''Monodonta australis'',

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

the toothed topshell, is a species of

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

, a marine

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusk in the family Trochidae, the top snails.

Description

The size of the shell varies between 12 mm and 35 mm. The shell is similar to ''

Monodonta labio ''Monodonta labio'', common name the toothed top shell or the lipped periwinkle, is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails. Distribution This species occurs in the Indian Ocean off Madaga ...

'', but with rounder

whorl A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral ...

s, more marked sutures and with lower lirae. It is not granulose. It is tessellated with black and grayish or greenish. The penultimate whorl is subangulate by the prominence of its central rib. The columella is much less strongly dentate than in ''Monodonta labio'', and the notch or canal below it shallow. The basal plicae are less developed than in ''Monodontia labio''.Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
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Distribution

This marine species occurs off South Africa and in the Indian Ocean off Madagascar,

Aldabra Aldabra is the world's second-largest coral atoll, lying south-east of the continent of Africa. It is part of the Aldabra Group of islands in the Indian Ocean that are part of the Outer Islands of the Seychelles, with a distance of 1,120 k ...

and the Mascarene Basin; also off

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

References

* Williams S.T., Donald K.M., Spencer H.G. & Nakano T. (2010) ''Molecular systematics of the marine gastropod families Trochidae and Calliostomatidae (Mollusca: Superfamily Trochoidea)''. Molecular Phylogenetics and Evolution 54:783–809.

External links

* {{DEFAULTSORT:Monodonta Australis australis Gastropods described in 1816