Amalda marginata

Amalda marginata
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Neogastropoda
Family:	Ancillariidae
Genus:	Amalda
Species:	A. marginata
Binomial name
Amalda marginata (Lamarck, 1811)
Synonyms
Amalda (Alocospira) marginata(Lamarck, 1811) Amalda dyspetes(Iredale, 1929) Ancillaria marginataLamarck, 1811 (original combination) Ancillaria marginata var. tasmanicaTenison Woods, 1877 junior subjective synonym Baryspira (Alocospira) dyspetesIredale, 1929

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

Description

The length of the shell attains 40 mm, its diameter 19 mm.

(Original description in French) It is an oval, rounded shell with a pointed, transversely keeled spire. It is whitish with a smooth back, but its whorls are decorated near their suture with an interrupted reddish band. The outer lip of its aperture is equipped with a small protruding denticle at the bottom. ^[2]

(Described as Baryspira (Alocospira) dyspetes) The shell is medium-sized with an open aperture and a slightly swollen shape. The spire is very short and tapered. The shell is primarily white, with a yellow band just behind the suture and a similarly colored anterior canal. The apex consists of two rounded whorls, followed by five nearly smooth adult whorls, with only a faint, central spiral ridge visible. The base of the shell displays about six shallow grooves. The inner lip is covered with a thin glaze that extends beyond the aperture onto the previous whorl. ^[3]

(Described as Ancillaria marginata var. tasmanica) The shell is ovate-fusiform, solid, with a pyramidal spire shorter than the aperture. It is covered with two spiral keels. The shell is entirely white. The whorls are rounded and bordered above by a white callous band. The front of the body whorl is decorated with such bands in the following order —first with two equidistant spiral grooves, then with a thick, broad, rounded varix, followed by a broad, flattened band, and finally 4-5 spiral folds. The inner lip is somewhat sharp and thin. The outer lip is callous at the back. The aperture is wide, with a broad notch at the base. ^[4]

Distribution

This marine species is endemic to Australia and occurs off New South Wales, South Australia, Tasmania, Victoria and Western Australia.

References

1. Amalda marginata (Lamarck, 1811) . Retrieved through: World Register of Marine Species  on 28 April 2010.
2. Lamarck, J.B.M. de (1811). "Suite de la détermination des espèces de Mollusques testacés. Tarrière (Terebellum), Ancillaire (Ancillaria), Olive (Oliva)". Annales du Muséum National d'Histoire Naturelle. 16: 304. Retrieved 13 November 2024.
3. Iredale, T. (1929). "Strange molluscs in Sydney Harbour". Australian Zoologist. 5 (4): 341. This article incorporates text from this source, which is in the public domain .
4. Tenison Woods, J.E. (1877). "On some new Tasmanian marine shells. (Second series)". Papers and Proceedings and Report of the Royal Society of Tasmania. 1876: 135. This article incorporates text from this source, which is in the public domain .

External links

• Gemmell, Michael R.; Trewick, Steven A.; Hills, Simon F. K.; Morgan-Richards, Mary (2019). "Phylogenetic topology and timing of New Zealand olive shells are consistent with punctuated equilibrium". Journal of Zoological Systematics and Evolutionary Research. 58 (1): 209–220. doi: 10.1111/jzs.12342 .