Species;"No. of arm spines";"Radial shield";"Oral frame";"Tentacle scale";"Dorsal arm plate (DAP) and Ventral arm plate (VAP)";"Arm spine shape and length";"Disc spine or granular";References "Ophiophthalmus cataleimmoidus (H. L. Clark, 1911)";"up to 7";"small, ovoid, naked, as long as wide, widely separated";"3–4 LOP; 1 VMT equal of size";"one, large, flat, rounded, and distinctly curved outward";"1st VAP 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 half";"smooth, slender, tapering spine, next to uppermost DAS longest, 3 × ASE length";"more or less sparsely with coarse, rounded granules";"H. L. Clark (1911), Liao (2004)" "Ophiophthalmus hylacanthus (H. L. Clark, 1911)";"up to 8";"small, ovoid, naked, widely separated";"3 LOP; 1 VMT, LOP smaller than VMT";"one, large, flat, rounded, but become narrow and pointed along the arm";"VAP 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 base";"second or third form upper DAS longest more than 2 × ASE length, uppermost DAS and lowermost VAS smooth, intermediate ones with slightly rough tip";"stout, pointed, rough spine, scattered coarse granules among spine near RS";"H. L. Clark (1911)" "Ophiophthalmus normani (Lyman, 1879)";"up to 4";"small, ovoid, naked, as long as wide, widely separated";"3 LOP, widely spaced, cylindrical, tapering, peg-like, 1 VMT";"one, large and oval";"1st VAP rounded triangular shape, then wider than long, separated DAP as wide as long, distal curve, 1–4 DAP with single raw of rounded grain in distal margin, contiguous only in proximal half";"smooth, slender, blunt, and tapering spine, lowest VAS ≈ 1 × ASE, upper DAS 1–1½ × ASE length";"rounded granules or short stump, sparsely spread on the disc";"Lyman (1879), H. L. Clark (1911), Koehler (1922), Liao (2004)" "Ophiophthalmus relictus (Koehler, 1904)";"up to 6";"ovoid, naked, distal end well rounded, widely separated";"3–4 LOP, Conical to pointed tip, 1 VMT";"one, pointed";"1st VAP 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 half";"short, stout, longest one nearly 1 × ASE length, VAS quite rough near tip";"dense, smooth or sometime rough minute granules";"Koehler (1904), H. L. Clark (1911)" "Ophiophthalmus serratus sp. nov.";"up to 5";"ovoid, naked, widely separated";"3–4 LOP, rugose, pointed tip, 1 VMT";"one, slightly elongated blunt tipped, as long as VAP";"1st VAP 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 separated";"finely 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 arm";"dense, rounded to cylindrical stumps-like smooth granules, except radial shield and small area at center of disc";"this study"