''Tectus pyramis'', common name the pyram top shell, 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 Turbinidae, the turban snails.

Description

The size of the shell varies between 45 mm and 105 mm. The imperforate, solid, thick shell has a strictly conical shape. The spire is more or less attenuated above. The apex is acute. The color of the shell is yellowish or grayish, more or less mottled and marbled with green or brown, the base is white, green or brown. The shell contains 12–14

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. The upper ones are slightly extended outwards and plicate, tuberculate or undulating at the sutures. The folds or tubercles are obsolete on the lower whorls. The upper whorls are encircled with one or two spiral series of small tubercles or beads, which are increased to about five series on the middle whorls. 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 ...

is beaded, but smoother than the preceding, or radiately finely wrinkled, or nearly smooth, angulate at the periphery. The base of the shell is flat, concentrically lirate, the ribs smooth, wide, separated by shallow grooves, obsolete toward the outer margin. The aperture is transverse, very oblique, subtriangular, the outer wall grooved within. The basal margin is straight, not concave in the middle, deeply notched at its junction with the columella. The sculpture inside shows revolving acute plicae, corresponding to the lirae which revolve around the central area outside. The columella is very short, with a very strong acutely carinated spiral fold.Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
(described as ''Trochus obeliscus'')

Distribution

This species occurs in the Indian Ocean off Chagos, the Mascarene Basin and in the Western Pacific Ocean and off Indonesia to

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

Fiji Fiji ( , ,; fj, Viti, ; Fiji Hindi: फ़िजी, ''Fijī''), officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists ...

and Australia ( Queensland, Western Australia, Northern Territories, Tasmania)

References

* Gmelin, J.F. & Linnaeus, C. 1791. ''Caroli a Linné Systema Naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentis, synonymis, locis''. Editio decima tertia aucta, reformata Lipsiae : G.E. Beer * Lamarck, J.B. 1822. ''Histoire naturelle des Animaux sans Vertèbres'' Paris : J.B. Lamarck Vol. 7 pp. 711 pp * Solem, George Alan (1953), ''Marine and fresh-water mollusks of the Solomon Islands''; Fieldiana Zoology v.34, no.22 * Drivas, J. & M. Jay (1988). ''Coquillages de La Réunion et de l'île Maurice''

External links

*
Atlas of Living Australia: ''Tectus (Tectus) pyramis''
{{DEFAULTSORT:Tectus Pyramis

pyramis Pyramis Group is a Greek multinational kitchen products corporation, headquartered in Thessaloniki, Greece. History The Decade of Establishment: 1959–1968 In 1959, Alexandros Bakatselos, Chairman of Pyramis, opened a small workshop specialis ...

Gastropods described in 1778 Marine gastropods