''Heterocithara rigorata'' 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 Mangeliidae.WoRMS (2009). Heterocithara rigorata (Hedley, 1909). In: MolluscaBase (2017). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=434005 on 2017-07-17

Description

The length of the shell attains 3.8 mm, its diameter 1.5 mm. (Original description) The small, oblong shell is turreted and rather solid. Its colour is dull white. It contains 6

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, including a smooth three-whorled

protoconch A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called ...

. whose initial whorl is eccentric. The sculpture shows from ten to twelve very prominent, close, radial ribs, widest apart on the back of the

body whorl The body whorl is part of the morphology of the shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk. In gastropods In gastropods, the b ...

, and becoming closer on the earlier whorls. These ribs project on the summit of the whorl and fade gradually on the base. The body whorl is encircled by twelve to fourteen strong spiral cords, which override both ribs and interstices. On the penultimate whorl there are four such cords, and on the antepenultimate three. Between and parallel to the spiral cords are fine, close, microscopic hairlines. The aperture is narrow linear, with a deep sinus and a prominent

varix A varix (pl. varices) is an abnormally dilated vessel with a tortuous course. Varices usually occur in the venous system, but may also occur in arterial or lymphatic vessels. Examples of varices include: * Varicose veins, large tortuous veins usua ...

Some variation in contour occurs, some individuals being shorter and broader than others. The species is characterised by its straight, narrow form, gradate spire, and strongly modelled sculpture. Hedley, C. 1922. A revision of the Australian Turridae. Records of the Australian Museum 13(6): 213–359, pls 42-56

Distribution

This marine species is endemic to Australia and occurs off Queensland.

References

External links

Tucker, J.K. 2004 ''Catalog of recent and fossil turrids (Mollusca: Gastropoda)''. Zootaxa 682:1–1295
{{DEFAULTSORT:Heterocithara Rigorata rigorata Gastropods described in 1909 Gastropods of Australia Taxa named by Charles Hedley