Ilanga bicarinata bicarinata ( A. Adams & Reeve, 1850 )

Herbert, David G., 2015, An annotated catalogue and bibliography of the taxonomy, synonymy and distribution of the Recent Vetigastropoda of South Africa (Mollusca), Zootaxa 4049 (1), pp. 1-98 : 44

Ilanga bicarinata bicarinata ( A. Adams & Reeve, 1850) —revised taxonomy

Margarita bicarinata A. Adams & Reeve, 1850 in 1848 – 1850: 49, pl. 11, fig. 11a, b. Type loc.: Eastern Seas [HMS Samarang], erroneous, here emended to Agulhas Bank; holotype in NHM (NHMUK 1879. 2.26.186), figured by Herbert (1987c: figs 217–219).

Solariella undata G.B. Sowerby (II), 1870: 251. E.A. Smith, 1906: 55. Barnard, 1963a: 236, fig. 10b, d, f. Kensley, 1973: 44, fig. 107. Type loc.: Agulhas Bank, S. Africa; two probable syntypes in NMW (55.158.05.52), none in NHM ( Herbert 1987c). Syn. nov.

Minolia undata — Martens, 1904: 47, pl. 5, fig. 5.

Solariella gratiosa Thiele, 1925: 15 [49], pl. 1[13], fig. 20. Type loc.: Valdivia St’n 103 (35°10.5ʹS: 23°02ʹE), 500 m [slope off Agulhas Bank, south of Knysna]; two syntypes in ZMB (in poor condition). Syn. nov.

Solariella valdiviae Thiele, 1925: 13 [47] pl. 1[13], fig. 15. Type loc.: Valdivia St’n 104 (35°16ʹS: 22°26.7ʹE), Agulhas Bank, off Mossel Bay, 155 m; holotype in ZMB. Syn. nov.

Ilanga bicarinata — Herbert, 1987c: 380, figs 217–219.

Ilanga gratiosa — Herbert, 1987c: 305.

Ilanga undata undata — Herbert, 1987c: 326, figs 80–84, 86, 87.

Distribution. Algoa Bay (off Cape Recife) to Atlantic Cape (off Namaqualand); 108–400 m (living 108–171 m).

Notes. The ‘Eastern Seas’ locality cited as the ‘habitat’ for many taxa described from the voyage of HMS Samarang is notoriously vague and frequently erroneous ( Petit 2007; Herbert 2013). In 1987, I speculated that Margarita bicarinata A. Adams & Reeve, 1850 might be another example of a South African taxon being incorrectly localised as originating from ‘Eastern Seas’. At that time, however, the solariellid fauna of the central Indo-West Pacific was little known and, erring on the side of caution, I was reluctant to definitively conclude that Margarita bicarinata was in fact a South African rather than an oriental species. In the intervening years the solariellid fauna the ‘Eastern Seas’ has become better documented ( Poppe Tagaro & Dekker 2006; Poppe & Tagaro 2008c; Vilvens 2009; Williams et al. 2013; Vilvens, Williams & Herbert 2014; Vilvens & Williams in press), but no species resembling Margarita bicarinata has been encountered. As a result, I believe it can be justifiably concluded that Margarita bicarinata was originally mislocalised and that it is in fact the Agulhas Bank taxon currently known by the name Ilanga undata undata . Similarly mislocalised South African species include Marginella diadochus A. Adams & Reeve, 1848 , Pleurotoma impages Adams & Reeve, 1848 and Turritella declivis A. Adams & Reeve in Reeve, 1849 (Herbert 2013).

The syntypes of Solariella gratiosa Thiele, 1925 are in poor condition, but appear to represent elevated specimens of Ilanga b. bicarinata .