Illustrated guide to the echinoid (Echinodermata: Echinoidea) fauna of South Africa Author Filander, Zoleka Author Griffiths, Charles text Zootaxa 2017 4296 1 1 72 journal article 32399 10.11646/zootaxa.4296.1.1 ad746972-3837-4f1d-bf97-c09e5d7f1bd5 1175-5326 843325 EFE86EDD-D170-4D97-87D9-3125400713EC Stereocidaris excavata Mortensen, 1932b Fig. 12 A–C. Stereocidaris excavata Mortensen, 1932b . 151–154. Pl. II, Figs 1–5 . Pl. IV, Fig. 2 . Pl. XI, Fig. 1–2 ; Clark & Courtman-Stock, 1976 : 217; Schultz, 2011 : 1040. Material examined. MBC-A023320; MBC-A077747; MBC-A077745; MBC-A077748; MBC-A077746; MBC- A077744. Identification. Similar to Stereocidaris capensis ; but differs in sunken apical disc, which has centrally positioned and slightly raised gonopores. Primary spines slender, somewhat fluted, rugose, with about 12 finely serrate, low ridges; secondaries adpressed, chisel-like in shape. Denuded test creamish, with green tint. Global maximum size. Maximum test diameter 69 mm . Global distribution. Endemic to the South coast region of South Africa, at 120–177 m depth ( Mortensen 1932b ; Clark & Courtman-Stock 1976 ; Schultz 2011 ). Remarks. Both S. capensis and S. excavata are restricted to South African waters; they may, however, be differentiated by their primary spines and apical discs. S. capensis has fusiform, stout primary spines with 20 longitudinal ridges and an elevated apical disc with distally arranged gonopores; whilst S. excavata has fluted, slender primary spines with 12 low serrations and a distinctively sunken apical disc with centrally positioned, elevated gonopores.