Amalda optima

Amalda optima
Shell of Amalda optima
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Neogastropoda
Family:	Ancillariidae
Genus:	Amalda
Species:	A. optima
Binomial name
Amalda optima (G.B. Sowerby III, 1897)
Synonyms[1]
Ancilla optima G.B. Sowerby III, 1897

Amalda optima is a species of sea snail, a marine gastropod mollusk in the family Ancillariidae.[1]

Description

The length of the shell attains 55 mm.

The shell is broadly ovate with a narrow base and a low, conical spire. The primary spire callus is very thick, smooth, and glossy, covering all whorls except the tip of the protoconch, making measurements impossible. The secondary callus is also rather thick, with a distinct anterior border, smooth and glossy, merging seamlessly with the parietal callus and extending to the shell apex. The plication plate is smooth and poorly separated from the anterior band, and the columella is smooth as well. The olivoid groove is distinct, with a short, obtuse denticle on the outer lip. The anterior band is smooth, with the upper portion nearly flat and the lower portion slightly convex.

The primary callus has a milky-caramel color with distinct, sinuous, narrow brown axial lines that are especially pronounced on the body whorl. A narrow spiral brown line, bordered by a lighter line below, further accents the primary callus. The secondary callus ranges from caramel to dark brown, lightening to nearly white near the aperture. The body whorl is a light caramel with irregularly spaced, orthocline brown axial bands of varying width. The olivoid band is a creamy color, lighter than the rest of the shell, while the anterior band is a deep, dark brown. [2]

Distribution

This marine species occurs from Natal, South Africa to Mozambique. It was dredged at 100 m depth.

References

1. Amalda optima (G.B. Sowerby III, 1897). Retrieved through: World Register of Marine Species on 28 April 2010.
2. Yuri I. Kantor, Magalie Castelin, Alexander Fedosov, Philippe Bouchet (2020), The Indo-Pacific Amalda (Neogastropoda, Olivoidea, Ancillariidae) revisited with molecular data, with special emphasis on New Caledonia; European Journal of Taxonomy, [S.l.], n. 706, aug. 2020. ISSN 2118-9773  This article incorporates text from this source, which is available under the CC BY-SA 4.0 license.

• Steyn, D. G.; Lussi, M. (2005). Offshore Shells of Southern Africa: A pictorial guide to more than 750 Gastropods. published by the authors. p. 150.
• Gratecap, D. (2012). "Le genre Amalda en Afrique Australe". Xenophora. 140: 19–29.

External links

• Sowerby, G.B. III (1897). Appendix to marine shells of South Africa: a catalogue of all the known species with references to figures in various works, descriptions of new species, and figures of such as are new, little known, or hitherto unfigured. London: G.B. Sowerby III. p. 7. Retrieved 31 October 2024.