''Vanitrochus tragema'' 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
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 ...
mollusk in the
family Trochidae, the top snails.
[Bouchet, P. (2012). ''Vanitrochus tragema'' (Melvill & Standen, 1896). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=547295 on 2012-11-23]
Description
The size of the shell varies between 1.8 mm and 4 mm.
(Original description)This is a small conical chalky-white shell, colourless excepting for scattered transverse pink flames round the upper parts of the lower
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 just below the sutures. The shell is profoundly but narrowly umbilicate. The shell contains six whorls six, two being in the
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 ...
, slantingly angled in a gradate manner. The surface is closely acutely ribbed, the transverse decussations somewhat noticeable in the interstices, and these in some specimens give a crenulate appearance to the ribs themselves. The base
is spirally costulate, as are the upper whorls. The
aperture is round. The outer
lip is simple.
Melvill, J.C. & Standen, R. 1896. ''Notes on a collection of shells from Lifu and Uvea, Loyalty Islands, formed by the Rev. James and Mrs. Hadfield, with list of species. Part II''. Journal of Conchology 8(9): 273-315, pls 9-11
/ref>
Distribution
This marine species occurs off the Loyalty Islands, Tuvalu, and Australia ( Queensland)
References
* Hedley, C. 1899. ''The Mollusca of Funafuti. Part 1. Gastropoda''. Memoirs of the Australian Museum 3(7): 395-488
* Iredale, T. 1929. ''Queensland molluscan notes, No. 1.'' Memoirs of the Queensland Museum 9(3): 261-297, pls 30-31
* Herbert, D. G. (1989). Pagodatrochus, a new genus for Minolia variabilis H. Adams, 1873 (Gastropoda: Trochidae. Journal of Molluscan Studies. 55: 365-372.
* Wilson, B. 1993. ''Australian Marine Shells. Prosobranch Gastropods''. Kallaroo, Western Australia : Odyssey Publishing Vol. 1 408 p
External links
To Encyclopedia of Life
To World Register of Marine Species
*
{{Taxonbar, from=Q7915002
tragema
Gastropods described in 1896