Pyramidella


Pyramidella is a genus of minute to medium-sized sea snails, marine gastropod molluscs in the subfamily Pyramidellinae of the family Pyramidellidae, the pyrams and their allies.
Pyramidella is the type genus of the family Pyramidellidae.

Nomenclature

The generic name Pyramidella Lamarck, 1799, has been validated under the Plenary Powers of the ICZN, Opinion 386. The name Obeliscus Anonymus, 1797 has also been used for this genus, whereas the name Pyramidella was used for the genus now known as Otopleura Fischer, 1885.

General description

The shell has an elongate-conic shape, slightly striated. The many whorls of the teleoconch are usually inflated and regularly increasing. They are longitudinally ribbed or smooth. The semioval aperture is entire, widened at its base and rounded in front..The columella has one to three folds. The sharp outer lip is entire, inferiorly sub-perforated and often plicate within with three transverse folds. The shell is usually larger than in Turbonilla. The thin operculum is horny, ovate, elongated, with very fine elements and oblique folds
and folds oblique. The shell lacks an epidermis.
The shells are generally quite small, of an elegant form, elongated, marked with more or less deep spots. The general color of the body of these mollusca, is of a dull white. The operculum only, and the edge of the mantle are yellowish.
The animal has a head surmounted by broad, rather long tentacles, formed like a pointed horn, and open on the side. The mouth is situated in a flattened, wide, dilated, and quite deeply two-lobed muzzle, separated from the foot by a groove. The respiratory cavity open throughout the whole length of the mantle, bearing on its right margin a long and narrow branchia. The heart has a direction from right to left. The rectum and uterus are attached to each other along the branchiae, and terminate in an ear-shaped gutter, produced by the margin of the mantle. The mucous follicles line the upper wall of the cavity. The foot is round, without a marginal furrow, passing down before in form of an ear-shaped shield, and bearing posteriorly a membranous operculum, with laminas destitute of a spire, which possesses one or two notches to slip upon the folds of the columella.

Species

Species within the genus Pyramidella include:Pyramidella adamsi Carpenter, 1864Pyramidella africana Bartsch, 1915Pyramidella alfredensis Bartsch, 1915Pyramidella ava Bartsch, 1926Pyramidella bairdi Dall & Bartsch, 1909Pyramidella bicolor Menke, 1854Pyramidella camara Bartsch, 1927
;Taxa inquirenda:Pyramidella curtissima Locard, 1897 Pyramidella obeliscus W. H. Turton, 1932Pyramidella suavissima Preston, 1905 Pyramidella sykesi Preston, 1905 Pyramidella tarpeia Bartsch, 1915
;Subgenera and species brought into synonymy:Pyramidella A. Adams, 1860: synonym of Agatha A. Adams, 1860Pyramidella Mörch, 1875: synonym of Longchaeus Mörch, 1875Pyramidella A. Adams, 1860: synonym of Syrnola A. Adams, 1860Pyramidella Dall & Bartsch, 1906: synonym of Tiberia Jeffreys, 1884Pyramidella Dall & Bartsch, 1904: synonym of Longchaeus Mörch, 1875Pyramidella achates : synonym of Longchaeus achates Pyramidella aclis A. Adams, 1853: synonym of Rissosyrnola aclis Pyramidella acus - needle pyram: synonym of Longchaeus acus Pyramidella affinis : synonym of Chrysallida affinis Pyramidella aganea Bartsch, 1915: synonym of Syrnola aganea Pyramidella ambigua Gould, 1849: synonym of Rissoina ambigua Pyramidella aprustica Crema, 1903: synonym of Euparthenia bulinea Pyramidella arenosa Conrad, 1843: synonym of Longchaeus suturalis Pyramidella auricoma Dall, 1889: synonym of Longchaeus auricoma Pyramidella auriscati : synonym of Otopleura auriscati Pyramidella balteata : synonym of Tiberia balteata Pyramidella canaliculata : synonym of Pyramidella insularum Pilsbry, 1922