TABLE 3 in Taxonomic significance of test morphology in the echinoid genera Diadema Gray, 1825 and Echinothrix Peters, 1853 (Echinodermata)

TABLE 3. — Test measurements, proportions and features for Diadema savignyi Michelin, 1845 and D. setosum (Leske, 1778). Abbreviation: SD, standard deviation.
D. savignyiD. setosumOrigin of specimens examinedSeychelles, Japan, New Cale-Mauritius, Indonesia, Australia,donia, Cook Islands, Samoa, FijiNew Caledonia, Fiji, PhilippinesTest colourblackblackTest shapehemisphericalhemisphericalTest distinctionsambulacra slightly raised aborallyambulacra slightly raised aborallyIridophore pattern (interambulacra)blue lines (bold)lines of blue spotsIridophore pattern (apical system)blue ring (bold)no apical ringIridophore pattern (genital plate)blue arch (bold)blue spot of iridophoresMean horizontal test diameter (SD)68 mm (4.2 mm)76 mm (3.7 mm)Mean vertical test diameter (SD)38 mm (2.1 mm)40 mm (2.9 mm)Maximum horizontal test diameter observed78 mm84 mmMaximum vertical test diameter observed44 mm48 mmMarkings on test (median area ofwhite spot marking (typicallywhite spot marking (day andinterambulacra)night only)night)Markings on naked test (median area ofgeographic variation, white spot/white line and spot markingsinterambulacra)no spotMarkings on naked test (genital plate)distinct arched depressiongreen/blue spot marking(typically)Number of tubercles on genital plate1-3 tubercles3-5 tuberclesHeight to width (at widest point) ratio of0.69:10.72:1genital plateDiameter of gonopore (% of genital plate28%25%height)Form of apical systemhemicyclichemicyclicForm of periproct (distinguishing features)small black, no ring or plateletssmall black, orange ring, noplateletsApical system (% of horizontal test diameter)22-28%22-28%Periproct (% of horizontal test diameter)13-18%12-20%Peristome (% of horizontal test diameter)42-50%40-50%Ambulacra % of interambulacra (at ambitus)28-30%25-30%Tubercle structureperforate and crenulateperforate and crenulateNumber of median series of tubercles onvariable (1 or 2)variable (1 or 2)interambulacraRudimentary tube feet present on thenonoperistomeBuccal tube feet present5 pairs5 pairsSpines present on the buccal platesnonoNumber of specimens examined200200