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Taxon profile

species

Alvania micropilosa S. Gofas, 2007

kingdom Animalia - animals »  phylum Mollusca - mollusks »  class Gastropoda - gastropods »  order Littorinimorpha »  family Rissoidae »  genus Alvania

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Alvania micropilosa

Author: Gofas, S.

Description

Shell with a moderately high spire, solid, up to 2.8 x 1.9 mm. Protoconch of 1.5 convex whorls; surface of larval whorls with six to seven fine spiral threads, with broad interspaces bearing minute granulations. Teleoconch of 3.0-3.75 whorls, with a strong sculpture of elevated, widely separated axial ribs, and spiral cords forming knobs at their intersection with the axial sculpture. Ribs ca 14-16 on the penultimate whorl, with adapical termination not prominent along the suture, extending quite far on the abapical part of the body whorl where they very gradually fade out; ribs on body whorl remaining constant in spacing and size where approaching the outer lip. Spiral cords three to four on spire whorls, the abapical one stronger and separated from the suture by a broader interspace; eight on the body whorl. Spiral microsculpture of indistinct threads, on which can be seen some tiny periostracal hairs. Outer lip orthocline or very slightly prosocline, bordered with a thick rim overrun by the spiral sculpture; smooth inside. Inner lip thick and appressed to the preceding whorl. Shell colour entirely white, a few shells with a very pale brownish blotch adapically on the external surface behind the outer lip. Operculum thin, paucispiral, with eccentric nucleus.
Gofas S. (2007). Rissoidae (Mollusca: Gastropoda) from northeast Atlantic seamounts.

Interchangeable taxa

This species resembles Alvania cimicoides in some shell features, with a broad channel between the suture and a cord of the preceding whorl; it differs nevertheless in having a paucispiral protoconch and a nearly colourless shell. The periostracal hairs are characteristic and were not seen on any of the other species (including A. cimicoides) examined at the same magnifications.
Gofas S. (2007). Rissoidae (Mollusca: Gastropoda) from northeast Atlantic seamounts.

Distribution

East Atlantic Sea Mounts
Gofas S. (2007). Rissoidae (Mollusca: Gastropoda) from northeast Atlantic seamounts. This is the commonest rissoid species on Meteor, whereas it is present but extremely rare on Hyeres and Irving seamounts.
Author: Jan Delsing

Similar species

Alvania cimicoides (Forbes, 1844)

Links and literature

EN Galli C.: WMSDB - Wolrdwide Mollusc Species Data Base July 10, 2013 [http://www.bagniliggia.it/WMSD/WMSDhome....] [as Alvania micropilosa Gofas, 2007]
Data retrieved on: 22 November 2013

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