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Taxon profile

species

Clanculus villanus (Philippi, 1846)

kingdom Animalia - animals »  phylum Mollusca - mollusks »  class Gastropoda - gastropods »  order Trochida »  family Trochidae - top-shells »  genus Clanculus

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Clanculus villanus

Author: Jan Delsing

Clanculus villanus

Author: Jan Delsing

Clanculus villanus

Author: Rubio & Rolan

Clanculus villanus

Author: Rubio & Rolan

Clanculus villanus

Author: Ardovini, R. & Cossignani, T.

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Description

Shell very solid, large (D > 18 mm in the adult individuals) and little depressed (H/D = 0.85-0.95), trochoid, conical spire of about 7 whorls, separated by a shallow suture. Base convex with a deep narrow umbilicus. Protoconch of barely 3/-1 whorl and diameter of about 206 mu, white, totally smooth; a strong sinuous lip marks the end of the protoconch. Teleoconch with a whitish first whorl, which shows two smooth spiral cords; in the subsequent whorl, there are three cords that become nodulose and with alternating red or dark brown color. Fourth and 5th whorls have 5 spiral cords and 6 in the subsequent ones, all them nodulose except the outermost which is smooth. The nodules are rectangular and very close together, of different size, and become smaller towards the periphery; the subsutural cord has stronger nodules. Spaces between cords are wider, showing 1-2 spiral threads in each one. Very fine oblique growth striae cover the entire surface of the shell. Base with 8-9 flat smooth cords, lacking spiral threads between them, with nodules hardly noticeable in juveniles. Umbilicus white, umbilical margin crenulated with 3-4 strong denticles, with a callus partially covering its inner part. Aperture trapezoidal, a little rounded, pearly inside; parietal region with a slight callus, weak parietal wrinkles; no parietal or anal tooth. Outer lip with sharp border, with some spiral wrinkles inside, and no internal denticles on its border. Columella sloped and slightly curved, with 4 simple teeth, one of them triangular on the upper part, two smaller ones on its middle part and another, stronger, at the base. The inner lip enlarged where the columella bears three denticles, the largest closest to the columella. The shell color is dark olivaceous-gray, sometimes reddish, alternating this color on the cords with small white and brown or black areas. On the last whorl, the spaces between the cords close to the periphery and those on the base, have a lighter color, making the variation of color on the cords more evident.
Dimensions; the largest specimens studied were 19 mm high x 21 mm maximum diameter, not depressed (H/D = 0.84-1.00), from Takoradi (Ghana) and Rio Muni. The size mentioned by PlLSBRY (1889) for this species was 22 mm high and 22 mm diameter.
Rubio, F. & Rolán, E., 2002. Revision of the Genus Clanculus (Gastropoda: Trochidae) in the Eastern Atlantic.

Distribution

Its known distribution area is limited to the countries of the Gulf of Guinea, excluding Sao Tome and Principe Is., from where we have no material nor bibliographic references. We have nor collected this species from Annobon, in spite of the material so labeled in MNCN, which may be an error. Our material came from Ghana, Byoko, and Equatorial Guinea, which is in agreement with the distribution given for this species by FlSHER (1887: from Gulf of Guinea to Benguela, Angola), PILSBRY (1889: Guinea, Costa de Oro - actually Ghana - and Gabon), BERNARD (1984: Gabon, in rocky bottom between 0 and 5 m), and PAES DA FRANQA (I960: Mocamedes, Angola).
Author: Jan Delsing

Similar species

Clanculus spadiceus Philippi, 1848

Links and literature

EN Galli C.: WMSDB - Wolrdwide Mollusc Species Data Base July 10, 2013 [http://www.bagniliggia.it/WMSD/WMSDhome....] [as Clanculus villanus Philippi, 1846]
Data retrieved on: 23 November 2013

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