Description

Description. Test elliptical or oval (TL = 3.3 to 21.9 mm; TH = 2.9 to 9.4 mm), low, with rounded ends (Fig. 9 A, C, D) and densely covered by slender, glassy and short spines. Peristome and periproct on oral surface (Fig. 9 C). Apical system tetrabasal with four genital pores (Fig. 9 A, B). Ambulacra narrow, ambulacra II, III and IV slightly narrower than ambulacra I and V (Fig. 9 A, D). Petals undeveloped, pores double throughout and arranged uniserially. Interambulacra large, 1, 4 and 5 larger than 2 and 3 (Fig. 9 A). Ambulacral plate trigeminate. Tubercles imperforate, smooth and non-crenulate (Fig. 9 A, C, D). Pedicellariae present over whole test. Oral surface flat, except peristome, which is slightly concave (Fig. 9 C). Periproct oval, close to the peristome, about twice the size of peristome (Fig. 9 C). Peristomial plates diminishing in size from margin towards center. Peristome central or slightly anterior, oblique, and depressed (Fig. 9 C). Periproctal plates imbricate, decreasing in size from margin to center. Pedicellariae. According to Westergren (1911), ophicephalous pedicellariae are the most numerous, especially on the aboral side. Tridentate pedicellariae scarce and found only on the oral side of the test, near or a short distance from the peristome and periproct. Globiferous pedicellariae found only near the ambitus, and rarely on the apical system. Triphyllous pedicellariae found only rarely; when present, they occur mostly in the ambulacra. Colour. From pale brownish cream to deep red, generally light red, with red tube feet (H. L. Clark 1921). According to Hendler et al. (1995), the tube feet vary from conspicuously brown to light brown and the spines are whitish to light brown. Naked test white or yellowish (Fig. 9 A – D).

Common Names

Taxonomic Hierarchy

Kingdom: Animalia

Phylum: Echinodermata

Class: Echinoidea

Order: Echinoneoida

Family: Echinoneidae

Genus: Echinoneus

Species: Echinoneus cyclostomus Leske, 1778