Hygrosoma petersii ( A. Agassiz, 1880 )

Filander, Zoleka & Griffiths, Charles, 2017, Illustrated guide to the echinoid (Echinodermata: Echinoidea) fauna of South Africa, Zootaxa 4296 (1), pp. 1-72 : 22

Hygrosoma petersii ( A. Agassiz, 1880)

Fig. 19 A–C.

Phormosoma petersii: A. Agassiz, 1879: 76 .

Hygrosoma petersi: Clark & Courtman-Stock, 1976: 220 .

Hygrosoma petersii: Mortensen, 1935: 202 –208. Pls. XIII–XVII. Pl. XVIII, Fig. 2 . Pl. XIX, Fig. 2 . Pl. LXXVIII, Figs I, 3–5, 24, 25; Schultz, 2011: 1099, Figs 1923–1924.

Echinosoma petersii: H.L. Clark, 1925a: 56 .

Material examined. A9812-079-DT; A22124; A22219 ; A22248; A22251.

Identification. Preserved test collapsed, with circular outline. Large oral tubercles with distinctive areoles, disappearing towards peristome. Pore-pairs in single series. Preserved test purple.

Global maximum size. Maximum test diameter 180 mm.

Global distribution. Widely distributed in North Atlantic from off South-West Ireland to Azores and Senegal and from off New Jersey, USA to West Indies, also reported from West coast of South Africa; at 200–3200 m depth range ( Schultz 2011).

Remarks. Clark & Courtman-Stock (1976) have flagged Clark’s (1923 & 1924) East coast record of the species as they point out it “is queried by Mortensen as unlikely to refer to this Atlantic species; at least one locality off Natal is duplicated by the British Museum specimen which proved to be referable to Sperosoma biseriatum ”. Differs from Araeosoma paucispinum in arrangement of pore-pairs, where Hygrosoma petersii has pore-pairs in a single series and A. paucispinum in oblique arcs forming three ventral series.

Figures

FIGURE 2. Body plan of an irregular echinoid or sand dollar (Clypeaster rarispinus), showing terminology of various body parts.

FIGURE 19. Hygrosoma petersii (SAMC-A 22219). A. Map showing distribution. B. Aboral view of preserved specimen. C. Oral view of preserved specimen.