is discussed. Warenophis andersi gen. et sp. nov. possesses an unusual combination of features that doesn’t match any known genus, such as flat, serrated arm spines, large disc plates without granules or spines, arm spine articular structures with tongue-like extension, and it could not yet be placed in a family. Based on lateral arm plate characters, it has affinities with the Ophiacanthidae and Ophiotomidae.