Renetheo, Mcknight, Donald G., 2003

Mcknight, Donald G., 2003, New brittle­stars (Echinodermata: Ophiuroidea) from New Zealand waters, Zootaxa 352, pp. 1-36 : 6-7

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 .