''Heterocithara tribulationis'' 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 tribulationis (Hedley, 1909). In: MolluscaBase (2017). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=434009 on 2017-07-17

Description

The length of the shell attains 4.75 mm, its diameter 2.5 mm. (Original description) The small, solid shell has a biconical shape and is angled at the periphery. Its colour is white or buff. 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 small smooth two-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 ...

. The sculpture shows about a dozen undulatory radial ribs, equal in breadth to their rounded interstices. They arise at the suture and are most prominent on the shoulder, and fade on the base. Ascending the spire, these radials gradually diminish. About twelve small spiral threads, which traverse ribs and furrows alike, are evenly distributed between the shoulder and the anterior extremity. Finally, a secondary sculpture of fine close grains, arranged radially and spirally, is spread over the whole surface, giving a *'gritty" aspect to the shell. The aperture is narrow, protected by a strong projecting

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 ...

. The outer lip shows two or three ill-defined tubercles within. The

siphonal canal The siphonal canal is an anatomical feature of the shells of certain groups of sea snails within the clade Neogastropoda. Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is ...

is short. The strong shoulder angle and sanded surface are the principal features. 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 Tribulationis tribulationis Gastropods described in 1909 Gastropods of Australia Taxa named by Charles Hedley