Description

Description. Test oval, domed centrally, with moderately thickened margin (TL = 119.2 mm; TW = 120.1 mm) (Fig. 14 A – D). Apical system monobasal, with five gonopores (Fig. 14 I). Petaloid large (Fig. 14 A, C). Petals bowed and distally open (Fig. 14 C). Posterior petals slightly longer than anterior ones (Fig. 14 C). Six short, broad and drop-shaped lunules, larger in the anterior portion of the body (Fig. 14 A – D). Anal lunule extends between posterior petals (Fig. 14 A – D). Aboral primary spines short and club-shaped, uniformly covering test. Miliary spines with sac-like structure on tip, densely scattered among primary spines. Lunules with two types of spines; long spines, narrow at base and with broad tip (like swim fins) on aboral margins, and long, uniformly thin spines internally. Oral surface flat (Fig. 14 B, D), with long and thin locomotory spines that are slightly curved at base, and short and slightly curved secondary spines. Peristome pentagonal, slightly anterior (Fig. 14 B, D). Periproct oval and anterior to anal lunule (Fig. 14 B, D), not in contact with basicoronal. Periproctal membrane covered by plates of variable shapes and sizes, largest occurring on distal margin of periproct. Basicoronal plate small. Five food grooves bifurcating at edge of basicoronal plates, each branch surrounding the lunules (Fig. 14 D). Pedicellariae. Pedicellariae over entire test, but more abundant on oral surface and near the lunules, peristome, and periproct. Bidentate pedicellariae with long neck and short head. Valves short, with narrow and slightly curved bases, median region enlarged with serrated margins and one end tooth, which crosses terminal tooth of opposing valve (Fig. 14 E – H). Colour. Brown or greenish (Fig. 14 A, B, 18 H). Naked test white (Fig. 14 C, D).

Common Names

Taxonomic Hierarchy

Kingdom: Animalia

Phylum: Echinodermata

Class: Echinoidea

Order: Echinolampadacea

Family: Mellitidae

Genus: Encope

Species: Encope emarginata (Leske, 1778)