Table 3 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 3. Tabular key to all species of the genus Ophioplinthaca. Abbreviations: ASE arm segment, ASS Adoral shield spine, DAP dorsal arm plate, DAS dorsal arm spines, L length, LOP lateral oral papillae, VAP ventral arm plate, VAS ventral arm spines, VMT ventralmost tooth, W width.
SpeciesNo. of arm spinesRadial shieldsOral frameTentacle scaleDorsal arm plate (DAP), and ventral arm plate (VAP)Arm spine shape and lengthDisc spinesReferencesOphioplinthaca abyssalis Cherbonnier & Sibuet, 1972up to 7separated proximally but connected at distal ends4-5 LOP, spiniform, 1 VMT1st pore 2, then 1, elongated, bluntVAP-separated, DAP 1-3 have few spines and contiguous then separatedthorny surfacelong, conicalCherbonnier and Sibuet (1972)Ophioplinthaca amezianeae O’Hara & Stöhr, 2006up to 10separated, L = 2Wup to 4-5 LOP, spiniform, 1 VMT1st pore 2-3, 2nd pore 1-2, then 1, spiniform with rounded base, tapering sharply or tip covered in irregular thornsseparatedcovered with conspicuous thornslong, rounded base, with spinelets on lateral surfaceO’Hara and Stöhr (2006), this studyOphioplinthaca athena A.H. Clark, 1949up to 5separated proximally, connected at distal ends, L = 4W4 LOP, pointed, flattened, larger, equal in size, 1 VMT1st pore 2, then 1, oval, pointed, beyond 3rd pore slender spiniformVAP on 1stASE contiguous with next, then separated, DAP contiguous (terminal portion slightly separated)1stDAS smooth, 2 × ASE length; 2ndDAS, 4 × ASE length; shorter thorny VASelongated with thorny tip, at periphery with smooth tipA. H. Clark (1949), this studyOphioplinthaca brachispina sp. nov.up to 5separated by large single disc scale or connect at distal ends4 LOP, pointed, distal one with wider flat edge, 1 VMT, ASS covered by cluster of granules1st pore 2, half as long asVAP, terminally spiniferous, oval on base of arm, then slightly pointed along armDAP and VAP separated, thorny surfaceDAS with distal lateral thorns; VAS ≈ 1-2 × ASE length, pointed, thorny, rugosebifid or thorny pointed tip, cylindricalthis studyOphioplinthaca bythiaspis (H. L. Clark, 1911)up to 6separated, L = 4W4-5 LOP, equal in height, distally slightly wider, 1 VMToval to bottle-shaped, as long asVAPVAP separated beyond 3 ASEDAS smooth, VAS with thorny surfaceconical or more rounded with thorns at tipH. L. Clark (1911, 1915), O’Hara and Stöhr (2006)Ophioplinthaca carduus (Lyman, 1878)up to 6separated4-5 LOP, first 3-4 conical, blunt tip, distalwards flat, spearhead-shaped, small, pointed, 1 VMT, curved adoral shieldstrongly thorny, after 1st pore, with 1 or 2 lateral thornsVAP separated, DAP on 1-3 × ASE contiguous, then separatedstout, cylindrical, glassy, blunt, very thornyshort, stout stump with thorny tipLyman (1878)Ophioplinthaca chelys (C. W. Thomson, 1877)up to 6separated, deeply sunken5 LOP, first 3-4 conical, blunt tip, 1 VMTlarge and flatVAP and DAP separatedcylindrical, glassy, blunt, very thornycylindrical, thorny or smooth, thorny tip, spines dense in disc center.C. W. Thomson (1877)Ophioplinthaca citata Koehler, 1904up to 9separated L = 3-4W3-4 LOP, blunt, distal one has wider flat edge, 1 VMToval to ellipticalDAP contiguous, except first few ASE, VAP contiguousDAS ≈ 4 × ASE length, VAS short, thorny, hollowcylindrical, terminal crown of thornsKoehler (1904), O’Hara and Stöhr (2006)Ophioplinthaca clothilde A.H. Clark, 1949up to 7 at arm base then 5contiguous, ovoid, about half as long as broad4 LOP, pointed, flattened, large, 1 VMT of equal size1st pore 2, then 1, leaf-like to narrow, sharply pointed with numerous spinelets at tipVAP separated after 2 ASE, DAP separatedDAS ≈ 4 × ASE length, DAS and VAS with thorny surface, DAS longestin disc center cylindrical base ending in 2-3 sub-crowns, at periphery short, stout with irregular crown of a dozen or more thornsA. H. Clark (1949)Ophioplinthaca codonomorpha (H. L. Clark, 1911)up to 8widely separated, small, convex proximally, as wide as long3 LOP, 1 VMT1st pore 2, oval, conspicuously large, then oval with pointed tipVAP at 1st to 2ndASE contiguous then separated, DAP barely contiguous1-3 DAS smooth or thorny; VAS also smoothminute rough granulesH. L. Clark (1911)Ophioplinthaca crassa H. L. Clark, 1939basally 4 then up to 5 or 7distally connected, small, as wide as long, convex proximally3 LOP, narrow, elongated, pointed, distalwards short and wide, 1 large VMT1st pore 2-3, blunt, 1mm long and wide, very thick, somewhat triangular, then less stout, slender pointedVAP, DAP in first 1-2 ASE contiguous, then separatedshort, stout, but fragile, thorny spines, DAS ≈ 2 × ASE lengthlow cylindrical tubeH. L. Clark (1939)Ophioplinthaca defensor Koehler, 1930up to 7 at arm baseseparated proximally, connected distally4 LOP, 1 VMT1st pore 1, long, and leaf-like then narrower with pointed tipDAP and VAP contiguousthorny surface, conspicuous thorns on DAS; DAS ≈ 3 × ASE, VAS ≈ 1 × ASE lengthcylindrical with thorn at tipKoehler (1930), Na et al. (2021), this studyOphioplinthaca dipsacos (Lyman, 1878)up to 6separated proximally, connected distally4-5 LOP, pointed, flattened, ill-defined distalwards, 1 VMTlarge, pointed with 1 or 2 microscopic thornsVAP and DAP separatedlong, slender, DAS 5-7 × ASE length, with conspicuous thorns, VAS 1½ -2 × ASE length with thorny surfaceshort, stout, with thorny tip, at periphery smoothLyman (1878)Ophioplinthaca globata Koehler, 1922up to 6separated proximally, connected distally3-4 LOP, bunt, distal one has wider flat edge, 1 VMT, ASS covered by small granules1st pore 2-3, as long asVAP, terminally spiniferous in larger specimenDAP and VAP separatedthorny surfacecylindrical, bifid or tip mostly with 3 thornsKoehler (1922, 1930), O’Hara and Stöhr (2006)Ophioplinthaca grandisquama Chen, Na, & Zhang, 2021aup to 7contiguous, L = 1.5Wup to 3-4 LOP, spiniform, 1 or 2 VMT1st pore 1-2, only 1 in following ASE, long, thorny with thick base, tapering into blunt pointDAP contiguous, VAP separatedDAS thin with distal lateral thorns, up to 3 × ASE length; VAS short, blunt, and finely rugosestout, tall, bearing numerous distinct thorns laterally or at tip, some bifurcated into two prongs with thorny tipsChen et al. (2021a)Ophioplinthaca grenadensis John and A. M. Clark, 1954up to 5separated oval proximallyup to 5 LOP, spiniform, 1 VMTleaf-like, then slightly elongated with pointed tip along armDAP in first 1-2 ASE contiguous, then separated, VAP separatedflattened, covered by glassy spineslong, thick spinelets with rough thorny lateral surface in disc center, at periphery shorterJohn and A. M. Clark (1954)Ophioplinthaca hastata Koehler, 1922up to 7contiguous, L = 1.5W4-5 LOP, spiniform to club-shaped, distal ones largest, sometimes small granules present on distal edge of jaw, 1 VMT, 1 or 2 ASS1st pore 2, then 1, clavate, terminally spiniferous, longer than VAPseparatedsmooth, DAS ≈ 3 × ASE lengthnumerous thorns at cylindrical tipKoehler (1922), O’Hara and Stöhr (2006)Ophioplinthaca incisa (Lyman, 1883)up to 5small, separated proximally, connected distally4-5 LOP, spiniform., distal ones wide, flat, 1 VMT, 1 or 2 ASS1st pore 3, then 1VAP separatedsmooth, DAS ≈ 3 × ASE, VAS ≈ 1 × ASE lengthcylindrical with thorny tip or thorny surface laterally, at disc periphery smoothLyman (1883)Ophioplinthaca laudator Koehler, 1930up to 7small, separated proximally, connected distally4 LOP, sometimes irregularly arranged, elongated, pointed but distalmost one flat and wide, 1 VMT-VAP separated beyond 2ndASE, DAP separatedDAS thorny, VAS smooth, DAS ≈ 2 × ASE, VAS ≈ 1½ -2 × ASE lengthcylindrical with 2-3 thorns at tip or lateral thorns, at disc periphery smooth, conicalKoehler (1930)Ophioplinthaca lithosora (H. L. Clark, 1911)up to 6 or 7long, narrow, separated10-15 LOP including small granules at distal edge of jaw1st pore 3, 2nd pore 2, then one, large, pointed tipVAP separated, tetragonalfirst 1-2 DAS, smooth, 3 × ASE length, with thorny tip, 3 thorny VAScylindrical, bifid or mostly with 3 thorns at tip or with lateral thornsH. L. Clark (1911), this studyOphioplinthaca manillae Guille, 1981up to 6as wide as long, contiguous3 LOP, 1 VMT, rough edges, large, pointed, small granules at distal edge of jawoval, large, rough edgesDAP on first 1-2 ASE contiguous, then separated, VAP separatedDAS ≈ 3 × ASE, VAS ≈ 1 × ASE length, thornybifid or mostly with 3 divided thorns at tip, central spines longer than peripheral onesGuille (1981)Ophioplinthaca miranda Koehler, 1904up to 5 or 6separated proximally, connected distally3 LOP, 1 large VMTtriangularDAP and VAP contiguousboth DAS and VAS small, thorny, rugose and same lengthcylindrical with thorny circular tipKoehler (1904)Ophioplinthaca monitor Koehler, 1930up to 7 or 8separated4 LOP, 1 VMT, distalmost one smaller1st pore 2, then 1, oval to rounded proximally and pointed distallyDAP on first 2 ASE contiguous, then separated, fan-shapedDAS with conspicuously sparse thorny surface, VAS thornygranules with thorny tipKoehler (1930), O’Hara and Stöhr (2006)Ophioplinthaca papillosa H. L. Clark, 1939up to 7separated, narrow3-4 LOP, narrow, subequal, long, pointed, 1 VMTflat, moderately, large, pointedseparatedrough surface, DAS ≈ 3 × ASE, VAS ≈ 1 × ASE lengthin disc center with long tip dividing into 2-3 thorns, at periphery with spinous tipH. L. Clark (1939)Ophioplinthaca plicata (Lyman, 1878)up to 8contiguous, L = 2-2.5W3-5 LOP, 1-3 VMT, spiniform1st pore 2-3, curved inward, pointed round tipDAP contiguous, VAP separatedthorny surfaceconical, cylindrical, finely rugose or rarely with few longer thornsLyman (1878, 1882), Koehler (1904), O’Hara and Stöhr (2006)Ophioplinthaca pulchra Koehler, 1904up to 7separated proximally, connected distally4 LOP, 1 VMTleaf-likefirst two VAP contiguous, then separated, DAP contiguousthorny, rugose surface, uppermost DAS longestcylindrical with thorny tip in center, at periphery smaller and conicalKoehler (1904, 1922), O’Hara and Stöhr (2006)Ophioplinthaca rudis (Koehler, 1897)up to 5completely separated or distally connected5-6 LOP, spiniform, 1 VMTleaf-likeDAP contiguous or separated, VAP widely separatedfinely thornylong spines with smooth surfaceKoehler (1897), O’Hara and Stöhr (2006)Ophioplinthaca sarsii (Lyman, 1878)up to 8separated3 LOP small, pointed, 1 VMTflat, tapering, jaggedDAP, VAP separatedstout, cylindrical, glassy, blunt, very thornysmooth cylindricalLyman (1878)Ophioplinthaca semele (A.H. Clark, 1949)up to 7separated proximally, connected in distally, L ≈ 2½ -3W5 LOP, pointed, flatted, ill-defined, 1 VMT1st pore 3 or rarely 5, 2nd pore 2-3, 3rd pore 2, then one, large, pointed tipVAP in first 1-2 ASE contiguous, then separated, DAP separatedlong, slender, DAS with conspicuous thorns, VAS thorny surfaceshort, stout, with thorny tip, or 3 thorns, at periphery smooth spines without thornsA. H. Clark (1949), Chen et al. (2021a), this studyOphioplinthaca sexradia Mortensen, 1933up to 4separated proximally, connected distally3 LOP, 1 VMTsmall, leaf-likeseparated, smallsmall, thick baseirregular scales with conical tuberclesMortensen (1933)Ophioplinthaca spinissima H. L. Clark, 1900up to 9separated proximally, connected in distally, longer than wideup to 5-7 LOP, spiniform, 1VMT1st pore one or divided into two, then more pointed distalwards along armDAP widely separatedthorny surfacespine with thorny tip, or 3 thorns, at periphery smooth spines without thorns, tip relatively flat with thornsH. L. Clark (1900)Ophioplinthaca sp.up to 6contiguous, distally convex, proximally triangular L = 2W4-5 LOP, pointed, elongated, slightly flattened distal end, 1 VMT large, slightly longer than LOP1st pore 1-2, then 1, leaf-like, but along arm narrower, thorny, pointed; as long asVAPboth VAP and DAP widely separatedDAS has conspicuous lateral thorns; VAS with thorny surfacedisc center: conical or short cylindrical spines, when cylindrical with two sub-thorns; at periphery smooth, conical or short, cylindrical, finely rugose to smooththis studyOphioplinthaca tylota H. L. Clark, 1939up to 6separated proximally, connected distally4 LOP, narrow, equal, long, pointed, 1 VMTvery thick, heavy, smooth but increasingly flatter along arm, smaller, very thornyfirst and second DAP contiguous, then separated, VAP separatedthorny spine, DAS with conspicuous thorns, DAS ≈ 3 × ASE, VAS ≈ 1 × ASE lengthsmooth, rounded spineH. L. Clark (1939)Ophioplinthaca webri (Koehler, 1904)up to 7separated proximally, connected distally4 LOP, narrow, equal, long, pointed, 1 large VMT1st pore 2-3, then 1, elongatedDAP and VAP contiguous--Koehler (1904)