New brittle­stars (Echinodermata: Ophiuroidea) from New Zealand waters Author Mcknight, Donald G. text Zootaxa 2003 352 1 36 journal article 51250 10.5281/zenodo.156750 db5a5512-bcdb-4bc0-8221-049102f18639 1175­5326 156750 Renetheo n. gen. Disc very small, skin­covered, sometimes with a few small spines centrally; radial shields absent. Arms 5–6, slender and long; scarcely tapering until near tip; oral shields present, more or less lateral, pointed proximally except madreporite which is enlarged and rounded; second oral tentacle­pore opens outside oral slit; genital slits short, very inconspicuous, between adoral shields and first lateral armplate at ventral disc margin. Genital scales absent. Dorsal surface of arm skin­covered and flat for about half of length; with vertebrae visible beneath the skin; beyond and starting abruptly are thin rounded­triangular dorsal armplates, slightly separated by the lateral plates. Ventral armplates present for basal 10– 12 arm segments only, the distalmost often in 2 pieces. Lateral armplates meet or almost meet on ventral midline, ventral plates, when present, lie distal to them; on dorsal surface they are widely separated proximally and do not meet until dorsal plates are present; they have a distinct spine­bearing ridge with 6–8 thorny, hyaline armspines, longest dorsally, uppermost often lying across dorsal surface, but not supporting the skin; lowest spine flattened, acting as tentacle­scale. Vertebrae zygospondylous. Type species : Renetheo felli n.sp. Etymology : The generic name commemorates two indefatigable workers in the Ophiuroidea, Rene Koehler and Theodor Mortensen. Remarks : This genus clearly differs from any other in the Ophiomyxidae ; the occurrence of the only distal dorsal armplates, while the ventral armplates are present proximally only, is quite unique; Astrogymnotes , another genus in the Ophiomyxidae with long arms and a very small disc, lacks dorsal armplates and has granules over the disc and arms. With a series of dorsal and ventral armplates, genital slits, absence of gonads along the arm and absence of radial intestinal diverticula this genus cannot be referred to the family Ophiocanopidae .