Argalista fluctuata

Argalista fluctuata
Shell of Argalista fluctuata (specimen at Naturalis Biodiversity Center)
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Vetigastropoda
Order:	Trochida
Superfamily:	Trochoidea
Family:	Colloniidae
Subfamily:	Colloniinae
Genus:	Argalista
Species:	A. fluctuata
Binomial name
Argalista fluctuata (Hutton, 1883)
Synonyms
Cyclostrema fluctuataHutton, 1883 Cyclostrema fluctuatumF. W. Hutton, 1883 (superseded combination with corrected gender ending) Homalopoma (Argalista) fluctuata(Hutton, 1883) Leptothyra fluctuataSuter, 1913 Homalopoma (Argalista) fluctuataPowell, 1979

Argalista fluctuata is a species of small sea snail with calcareous opercula, a marine gastropod mollusk in the family Colloniidae. ^[1]

Description

The small, rather solid shell is spirally striated. It is not iridescent. Its colour is yellowish white or pale brownish with irregular waved longitudinal bands of brown, which are rather indistinct. The spire is depressed and obtuse. The shell contains four whorls. They are rounded and distinctly and closely spirally grooved. The umbilical region is smooth. The suture is scarcely impressed. The narrow umbilicus is deep. The aperture is subrotund. The peristome is acute and not continuous. The lower lip is thickened. The rather thick, white operculum is subcalcareous. It is round and translucent. It contains about six slowly increasing whorls. ^[2]

Distribution

This marine species is endemic to New Zealand and occurs off Southern South Island and Stewart Island, Snares Islands, Antipodes Islands, Bounty Islands and Chatham Island.

References

1. Argalista fluctuata (Hutton, 1883) . 22 October 2025. Retrieved through: World Register of Marine Species .
2. Hutton, F.W. 1883. Art. IX.—Notes on some marine Mollusca, with descriptions of new species. Transactions and Proceedings of the New Zealand Institute, 16: 212-216.

• Powell, A.W.B. 1979 New Zealand Mollusca: Marine, Land and Freshwater Shells, Collins, Auckland
• H.G., Marshall, B.A. & Willan, R.C. (2009). Checklist of New Zealand living Mollusca. Pp 196-219. in: Gordon, D.P. (ed.) New Zealand inventory of biodiversity. Volume one. Kingdom Animalia: Radiata, Lophotrochozoa, Deuterostomia. Canterbury University Press, Christchurch.
• Poppe, G.T., Tagaro, S.P. & Huang, S.-I. (2023). The recent Colloniidae with a study of the Colloniidae collected by various expeditions of the Muséum national d'Histoire naturelle, Paris. Harxheim: ConchBooks. 372 pp.
• Maxwell, P. A. (2009). Cenozoic Mollusca. Pp 232-254 in Gordon, D. P. (ed.) New Zealand inventory of biodiversity. Volume one. Kingdom Animalia: Radiata, Lophotrochozoa, Deuterostomia. Canterbury University Press, Christchurch

External links

• Suter, H. (1908). "Additions to the marine molluscan fauna of New Zealand, with descriptions of new species". Additions to the marine molluscan fauna of New Zealand, with descriptions of new species. 8: 27. Retrieved 22 October 2025.
• Homalopoma (Argalista) fluctuata (Hutton, 1883)
• Bruce A. Marshall, Molluscan and brachiopod taxa introduced by F. W. Hutton in The New Zealand journal of science; Journal of the Royal Society of New Zealand, Volume 25, Issue 4, 1995