Spatagobrissus mirabilis H.L Clark, 1923

Fig. 71 A–C.

Spatagobrissus mirabilis H.L. Clark, 1923: 402 –2002. Pl XXIII; A.M. Clark, 1977: 480; Mortensen, 1951: 492 –494. Pl. XXVIII, Figs 10–12. Pl. LX, Fig. 8; Clark & Courtman-Stock, 1976: 250; Schultz, 2010: 403, Figs 757–761.

Material examined. MBC-A 022292; MBC-A 022331; A22646; MBC-A 022336; MBC-A 022342; MBC- A 022346; MBC-A 022348; MBC-A 022636; MBC-A 022648; MBC-A077972; MBC-A077973; MBC-A023377; A23401; A22962.

Identification. Test large, with round outline, pointed at posterior end, aboral side somewhat sloping; petals broad, short, closed distally, with peripetalous fasciole running at distal ends. Spines short and numerous. Live specimen brown in color, denuded test white.

Global maximum size. Maximum test length 110 mm.

Global distribution. Endemic to West and South coast regions of South Africa, at 20–32 m depth (Clark & Courtman-Stock 1976).

Remarks. Samples from the Iziko Museum collection extend previously known distribution westwards to False Bay. Species combines features of genera Spatangus and Brissus of which the petals, mouth and posterior part of test resembles Spatangus spp. whilst the presence of the peripetalous fasciole and position of periproct resembles Brissus spp. (H.L. Clark 1923). Differs from Eurypatagus parvituberculatus in the test slightly sloping on upper-side, by presence of conspicuous peripetalous fasciole and by having shorter petals.