Table 4 in Review of Ophioplinthaca Verrill, 1899 (Echinodermata, Ophiuroidea, Ophiacanthidae), description of new species in Ophioplinthaca and Ophiophthalmus, and new records from the Northwest Pacific and the South China Sea

Table 4. Tabular key to all species of the genus Ophiophthalmus. Abbreviations: ASE arm segment, DAP dorsal arm plate, DAS dorsal arm spines, LOP lateral oral papillae, RS radial shield, TS tentacle scale, VAP ventral arm plate, VAS ventral arm spines, VMT ventralmost papillae.
SpeciesNo. of arm spinesRadial shieldOral frameTentacle scaleDorsal arm plate (DAP) and Ventral arm plate (VAP)Arm spine shape and lengthDisc spine or granularReferencesOphiophthalmus cataleimmoidus (H. L. Clark, 1911)up to 7small, ovoid, naked, as long as wide, widely separated3-4 LOP; 1 VMT equal of sizeone, large, flat, rounded, and distinctly curved outward1stVAP rounded triangular shape, then wider than long, hexagonal or pentagonal, separated DAP wider than long, triangular shape with distal curve, first few DAP with single raw of rounded grain in distal margin, contiguous only in proximal halfsmooth, slender, tapering spine, next to uppermost DAS longest, 3 × ASE lengthmore or less sparsely with coarse, rounded granulesH. L. Clark (1911), Liao (2004)Ophiophthalmus hylacanthus (H. L. Clark, 1911)up to 8small, ovoid, naked, widely separated3 LOP; 1 VMT, LOP smaller than VMTone, large, flat, rounded, but become narrow and pointed along the armVAP wider than long, hexagonal or pentagonal, separated DAP wider than long, triangular shape with distal curve, first few DAP with rounded grain in distal margin, contiguous only at arm basesecond or third form upper DAS longest more than 2 × ASE length, uppermost DAS and lowermost VAS smooth, intermediate ones with slightly rough tipstout, pointed, rough spine, scattered coarse granules among spine near RSH. L. Clark (1911)Ophiophthalmus normani (Lyman, 1879)up to 4small, ovoid, naked, as long as wide, widely separated3 LOP, widely spaced, cylindrical, tapering, peg-like, 1 VMTone, large and oval1stVAP rounded triangular shape, then wider than long, separated DAPas wide as long, distal curve, 1-4 DAP with single raw of rounded grain in distal margin, contiguous only in proximal halfsmooth, slender, blunt, and tapering spine, lowest VAS ≈ 1 × ASE, upper DAS 1- 1½ × ASE lengthrounded granules or short stump, sparsely spread on the discLyman (1879), H. L. Clark (1911), Koehler (1922), Liao (2004)Ophiophthalmus relictus (Koehler, 1904)up to 6ovoid, naked, distal end well rounded, widely separated3-4 LOP, Conical to pointed tip, 1 VMTone, pointed1stVAP rounded triangular shape, then wider than long, hexagonal or pentagonal, separated DAP wider than long, triangular shape with distal curve, DAP with rounded grain in distal margin and surface, contiguous only in proximal halfshort, stout, longest one nearly 1 × ASE length, VAS quite rough near tipdense, smooth or sometime rough minute granulesKoehler (1904), H. L. Clark (1911)Ophiophthalmus serratus sp. nov.up to 5ovoid, naked, widely separated3-4 LOP, rugose, pointed tip, 1 VMTone, slightly elongated blunt tipped, as long asVAP1stVAP rounded triangular shape, then slightly pentagonal, separated DAP twice as wide as long, triangular shape with distal curve, first DAP has few rounded grains in distal margin (only 2 or 3 arms), contiguous only in arm base then separatedfinely Ophioplinthaca serratus, blunt tip; DAS ≈ 1½ -2 × ASE length, dorsalmost longest, next two similar in length, VAS shorter, 1- 1½ × ASE length, rough and shorter at distal end of the armdense, rounded to cylindrical stumps-like smooth granules, except radial shield and small area at center of discthis study