''Crossea biconica'' is a species of small

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 ...

micromollusc A micromollusk is a shelled mollusk which is extremely small, even at full adult size. The word is usually, but not exclusively, applied to marine mollusks, although in addition, numerous species of land snails and freshwater mollusks also r ...

, a

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

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 ...

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

in the family

Conradiidae Conradiidae is a taxonomic family (created in 1987 by Golikov & Starobogatov) of very small sea snails, marine gastropod molluscs or micromolluscs. These genera were previously included in the polyphyletic family Skeneidae. They belong with ...

.Bouchet, P. (2012). ''Crossea biconica'' Hedley, 1902. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=596655 on 2012-09-01

Description

(Original description by Charles Hedley) The height of the shell attains 1.7 mm, its diameter 1.6 mm. The minute but solid, white shell has a biconical shape. Its base is greatly produced, the periphery keeled. The four

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 are somewhat turreted. Sculpture : The first and second whorls are smooth, the third comparatively coarsely cancellated, the fourth contains dense fine spiral cords crossed by fainter growth lines which tend to bead the interstices. The base is two-thirds of the total height. The wide and deep umbilicus is bordered by a conspicuous ridge, and has an elevated funicle winding within. The oblique aperture is rhomboidal, channelled by the umbilical ridge, and with a gutter at the termination of the funicle. A heavy outstanding varix occurs a short distance behind the aperture. The small size, produced base, and wide umbilicus are characters which distinguish this from other Australian members of the genus.Hedley Charles (1902) Studies on Australian Mollusca. Part VI; Proceedings of the Linnean Society of New South Wales vol. 27 (1902)
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Distribution

This marine species is endemic to Australia. It is found off the Northern Territory and Queensland

References

* Hedley, C. 1902. ''Studies on Australian Mollusca. Part VI.'' Proceedings of the Linnean Society of New South Wales 27: 7-29 * Cotton, B.C. 1959. ''South Australian Mollusca. Archaeogastropoda''. Handbook of the Flora and Fauna of South Australia. Adelaide : South Australian Government Printer 449 pp.

External links

To World Register of Marine Species
{{Taxonbar, from=Q5188539 biconica Gastropods described in 1902