Spectamen martensi, Herbert, David G., 2015

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 : 48

Spectamen martensi sp. n.

( Figure 6 E–G)

Spectamen semisculptum (non Cyclostrema semisculptum Martens, 1904 )— Herbert, 1987c: 369, figs 120k, 179–183 (including protoconch and radula ).

The material discussed as Spectamen semisculptum by Herbert (1987c) was referred to Martens’ taxon with some hesitation since the type material was not then available to be consulted due to political considerations. Subsequent examination of the two syntypes (ZMB) revealed that they represent juvenile specimens of the variable ‘ Solariella ’ intermissa Thiele, 1925 . Being an earlier name, semisculptum must take precedence (see Zetela semisculpta ). As a result, the material identified as Spectamen semisculptum by Herbert (1987c) lacks a name. To remedy this I here propose the name Spectamen martensi for this species and provide a formal description below.

Examined material (all NMSA, dredged R.V. Meiring Naudé): Holotype: South Africa, E. Cape, Transkei, off Waterfall Bluff (31°30.15ʹS: 29°55.8ʹE), 300 m, st’n E12 (C9714/T4032); diameter 4.5 mm, length 3.7 mm. Paratypes (3): KwaZulu-Natal: off Melville (30º43.1ʹS: 30º39.2ʹE), living, 380–420 m, coarse sand, sandstone, little life, st'n X8, 22 /vii/1982 (B8849/T4079, one specimen; D4381/T4080, one specimen, living). E. Cape: same data as holotype (P0340/T4033, one specimen).

Diagnosis. Shell small, whitish, without colour pattern; slightly wider than high; whorls rounded, without shoulder; sculptured by close set spiral lirae, not corded; axial sculpture of sub-sutural and umbilical pliculae.

Description. Shell small, turbiniform, height moderate (L/D = 0.77–0.89); whorls evenly rounded and lacking shoulder; suture slightly sunken; periphery at mid-whorl; protoconch large and globose, diameter 600–800 Μm; teleoconch of up to three whorls. Sculpture of spiral lirae and axial pliculae; spiral lirae begin at start of teleoconch, approx. 10 on first whorl (only visible in freshest shells) becoming more numerous in later whorls as intermediaries develop; lirae similar on base and in umbilicus. Axial sculpture of close set sub-sutural pliculae starting near beginning of second whorl; pliculae obsolete toward periphery but reappear on base near umbilicus. Umbilicus deep, relatively narrow but expanding rapidly; margin evenly rounded, pliculate. Aperture almost circular, peristome virtually complete; outer lip prosocline, smooth; interior not obviously nacreous.

Colour: White, translucent, dark colour of visceral mass shows through apex of live-taken specimens.

Dimensions: Largest specimen, diameter 4.7 mm. length 3.6 mm

Radula ( Herbert 1987c: fig. 183): Rachidian and inner laterals broader than in other local forms, similar to those of S. philippense ; outer lateral long and slender; latero-marginal plate short.

External anatomy: As in S. pardalis , mantle cavity dark brown.

Distribution. Southern KwaZulu-Natal (off Melville) to E. Cape (off Waterfall Bluff), 300–420 m (living 380–420 m).

Notes. With its rounded whorl profile, close-set spiral liration and large protoconch, Spectamen martensi is most similar to S. multistriatum ( Thiele, 1925) . That species, however, is larger and lacks axial pliculae. The large protoconch suggests that, like several other South African species of Spectamen , this taxon broods its developing larvae in the mantle cavity ( Herbert 1987c).

Etymology. The species is named in honour of the German malacologist K.E. von Martens (1831–1904).

Figures

FIGURE 6. A – D, Falsimargarita glaucophaos (Barnard, 1963), syntype, diameter 12.5 mm (SAM A 9830). E – G, Spectamen martensi sp. n., holotype, off Waterfall Bluff, E. Cape, 300 m, diameter 4.5 mm (NMSA C 9714 / T 4032). H – L, Jujubinus hubrechti Poppe, Tagaro & Dekker, 2006, H, I, off Ponta Techobanine, southern Mozambique, 90 – 100 m, length 6.0 mm and 7.2 mm respectively (NMSA L 8392), J – L, off Gipsy Hill, KwaZulu-Natal, 110 m, length 5.3 mm and 6.0 mm respectively (NMSA E 3716). M, N, Crosseola foveolata (Barnard, 1963), M, SSE of Tsitsikamma, E. Cape, 275 – 285 m, length 2.8 mm (NMSA V 3610), N, oblique view of base, SSE of Knysna, W. Cape, 101 m, diameter 2.33 mm (NMSA V 1793). O – Q, Turbo tursicus Reeve, 1848, off Rocktail Bay, KwaZulu-Natal, 65 m, length 14.3 mm (NMSA D 6362). R, S, Stomatia phymotis Helbling, 1779, coral reefs off Kosi Bay, KwaZulu-Natal, 18 – 22 m, length 20.5 mm (NMSA S 1068). [Images not to scale.]