Taxonomy, biodiversity and biogeography of the brittle stars (Echinodermata: Ophiuroidea) of South Africa

The South African Ophiuroidea were last reviewed by Clark and Courtman-Stock in 1976. In the current investigation, the systematics of the group is thus revised in its entirety for the first time in 40 years. The data used originated from a number of sources. Existing data were sourced from i) published literature, ii) large expeditions or survey data, iii) South African institutional collections and iv) international museums. The majority of new records and data were sourced from previously unidentified specimens deposited in the collections of various South African and international museums and/or institutions, as well as from photographic records and some new, project-specific collecting. A review is presented of the history of ophiuroid taxonomy in South Africa highlighting the progression of research and of species discovery in the region since 1783. All new records of Ophiuroidea from South Africa since (and including) 1977 are documented, with each species account detailing key references, distribution, ecology and additional remarks. As a result, an additional 28 species are added to the known fauna of the mainland Exclusive Economic Zone of continental South Africa, raising the total known number of ophiuroid species in the region to 136. The genus Ophiocoma Agassiz (Echinodermata: Ophiuroidea: Ophiurida: Ophiocomidae) is reviewed and the number of species in South Africa increased from four to eight. All species are briefly discussed in terms of taxonomy, geographic distribution and ecology. Furthermore, the juveniles of O. brevipes, which were found on the ventral side of some adult Ophiocoma brevipes specimens, are described in detail. The distribution of the type material of O. scolopendrina has led to some confusion, and it is considered appropriate to establish a neotype from the original type locality (Mauritius). During this study, an ‘orphaned’ collection of echinoderms housed at the Durban Natural Science Museum, South Africa was rediscovered. The collection included holotypes of the South African endemic ophiuroid Asteroschema capensis Mortensen, 1925 [=Asteromorpha capensis (Mortensen, 1925) according to Okanishi et al., 2013], the South African endemic asteroid Anthenoides marleyi Mortensen, 1925, and Hacelia superba var. capensis Mortensen, 1925 which were considered lost. The collection was found to include both wet and dry specimens of extant Asteroidea, Ophiuroidea, Echinoidea and Holothuroidea. Furthermore, Plococidaris verticillata (Lamarck, 1816) was recorded as a new distribution record for South Africa. Details of these specimens are recorded and the first photographic record of the collection is provided. The genus Asteromorpha Lütken (Echinodermata: Ophiuroidea: Euryalidae: Euryalinae) is revised, and Asteroschema capensis being transferred to this genus as a new combination. Consequently, Asteromorpha now includes four species: A. capensis, A. koehleri, A. rousseaui, and A. tenax. All four species are redescribed and a taxonomic key to the species of the genus Asteromorpha is provided. An identification guide to the Ophiuroidea of South Africa, designed to be comprehensive, illustrated and easy to use for both naturalists and professional biologists, is included. Taxonomic terms, morphological characteristics and technical expressions are defined and described in detail with illustrations to clarify some terminology. The guide includes a taxonomic key to all 136 species, key references, distribution maps, diagnoses, scaled photographs (where possible), and a synthesis of known ecological and depth information.