Table 2 in Two new species of brittle stars (Echinodermata: Ophiuroidea), living epizoic on a stalked crinoid

Table 2 (continued on next two pages). Key characters of all species currently placed in the genera Ophiomitrella Verrill, 1899 and Ophiosemnotes Matsumoto, 1917, compiled from original descriptions, examinations of type specimens or photos of type material, and Paterson (1985). Abbreviations: AS = adoral shield; DD = disc diameter; OS = oral shield. Generic type species indicated by asterisk. SpeciesDD (mm)Disc spinesRadial shieldsOral shieldsAdoral shieldsGroup A: disc spines low, more or less spherical, or absentOphiomitrella americana Koehler, 19146.5small round, with thorny tipssmall, 1/₈ of dd, round, widely separatedrhombic, proximally acute, ~2× as wide as long, larger than ASnarrow crescent, proximal to OSOphiomitrella araucana Castillo-Alárcon, 19689small granules1/6 of dd, triangular, distally connectedrhombic, larger than ASnarrow crescent, proximal to OSOphiosemnotes brevispina (H.L. Clark, 1911)8none~1/6 of dd, rounded, widely separatedrhombic to pentagonaltrapezoidOphiomitrella cordifera (Koehler, 1896)4few, low, globular, short peduncle1/4 of dd, oval to triangular, distally connectedrhombic, proximally acute, larger than AScrescent, extend barely around OSOphiosemnotes diaphora (H.L. Clark, 1911)11round granules1/4 of dd, oval, widely separatedpentagonal, smaller than AStrapezoid, proximal to OSOphiomitrella globulifera (Koehler, 1896)11large, globular1/5 of dd, oval, widely separatedpentagonal to rhombic, large, distal projectionlarge, trapezoid, curved, proximal to OSOphiomitrella granulosa (Lyman, 1878)9dense, small granulessmall, distally connectedrounded triangular, smaller than ASlarge, trapezoid, proximal to OSOphiomitrella mensa O’Hara & Stöhr, 200610capitate stumps1/4 of dd, triangular, contiguoussmall, wider than long, pentagonaltrapezoid, larger than OS, proximal to OSOphiomitrella nudextrema (H.L. Clark, 1939)3trifid stumps1/6 of dd, triangulardiamond-shapedtrapezoid, largeOphiomitrella parviglobosa O’Hara & Stöhr, 20064spherical granules1/9 of dd, triangular to circularrhombiccrescent, proximal to OSOphiomitrella suspectus (Koehler, 1922)8dense, club-shaped, pediculate globules1/5 of dd, triangular, connectedrhombictrapezoid, large, proximal to OSOphiomitrella tenuis (Koehler, 1904)5–6dense, small, thorny, elongated granules1/6 of dd, triangular, separatedrounded rhombic, larger than AScrescent to trapezoid, proximal to OSOphiomitrella thuyi sp. nov.4.2smooth, spherical granules, variable size1/4 of dd, rounded triangular, separatedrounded triangular, small distal lobe, smaller than AStrapezoid, proximal to OSGroup B: disc spines stellateOphiomitrella mutata Koehler, 190410dense, trilobed stumps1/10 of dd, triangular, widely separatedrounded, rhombic, distal lobenarrow crescent, proximal to OSOphiomitrella polyacantha (H.L. Clark, 1911)6stellate stumps, crown with perpendicular thorns1/6 of dd, triangular, widely separatedrhomboid, proximally acutetrapezoid, proximal to OSOphiomitrella sagittata Koehler, 19229dense, strong, trilobed head1/7 of dd, triangular, widely separatedarrowheadshaped, separating AScrescent to trapezoid, proximo-lateral to OSOphiomitrella stellifera Matsumoto, 19174stellate stumps, crown with 6 thorns1/10 of dd, triangular, separatedrhombic to arrowheadshaped, larger than AStrapezoid, proximal to OSOphiomitrella subjecta Koehler, 19229dense, short, club-shaped, thorny head1/9 of dd, triangular, separatedrhombic, proximally acutenarrow crescent, proximal to OSGroup C: disc spines elongated stump-like with thornsOphiomitrella barbara Koehler, 19047long stumps with thorny crownas disc scales, widely separatedrhombic, proximally acutenarrow crescent, proximal to OSOphiomitrella chilensis Mortensen, 19525thorny stumps~1/8 of dd, triangular, distally connectedrhombic, distal lobetrapezoid, extending around OSOphiosemnotes clavigera (Ljungman, 1865)6.5long and short thorny stumpsrounded separatedrhombictrapezoidOphiosemnotes conferta (Koehler, 1922)6elongated thorny stumps1/4 of dd triangular, halfway connectedrounded rhombic, larger than AScrescent, proximal to OSOphiosemnotes corynephora (H.L. Clark, 1911)8cylindrical stumps~1/6 of dd, rounded triangularrhombictrapezoid, proximal to OSOphiosemnotes hamata (Mortensen, 1933)4cylindrical stumpsrounded triangular, distally connectedrhombic, larger than AScrescent, proximal to OSOphiosemnotes ingrata (Koehler, 1908)4low stumps1/10 of dd, round, widely separatedrounded rhombiccrescent, proximal to OSOphiosemnotes pachybactra (H.L. Clark, 1911)11club-shaped stumps~1/6 of dd, rounded triangular, distally connectedrounded rhombic, as large as AScrescent to trapezoid, proximal to OSOphiosemnotes paucispina (H.L. Clark, 1911)10rounded granules1/6 of dd, oval, widely separatedrhombictrapezoid* Ophiosemnotes tylota (H.L. Clark, 1911)10stout thorny stumps1/6 of dd, rounded triangular, distally connectedrhombictrapezoid, proximal to OSGroup D: bar-like radial shields* Ophiomitrella laevipellis (Lyman, 1883)4.5scattered low granulespear-shaped (distal ends), bar-like ridge in discrhombic to triangular, smaller than AStrapezoid to crescent, proximal to OSOphiomitrella porrecta Koehler, 19146.5dense multifid spinessmall as scales (distal ends), widely separatedpentagonalcrescent, proximal to OS