Stereocidaris excavata Mortensen, 1932b Illustrated guide to the echinoid (Echinodermata: Echinoidea) fauna of South Africa Filander, Zoleka Griffiths, Charles Zootaxa 2017 4296 1 1 72 6ZRLD Mortensen, 1932 b Mortensen 1932 [151,653,393,419] Echinoidea Cidaridae Stereocidaris Animalia Cidaroida 16 17 Echinodermata species excavata    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 mdepth ( Mortensen 1932b; Clark & Courtman-Stock 1976; Schultz 2011).   Remarks. Both S. capensisand S.  excavataare restricted to SouthAfrican waters; they may, however, be differentiated by their primary spines and apical discs.  S. capensishas fusiform, stout primary spines with 20 longitudinal ridges and an elevated apical disc with distally arranged gonopores; whilst  S. excavatahas fluted, slender primary spines with 12 low serrations and a distinctively sunken apical disc with centrally positioned, elevated gonopores.