Schizaster lacunosus (Linnaeus, 1758)

Fig. 75 A–D.

Schizaster ventricosus: A. Agassiz, 1872 –1874: 158, 614.

Schizaster japonicus: A. Agassiz, 1881: 202, Pl. XXXVI, Figs 8–13. Pl. XLIII, Fig. 26. Pl. LXV, Figs 7–10; Döderlein, 1906: 254.

Schizaster lacunosus: H.L. Clark, 1924: 12; H.L. Clark, 1925a: 210; Clark & Courtman-Stock, 1976: 248.

Ova (Aplospatangus) lacunosus: Schultz, 2010: 443, Fig. 826.

Material examined. MBC-A 022232; MBC-A 022888; MBC-A 022889; MBC-A023318; MBC-A027744; MBC- A027745; MBC-A077988; MBC-A077987; MBC-A077767; MBC-A077990; MBC-A077989.

Identification. Test heart-shaped, pointed towards the end, very high posteriorly, with indented anterior ambulacra, adjoining interambulacra rising as vertical wall covering frontal pore-pairs, posterior interambulacra keeled forming a hook above periproct; genital pores two.

Global maximum size. Maximum test length 82 mm.

Global distribution. Japan, East Coast of Africa extending to South coast of South Africa, Northeast Australia (Mortensen 1951), at 5–198 m depth.

Remarks. Samples identified through this study extend previously known distribution southwards to off Port Elizabeth; and illustrate that species may be found in deeper waters of 198 m than the previously thought 90 m. Very similar to Brisaster capensis, but differs in number of gonopores, of which S. lacunosus has two and B. capensis three. Other differences that distinguish the two species are the posterior keel and the two vertical walls formed by the adjoining anterior interambulacra in S. lacunosus . Schultz (2010) reported this species as Ova (Aplospatangus) lacunosus on the basis of fossil type known to have four gonopores, thus resulting in the genus Schizaster being synonymized with Paraster and species with two gonopores being transferred to genus Ova . However, this change has not been implemented on the WED database and this study follows the taxonomic naming of the WED database.