Ophiodelos Koehler, 1930

Martynov, Alexander, 2010, Reassessment of the classification of the Ophiuroidea (Echinodermata), based on morphological characters. I. General character evaluation and delineation of the families Ophiomyxidae and Ophiacanthidae 2697, Zootaxa 2697, pp. 1-154 : 65-66

Genus Ophiodelos Koehler, 1930

Ophiodelos Koehler, 1930: 93–94

Type species: Ophiodelos insignis Koehler, 1930 , by monotypy

Diagnosis. This genus has a very peculiar external appearance, because of very short arms, which rapidly taper distalwards. The dorsal disk consists of numerous small disk scales covered with small granules, some of which extend onto the dorsal arm surface. A skin layer is not evident. The radial shields are very small, hardly conspicuous. The genital slits are conspicuous. The jaw bears several small square or rounded oral papillae. The teeth are spiniform and few in number. The adoral shield papillae do not differ from the other oral papillae. Judging from the spiniform teeth, the dental plate should have small rounded sockets. The oral (possibly triangular) and adoral shields concealed by skin. The adoral shields are considerably elongated. The dorsal and ventral arm plates are well developed. The dorsal arm plates are triangular, with a convex distal edge, contiguous. The ventral arm plates are contiguous, with a convex distal edge and straight proximal edge. The spines are flattened and ribbed. One long spiniform tentacle scale is placed on the lateral arm plate.

Remarks. The general shape of the genus Ophiodelos makes it a very aberrant ophiuroid, hardly comparable with any other ophiacanthid genus. There is only a single taxon of the class Ophiuroidea, which closely resembles Ophiodelos , the aberrant genus Ophiambix , which has been placed in three different families ( Paterson & Baker 1988). According to the latter study, this genus should be placed within the family Ophiuridae , however, the arm spine articulations of Ophiambix point to Ophiolepididae affinities ( Martynov 2010). Very short arms, rapidly tapering distally, very small disk covered with small granules continuing onto the dorsal arm plates, inconspicuous radial shields, strong flattened spines with ribs – all these features are shared by both genera Ophiodelos and Ophiambix . Ophidelos insignis differs considerably from described species of the genus Ophiambix ( Bartsch 1983; Paterson 1985; Paterson & Baker 1988), because of the presence of only a single long spiniform tentacle scale and the weak dorsal granular covering of the disk and arms. This does however not exclude the possibility that Ophiodelos insignis should be placed in Ophiambix . The holotype of Ophiodelos insignis was not examined; therefore a definite conclusion on its placement cannot be made now.