''Trochus calcaratus'', common name the actor top shell, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

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 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 e ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Trochidae The Trochidae, common name top-snails or top-shells, are a family of various sized sea snails, marine gastropod molluscs in the subclass Vetigastropoda. This family is commonly known as the top-snails because in many species the shell resemb ...

, the top snails.Gofas, S.; Rosenberg, G. (2014). Trochus calcaratus Souverbie in Souverbie & Montrouzier, 1875. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php/aphia.php?p=taxdetails&id=567739 on 2014-06-06 The name ''Trochus histrio'' was not well described by Reeve, and as was his custom in ''Trochus'', only a back view was given by Reeve, so that positive identification is difficult.

Description

The size of the shell varies between 18 mm and 40 mm. The solid, false-umbilicate shell has an elate-conic shape. The

spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires are ...

has nearly rectilinear outlines. The about 9

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 planulate, the body whorl is carinated. The sculpture of the upper surface consists of spiral series, four or five on each whorl, of regular, closely arranged granules, which are either rounded, bead-like, or laterally compressed. Upon the periphery of each whorl, there is a row of radiating, minutely perforated pustules, numbering on the body whorl 28. The base of the shell is concentrically sculptured with 6 to 7 concentric, densely granose lirae. It is slightly convex, radiately striped with brown or purplish. The color of the upper surface is whitish, broadly striped with red, purplish or brown. It is usually blue when rubbed. The

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...

is lirate within on outer and parietal walls. The basal margin is concave, thick, and dentate within. The

columella Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire. His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the wo ...

is oblique, plicate within and quadridentate. The white umbilical tract is biplicate.H. Pilsbry, Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
/ref> This species is principally distinguished by the fistulous or perforated peripheral tubercles.

Distribution

This species occurs on coral reefs and in the low and shallow subtidal zone in the Western and Central Pacific Ocean. In Australian waters it occurs off the

Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an states and territories of Australia, Australian territory in the central and central northern regions of Australia. The Northern Territory ...

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

and

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

References

* Reeve, L.A. 1848. ''Descriptions of new species of Trochus and Turbo, chiefly from the collection of H. Cuming.'' Proceedings of the Zoological Society of London 1848: 49-52 * Philippi, R.A. 1855. ''Trochidae''. pp. 249–328 in Küster, H.C. (ed). Systematisches Conchylien-Cabinet von Martini und Chemnitz. Nürnberg : Bauer & Raspe Vol. 2. * Lischke, C.E. 1869. ''Japanische Meeres-Conchylien. Ein beitrag zur kenntniss der Mollusken Japan's, mit besonderer rücksicht auf die geographische vertreitung derselben.'' Cassel : Fischer Vol. 1 192 pp., 14 pls. * Hedley, C. 1907. ''The Mollusca of Mast Head Reef, Capricorn Group, Queensland, part II''. Proceedings of the Linnean Society of New South Wales 32: 476-513, pls 16-21 * Oliver, W.R.B. 1915. ''The Mollusca of the Kermadec Islands''. Transactions of the New Zealand Institute 47: 509-568 * Demond, J. 1957. ''Micronesian reef associated gastropods.'' Pacific Science 11(3): 275-341, fig. 2, pl. 1. * MacNeil, F.S. 1960. ''Tertiary and Quaternary Gastropoda of Okinawa''. United States Geological Survey Professional Papers 339: i-iv, 1-148, 19 pls * Ladd, H.S. 1966. ''Chitons and gastropods (Haliotidae through Adeorbidae) from the western Pacific Islands''. United States Geological Survey Professional Papers 531: 1-98 16 pls * Salvat, B. & Rives, C. 1975. ''Coquillages de Polynésie''. Tahiti : Papeete les editions du pacifique, pp. 1–391 * Tantanasiriwong, R. 1978. ''An illustrated checklist of marine shelled gastropods from Phuket Island, adjacent mainland and offshore islands, Western Peninsula, Thailand.'' Phuket Marine Biological Center, Research Bulletin 21: 1-22, 259 figs * Cernohorsky, W.O. 1978. ''Tropical Pacific marine shells''. Sydney : Pacific Publications 352 pp., 68 pls. * Wells, F.E. & Bryce, C.W. 1986. ''Seashells of Western Australia.'' Perth : Western Australian Museum 207 pp. * Wilson, B. 1993. ''Australian Marine Shells. Prosobranch Gastropods''. Kallaroo, Western Australia : Odyssey Publishing Vol. 1 408 pp. * Herbert D.G. (1996) ''A critical review of the trochoidean types in the Muséum d'Histoire naturelle, Bordeaux (Mollusca, Gastropoda).'' Bulletin du Muséum national d'Histoire naturelle, Paris, ser. 4, 18 (A, 3-4): 409-445.

External links

To World Register of Marine Species
* {{Taxonbar, from=Q28959959 calcaratus Gastropods described in 1874