DOI: 10.5281/zenodo.15138487
title: Table 2 in Order Euryalida (Echinodermata, Ophiuroidea), new species and new records from the South China Sea and the Northwest Pacific seamounts

description: Table 2. Tabular key to the species of Asteroschema and Ophiocreas. Abbreviations: ASS arm segment, ARS arm spine, GO granular ossicles, RS radial shield, CO conical ossicles, PO plate-like ossicles, TP terminal projection, GS genital slits.
SpeciesDisc diameter and arm lengthEpidermal ossicles on the discEpidermal ossicles on the armARS lengthARS shapeAS from segment 1st (2nd)ReferenceDorsalVentralDorsalVentralAsteroschema ajax A. H. Clark, 194913 mm and 300 mmfine GO; RS narrow, parallel, raised above the disc not meeting at centerfine GOwell-spaced annular bands when dried, covered with GOcovered with GO as dorsalunknownunknownunknownClark A. H. (1949)Asteroschema arenosum Lyman, 18788-9 mm and arm length unknown (arm width 4 mm)coarse GO, 5 grains in 1 mm; RS wide, not meeting at centercoarse GO but near mouth area scattered, jaw covered with GOcoarse GO but denser than on discas dorsalinner ≈ 2 × outerinner spine: cylindrical, slightly swollen, thorny dark tip2 (4)Lyman (1878, H. L. Clark (1941), Pawson et al. (2009)Asteroschema bidwillae McKnight, 20005 mm and 50 mm (6 arms)flat, small, very finely rugose GO, dense at center; RS and interradially (8-10 grains in 1 mm) but slightly spaced beside each RS; more or less extending to centervery small well-spaced GO, except on elongated oral platesflat, small, very finely rugose GO, slightly spaced toward distal end, almost absent near tip, lateral surface always spacedGO present on plates near arm base, then nakedinner> outer (inner 1 × ASE, outer 1/3 × ASE length)inner spine: slightly flattened, denticulate over most of length, and proximal margin beset with small curved spines2 (8-14)McKnight (2000), Mah et al. (2009), this studyouter spine: small and inconspicuous distally both spines flattened and pointed, but hooks absentAsteroschema brachiatum Lyman, 18796-11 mm and 270 mm (arm base width 3 mm)dense, uniform GO; RS elevated, extending nearly to centersimilar to dorsal, inconspicuous GO, which simulate oral papillaeclosely uniformly covered with GO; 6-9 grains in 1 mmas dorsalinner> outer (inner spine 2 mm)inner spine: rough, slightly club-shaped2 (4)Lyman (1879, 1882), H. L. Clark (1941)Asteroschema clavigerum Verrill, 18948-12 mm and arm length unknown (arm base width 3-3.5 mm)small, smooth GO, 6 grains in 1 mm; RS large, extending to center, GO larger than on disc.smooth skin lacking GO or minute, more spaced GOsmall, smooth GOonly base of arm covered with minute, more spaced GO, and rest of arm nakedinner> outerinner spine: large, long, elevated, and rough with spinules distally; somewhat swollen3-4 (4-5)Verrill (1894), Döderlein (1927)outer spine: smalldistally both spines small, slender, acute and nearly equalAsteroschema domogranulatum sp. nov.9 mm and 165 mmdense, large slightly domed GO, 4 or 5 grains in 1 mm; RS wide, parallel, raised above the disc close togetherlarge polygonal PO except distal half of jawlarge polygonal PO in proximal arm; then slightly separated, decreasing in size GOarm base concealed by polygonal PO; remainder nakedinner ≈ 2 × outerinner spine: pointed thorny tip to cylindrical, slightly club shaped, flattened thorny2 (19-22)This studyouter spine: small with thorny tipdistally both compound hook with 3-6 secondary teethAsteroschema edmondsoni A. H. Clark, 194913 mm and 290 mmGO & CO; dense GO on proximal half of RS, larger CO with TP on distal halfdense rounded GOdense PO, swollen in the middle with TP; TP absent in distal end of armsame as on ventral disc; but smallerunknownunknownunknownClark A. H. (1949)Asteroschema elongatum Koehler, 19147-11 mm and 300 mmstrongly excavated, GO rounded, unequal, slightly coarse near disc periphery; RS meeting at center, separated, GO larger and denser than on discminute GO, uniform, separated, slightly stronger near peripheryon first few segments GO like on RS then spaced, small, and uniformGO much smaller and uniform, rapidly becoming fewer and finally disappearing after 30-40 mm from arm baseinner> outerinner spine: cylindrical, strong, thinner at tip with TP2 (5)Koehler (1914), Döderlein (1930)outer spine: conical, pointed tipAsteroschema fastosum Koehler, 19046-13 mm and 180-300 mm (arm base width 5 mm)high, CO including RSsmall CO, more rounded, close-set at disc marginsmall CO, more close-set than on disc, 6 or 7 grains in 1 mmflattened COinner> outer (inner spine ≤ 4 mm)inner spine: bluntly conical at arm base, then strongly club-shaped with TP2 (4-5)Koehler (1904), Döderlein (1927, 1930), Guile (1981)outer spine: cylindrical, thorny tipdistally both spines compound hook with 2-4 secondary teethAsteroschema flosculus Alcock, 1894-GO & CO; scattered as uniform microscopic GOuniform microscopic GOGO & CO; scattered as uniform microscopic GOuniform microscopic GOlargeunknown3 (3)Alcock (1894)Asteroschema glaucum Matsumoto, 191511 mm and 100 mm (4 mm width in arm base)flat; coarser GO, 6 grains in 1 mm; RS mostly covered except distal endcoarser GO; near apex of jaw less GOcoarser GO, 6 grains in 1 mm, very stout at base, as high as wideas dorsalinner> outerinner spine: cylindrical, club-shaped, rough end2-3 (8)Matsumoto (1915)distally both spines compound hook with four curved secondary teethAsteroschema hemigymnum Matsumoto, 191510 mm and 100 mm (3 mm width in arm base)very fine, smooth, close-set GOventral: fine, rather sparse GO in skin, coarse, flat, smooth, pavement-like grains, corresponding to oral papillaevery fine, smooth, close-set GO; 5 grains in 1 mm; GO much finer distalwards and disappear at distal end.entirely naked; LAP and VAP visible through skininner> outer (outer spine ½ × ASE length)inner spine: cylindrical, club-shaped2 (5-6)Matsumoto (1915)outer spine: small, cylindrical, enclosed in skin, more or less rough tipdistally both spines compound hook with 3-6 secondary teethAsteroschema horridum Lyman, 187910-12.5 mm and 160-190 mmtumid polygonal PO; mostly tall CO with terminal projectionsPO & CO higher and thinner at disc peripheryPO, larger on arm base than on disc, 4 PO in 1 mm at arm base; weakly annulatedPO & CO lower and thinnerinner ≈ 2 × outerinner spine: cylindrical with TP, slightly swollen1 (1-6)Lyman (1879, 1882), Baker (1980), Mah et al. (2009), McKnight (2000)Asteroschema igloo Baker, 19805.7 mm and 68.4 mm (1: 12-disc diameter to arm length)rounded or polygonal domed GO, 4-6 grains in 1 mm length; RS short, obscured, distally visibleclosely packed rounded, domed GOdorsal & ventral: rounded or polygonal domed GO; 4-6 grains in 1 mm lengthas dorsalinner ≈ 2 × outer (inner spine 2/3 × arm width)inner spine: long, very fine, thorny blunt tip3: (8-10)Baker (1980), McKnight (2000)distally both spines compound hook with 3-6 secondary teethAsteroschema inoratum Koehler, 19066-10 mm and 70+ mmfine, contiguous GO (rounded or slightly conical); RS wider, extending to centerGO density similar to dorsal, slightly developed around GSfine, rounded or slightly conical, contiguous GOas dorsalinner ≈ 1½ × ASE lengthinner spine: slightly club-shaped, Swollen toward the end with conical point2 (5-7)Koehler (1906), Peterson (1985), Hansson (2001), Smirnov et al. (2014)outer spine: smooth, much smaller distally both spines small, but not transforming into a hookAsteroschema intectum Lyman, 18785-11.5 mm and 280 mm (arm width 3 mm)fine GO, 6-7 grains in 1 mm; RS long, meeting at center, GO fine than on disc, 8-9 grains in 1 mmfine GO except jawGO scattered, and smaller than on disc.lateral and ventral side naked or fewer GOinner> outerinner spine: blunt, spiniform, not club-shaped2 (3)Lyman (1878), H. L. Clark (1941)Asteroschema laeve (Lyman, 1872)8.5 mm and 85 mmflat; fine close-set GO, 7-8 grains in 1 mm; RS mostly covered with GO except distal endminute, close, smooth GO, fewer GO near apex of jawfine close-set GO, 7-8 grains in 1 mm, thin skin, faint brown markingas dorsalinner> outerinner spine: cylindrical, somewhat swollen, rough end2 (8)Lyman (1875, 1879), H. L. Clark (1941)distally both spines compound hook with 4 curved secondary teethAsteroschema lissum H. L. Clark, 19397.5 mm and 110 mmvery fine, small GO; 50-60 grains in 1 mm2, but noticeably smaller at center and proximal end of RS; RS separated, narrow, straight, parallel, not meeting at centernaked with thin skinfine GO similar on disc, laterally sparse, but continuous to base of ARS, distally sparse, and nakednaked with thin skininner ≈ 2-3 × outerinner spine: long, thick, thorny tip2 (9-11)H. L. Clark (1939) This studyAsteroschema migrator Koehler, 190411 mm and 200-300 mmsparse, domed CO with terminal projections, CO dense on RS & disc marginfew small COclose-set, small, tumid GOfew GO or COinner ≈ 2 × outerinner spine: cylindrical, swollen, TP outer spine: small, with pointed tip3 (6-8)Koehler (1904) Baker (1980) McKnight (2000)Asteroschema monobactrum H. L. Clark, 19178 mm and 80-90 mm (base arm width 2 mm)GO, flat, slightly raised above arm, near center 7 grains in 1 mm (50 mm2), but disc periphery 5-6 grains 1 mm (30 mm2)); RS completely covered but rounded ridges appeared when driedsimilar GO density as dorsalGO on arm base similar to disc, then separated, very minute, distally almost nakedGO, from middle slightly nakedinner ≈ 2 × outerunknown2 (11-16)H. L. Clark (1917)Asteroschema nuttingii Verrill, 18997 mm and 50 mmminute rough GO/CO; close-set on RSfew GO near GS; minute rough GO/COminute GO/CO, distinct distallyminute rough GO/COinner> outerinner spine: slender, tapering at arm base, then cylindrical, blunt, swollen distally, with TP1 (1-2)Verrill (1899)Asteroschema oligactes (Pallas, 1788)4-10 mm and 250 mm (length ≈ 17 × disc diameter)COCOCO; 4-5 CO in 1 mm on ventral arm baseas dorsalinner> outerunknownunknownPallas (1788), H. L. Clark (1941)Asteroschema rubrum Lyman, 187912 mm and 160 mmfine, close-set GO, 6-7 grains in 1 mm; RS faintly indicated as flat ridgesfine, close-set GOfine, close-set GO, 6-7 grains in 1 mmas dorsalinner spine maximum length 1.4 mminner spine: small spiniform at arm base, then cylindrical, swollen with TP2 (5-6)Lyman (1879, 1882), This studydistally both spines compound hook with secondary teethAsteroschema salix Lyman, 18795-8.5 mm and 55-85 mmflat, fine, close-set GO, 7-8 grains in 1 mm; RS mostly covered with GO except distal endfine, minute, close-set GO, less GO near apex of jawfine, close-set GO, 7-8 grains in 1 mm, thin skinas dorsalinner> outerinner spine: cylindrical, somewhat swollen, rough end2-3 (11-12)Lyman (1879), Baker (1980), McKnight (2000), Olbers et al. (2015), This studydistally both spines compound hook with 4 curved secondary teethAsteroschema sampadae Parameswaran & Jaleel, 201218 mm and 380-450 mmspaced CO with terminal projections; RS covered with CO, extending to centerminute, spaced GOspaced CO with terminal projections, denser at arm baseminute, spaced GOinner ≈ 2 × outer, inner spine ≤ 2 × ASE (5 mm)inner spine: bluntly conical at arm base; then cylindrical, with TP at inner edge2 (4)Parameswaran and Jaleel (2012)Asteroschema shenhaiyongshii sp. nov.10 mm and 220 mm (arm base width 3.4 mm)small, finely rugose, rounded GO, similar in size, 8-9 grains in 1 mm; RS wide, parallel, close together, not meeting at center, distal end of RS raised above disc, swollen at centerGO similar on dorsal, spearhead-shaped teeth. GS narrow concealed with GOdorsal: dense GO similar to disc; 8-9 grains in 1 mm; distally GO less rounded but denseless rounded and more polygonal GO, concealing only proximal half of arm, in middle to distal ventral arm surface concealed with widely separated GO decreasing in size to completely nakedinner> outer (inner spine 2.2 mm long)inner spine: cylindrical, thorny tip to less club-shaped with small sharp thorns on more than half its length2 (9-11)This studyouter spine: small in size with thorny tip similar to inner spinedistally both spines similar in size, compound hook with 4 or 5 secondary teethAsteroschema subfastostum Döderlein, 19308 mm and 9 × disc diameterpointed CO, blunt at disc margin, 4-5 grains in 1 mmsmooth hemispherical GOpointed COsmooth hemispherical GOinner> outerunknownunknownDöderlein (1930)Asteroschema sublaeve Lütken & Mortensen, 188912 mm and 300 mm (arm base width 5 mm)round, rugose GO variable size; RS covered with larger GO than on the discsmooth, small GO, few GO lateral at jawround, rugose GO variable size, smaller at lateral side, larger on dorsal surfacenakedinner ≈ 2 × outer; in middle (inner ≈ 4 × outer)inner spine: elongated, club shaped, enclosed with thick skin2-3 (3-4)Lütken and Mortensen (1889)Asteroschema sulcatum Ljungman, 18725 mm and arm length unknowndense, small GO (9-15 grains in 1 mm); RS narrow, not meeting at centerdense, small GO, teeth rounded or distally lobeddense, small GOas dorsalinner> outerinner spine: strongly thorny tip, swollen, bent club shaped(3-12)Ljungman (1872), Lyman (1875)Asteroschema tenue Lyman, 18756 mm and 200 mm (arm base width 1.5 mm)closely, smooth GO (8-9 grains in 1 mm); RS narrow, meeting at center and GO little coarsercoarser GO; large GO in jawslender arms; similar to dorsal disc, distally GO much finer and more scatteredas dorsalinner> outer, inner spine 1 mm long in middle halfinner spine: spiniform at arm base, then large, fine thorny, club-shaped1 (3)Lyman (1875), H. L. Clark (1915)Asteroschema tubiferum Matsumoto, 191114-16 mm and 230-300 mmclosely and evenly, small rounded or polygonal GO; RS narrow, not meeting at center but convergententirely covered with dense GO, slightly large, rounded GO corresponding to oral papillaeGO similar to disc, 4-5 grains in 1 mmdistally GO smaller, widely spaced on ventral sideinner> outerinner spine: cylindrical, initially tapering to a blunt, thorny tip, middle club-shaped with small sharp thorns, first 10-12 covered by sheath2 (7)Matsumoto (1911, 1915), Baker (1980), McKnight (2000), This studyouter spine: small, pointed tipdistally both spines compound hook with secondary teethAsteroschema tumidum Lyman, 18798-13 mm and 120-180 mmdense, rounded GO proximally, CO at disc margin regularly spaced pointed; RS covered with CO, extending to centersimilar to dorsal but lowerregularly spaced pointed, CO; 4 grains in 1 mm, rarely touching each otheras dorsalinner> outer, inner spine ≤2 mm longinner spine: rough, slightly club-shaped2 (3)Lyman (1879, 1882) Koehler (1904)Asteroschema vicinum Koehler, 19077 mm and 93 mmfine GOfine GO, more than 9 grains in 1 mm, GO much larger around jawfine GOas dorsal½ × ASE lengthboth sub-equal, fairly short, same morphology along the arm- (2)Koehler (1907)Asteroschema wrighti McKnight, 20006.5 mm and at least 6 × disc diameterfine and uniform GO, 8-10 grains in 1 mm; RS elongated, meeting at centerthin smooth skin, occasional small GO; relatively large irregular PO in GSfine and uniform GO; 8-0 grains in 1 mm; extending to lateral surfaceoccasional small GO, thin and smooth skininner> outer, inner arm spine up to 2 × ASE lengthinner spine: long, finely thorny, slightly club-shaped2(5-6)McKnight (2000)outer spine: relatively small and smoothdistally both spines compound hook with secondary teethAsteroschema yaeyamense Murakami, 19447 mm and 150 mmdense, coarse COrounded GOregularly spaced CO, distally swollen GOas dorsalinner> outerinner spine: long, cylindrical with TP2 (3-6)Murakami (1944), Liao (2004)Ophiocreas ambonesicum Döderlein, 192727-30 mm and 350-390 mmcoarse, thick, naked skin (when dry widely separated GO visible); RS narrow, not meeting at centeras dorsalnaked skin, when dry widely separated GO visible), annular bandnaked skin, when dry widely separated GO visible)inner ≈ 3 × outer; in middle 2 × ASS lengthinner spine: elongated, thick, enclosed with thick skin, cylindrical, club-shaped2 (8-12)Döderlein (1927)outer spine: cylindrical, pointed tipdistally both spines compound hook with 2-3 secondary teethOphiocreas carnosus Lyman, 187915 mm and 200 mm (arm base width 7 mm)thick, soft wrinkled skin; RS rounded distal end, narrow, meeting at disc centeras dorsalsmooth, soft wrinkled skinas dorsalinner ≈ outer, inner ≈ 3 mm longinner spine: short, enclosed by thick skin, cylindrical, thorny tip2 (6)Lyman (1879)outer spine: cylindrical, thorny tipOphiocreas caudatus Lyman, 187922-25 mm and 300-420 mm (arm base width 5.5-7.5 mm)covered with thick skin, when dry micro-GO visible; RS narrow, raised above the disc, meeting at centeras dorsalcovered by thick skin, when dry micro-GO visible at arm base, annular band.as dorsalinner 3 mm longer in middleinner spine: elongated, enclosed by skin, stout, thorny tip2 (10-13)Lyman (1879, 1882), Matsumoto (1917), Döderlein (1911), H. L. Clark (1949)outer spine: short, peg-likeOphiocreas oedipus Lyman, 18795-12 mm and 70-250 mm (arm base width 3.5 mm)thin skin with small, fine GO; RS narrow, closer together, extending to disc centersmall, closely set, rounded GO or naked, GS widethin skin with fine GO, first 5-8 ASS swollenas dorsalinner 1 × ASS length, outer ½ × ASS lengthinner spine: slender, elongated, enclosed by skin, blunt, thorny tip2 (6-9)Koehler (1904, 1909), Lyman (1879, 1882), H. L. Clark (1915), Baker (1980), Peterson (1985), McKnight (2000)outer spine: short, cylindrical, pointeddistally both spines compound hook with 6 secondary teethOphiocreas gilolense (Döderlein, 1927)22 mm and 290 mm (arm base width 9 mm)naked skin; RS meeting at centeras dorsalnaked skin, annular bandas dorsalinner ≈ 2 × outer; in middle 2 × ASS lengthinner spine: elongated, slender, cylindrical2 (3-4)Döderlein (1927)outer spine: cylindrical, pointed tipOphiocreas glutinosum (Döderlein, 1911)17 mm and unknown (arm base height 9 mm)dense small GO (10 grains in 1 mm); RS large (nearly covering whole disc), long, close to each other, meeting at centeras dorsalthick arms, thick skin covers arm plates completely, proximally dense small GO (10 grains in 1 mm), distally separated,as dorsalinner 1½ × ASS length, outer ≈ 1/3 × innerinner spine: slender, elongated, swollen thorny tip2 (6-7)Döderlein (1911)outer spine: smalldistally both spines compound hook with 2-3 secondary teethOphiocreas japonicus Koehler, 19074-33 and 210-655 mm (arm base width 7 mm)smooth, thin, small specimen with dense GO coverage (4 mm disc diameter); RS thick, raised above the disc, meeting at disc centeras dorsalsmooth, thin, naked skin, annular, (small specimen with dense GO coverage (4 mm disc diameter)somewhat fewer scattered GOinner ≤6 mm, 3 × ASS length; outer 1 × ASS lengthinner spine: elongated, thick base, cylindrical, thorny tip2 (3-12)Koehler (1907), Döderlein (1911), Matsumoto (1917), McKnight (2000)outer spine: cylindrical, pointed tipdistally both spines compound hook with 2-3 secondary teethOphiocreas lumbricus Lyman, 18694.5-17 mm and 50-240 mm (arm base width 2.5 mm)covered by separated micro-thorny GO; RS meeting at centeras dorsalcovered by separated micro-thorny GO annular bandas dorsalinner ≤ 1½ -2 × ASS length outer 1 × ASS lengthinner spine: cylindrical, enclosed by skin, blunt, rough surface, thorny tip2 (4)Lyman (1869)outer spine: cylindrical, enclosed with skin, blunt, rough surface, thorny tipOphiocreas mindorense (Döderlein, 1927)12-23 mm and 160-480 mm (arm base width 3-5.5 mm)smooth, dense GO (8 grains in 1 mm); RS narrow, closer together, extending to disc centeras dorsalsimilar to disc, smooth, dense GO (8 grains in 1 mm); GO absent on ventral side of younger specimensas dorsalinner 3-5.5 mm, in middle 2½ -3 × ASS length; outer 1 × ASS lengthinner spine: slender, elongated, swollen thorny tip2 (8-11)Döderlein (1927)outer spine: thick arm base with pointed tipOphiocreas mortenseni Koehler, 19307.5-25 mm and 110-400+ mm (arm base height 6 mm)covered by thick, wrinkled, or folded skin; RS narrow, extending to disc centercovered by plate-like ossiclesskin thicker than dorsal, mostly thickened near arm spines, archedas dorsalinner 1 × ASS length; outer 2/3 × innerinner spine: slightly flattened, rough in upper half, thorny tip2 (4-7)Koehler (1930), McKnight (2000)outer spine: short, cylindrical, thorny pointeddistally both spines compound hook with 3 or 4 secondary teethOphiocreas sibogae Koehler, 190414-28 mm and 300-350 mm (disc diameter × 30) (arm base width 5 mm)naked skin; RS narrow, parallel, not meeting at centeras dorsalnaked skin, annular bandas dorsalinner ≈ 2 × outer, in middle 2 × ASS lengthinner spine: elongated, slender, cylindrical, club-shaped, finely rugose2 (3-11)Koehler 1904, H.L. Clark 1916b, Mortensen 1924, Döderlein 1927, Baker 1980, McKnight (2000)outer spine: cylindrical, pointed tipdistally both spines compound hook with 2-4 secondary teethOphiocreas spinulosus Lyman, 18838-17 mm and 60-550 mm (arm base width 3 mm)naked skin; RS strongly marked ridges with short, stout blunt spines, meeting at centeras dorsalhigher than wide, naked skin, annular band blunt spine at each pair of ASSas dorsalinner ≈ 2 mm, equal in size in proximal armsinner spine: short, blunt, rough surface, cylindrical2 (3-4)Lyman (1883), H. L. Clark (1915, 1941)outer spine: cylindrical, pointed tip, distally slenderdistally both spines compound hook with 2 secondary teethOphiocreas willsi McKnight, 200016 mm and 380 mmcovered by thick, wrinkled, or folded skin; RS narrow, extending to disc center, dense small GO cover in the centercovered by well separated small GO.granulation similar to the disc, extending to the lateral arm, GO coverage dense proximally, but scattered distallyfirst 3-5 ASS with few GO, then nakedinner 1½ × ASS, outer shorter than ASSinner spine: slightly flattened, enclosed by skin, rough, blunt tip2 (2-3)McKnight (2000)outer spine: short, cylindrical, thorny pointeddistally both spines compound hook with 3 or 4 secondary teeth
description: Published as part of Nethupul, Hasitha, Stoehr, Sabine & Zhang, Haibin, 2022, Order Euryalida (Echinodermata, Ophiuroidea), new species and new records from the South China Sea and the Northwest Pacific seamounts, pp. 161 in ZooKeys 1090 on page 161, DOI: 10.3897/zookeys.1090.76292