Amalda optima (Sowerby III, 1897)

Kantor, Yuri I., Castelin, Magalie, Fedosov, Alexander & Bouchet, Philippe, 2020, The Indo-Pacific Amalda (Neogastropoda, Olivoidea, Ancillariidae) revisited with molecular data, with special emphasis on New Caledonia, European Journal of Taxonomy 706, pp. 1-59 : 52-53

Amalda optima (G.B. Sowerby III, 1897)

Fig. 19E

Ancilla optima Sowerby III, 1897: 7 , pl. 6 fig. 31.

Amalda optima – Gratecap 2012: 23, 29, fig. 23.

Type material

Possible syntype

SOUTH AFRICA • Durban; NHMUK 1899.4.14.648.

Material examined

One sequenced specimen ( Table 1).

Description

MEASUREMENTS. Shell large (SL up to 55 mm).

SHELL. Broadly ovate, with narrow base and low conical spire. Primary spire callus very thick, smooth and glossy, covering all whorls, except tip of protoconch, rendering measurements impossible. Secondary callus rather thick, with distinct anterior border, smooth and glossy, fusing without visible border with parietal callus, and reaching the shell apex. Plication plate smooth, poorly separated from anterior band, columella smooth. Olivoid groove distinct, labral denticle very short, obtuse. Anterior band smooth, upper anterior band nearly flat, lower anterior band weakly convex. Primary callus milky-caramel with distinct sinuous, narrow brown axial lines, particularly pronounced on last whorl, its narrow spiral brown line bordered abapically by lighter, narrow line. Secondary callus caramel to dark brown, turning very light, nearly white, above aperture. Body whorl cloak background light caramel with irregularly spaced, orthocline, brown axial bands of uneven width, olivoid band much lighter than cloak, creamy-coloured, anterior band very dark brown.

RADULA. Not studied.

Distribution

Natal to Mozambique.

Figures

Fig. 19. Sequenced species of Amalda H. Adams & A. Adams, 1853. A–B. Amalda sp., MNHN IM- 2013-63891, SL 20 mm. C–D. A. contusa (Reeve, 1864), MNHN IM-2009-22263, SL 24.9 mm. E. A. optima (G.B. Sowerby III, 1897), MNHN IM-2007-38287. F–G. A. monilifera (Reeve, 1864), MNHN IM-2013-63898, SL 11.7 mm. H–I. A. hinomotoensis (Yokoyama, 1922), MNHN IM-2019-618, SL41.4 mm.J–K.A.hayashii Ninomiya, 1988, MNHNIM-2013-44413,SL38.4 mm.L–M.A.bellonarum Kilburn & Bouchet, 1988, MNHN IM-2007-33273. Shells not to scale.