Clypeaster eurychorius H.L. Clark, 1925c

Fig. 56 A–D.

Clypeaster humulis: H.L. Clark, 1923: 392; H.L. Clark, 1925a: 149.

Clypeaster eurychorius H.L. Clark, 1924: 10 –11. Pl. III; Clark & Courtman-Stock, 1976: 241; Schultz, 2009: 539, Figs 913– 916.

Clypeaster (Stolonclypus) eurychorius: Mortensen, 1948d: 94 –96. Pl. XXX, Fig. 2. Pl. XXXI, Figs 2, 3. Pl. XXXII, Fig. 3. Pl. XXXIII, Fig. 2.

Material examined. MBC-A 022261; MBC-A 022286; MBC-A 022290; MBC-A023306; A22330; A28431; A23092.

Identification. Distinguished from other Clypeaster species within the region in having a rounded pentagonal test, flat except at elevated petal area, margin thick. Petals short, opened distally, pore-zones narrow, interporiferous zones wider. Primary tubercles sparse, miliaries smaller than primaries. Primary spines small, slender, longer towards mouth; miliaries slender, with thick tip. Preserved specimens brownish-green; denuded test uniformly yellowish-white.

Global maximum size. Maximum test length 145 mm.

Global distribution. South and East coast regions of South Africa, northward to Pemba Strait (Tanzania) and off Mauritius, at 125–320 m depth (Mortensen 1948d; Schultz 2009).

Remarks. Deep-water species, burrows in uppermost layer of sediment, where it feeds on organic particles.