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Taxon profile

species

Seguenzia elegans J. G. Jeffreys, 1876

kingdom Animalia - animals »  phylum Mollusca - mollusks »  class Gastropoda - gastropods »  order Seguenziida »  family Seguenziidae »  genus Seguenzia

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Seguenzia elegans

Author: Salvador, R.B. , Cavallari, D.C. & Simone, L.R.L.

Taxon in country check-lists*

Europe: Portugal, North America: Bermuda, South America: Argentina, Brazil

* List of countries might not be complete

Description

Shell small, conical, relatively thin-walled, with stepped spire. Color translucent to nacreous glossy white. Protoconch (-1 whorl) prominent, bulbous, microporous; transition to teleoconch sometimes visible as an orthocline line, but not always well-marked. Teleoconch sculpture (except whorl base) consisting of strong spiral cords, with well-marked axial threads and very fine spiral threads between cord and suture; spire whorls bearing two visible spiral cords: a weaker subsutural one, and a stronger supramedian that produces a distinct keel; a third strong cord (though weaker than the supramedian) can be observed emerging below the abapical suture. Distance between axial riblets roughly equal to three times rib width; axial threads prosocline above median keel and opisthocline below it, creating a continuous sigmoid pattern. Whorl base sculptured by 8-10 spiral cords; axial threads between cords, becoming fainter toward umbilicus. Whorls slightly concave between spiral cords, but with overall rounded profile. Suture obscured by subsutural spiral cord. Aperture rounded quadrangular, with well-marked callus, strong columellar tooth, and three labral sinuses: a deep subsutural sinus; a shallow sinus in peripheral part of basal region of aperture; and a very shallow sinus in palatal region of aperture, corresponding to the umbilical carina. Umbilicus narrow, deep, with well-marked (stronger than adjacent spiral cords) but smooth edge. Measurements (in mm): 5,75-6,75 whorls, H = 2.7 ±0.27; D = 2.50 ±0.18; h= 1.37 ± 0.18; d = 1.02 ±0.14.
Salvador, R.B. , Cavallari, D.C. & Simone, L.R.L., 2014, Seguenziidae (Gastropoda Vetigastropoda) from SE Brazil collected by the Marion Dufresne (MD55) expedition

Interchangeable taxa

Specimens of S. elegans can be easily distinguished by their overall roundish profile and numerous and closely-packed spiral cords on the basal portion of the whorls. The species has an amphi-Atlantic distribution, but this is the first record from southern Brazilian waters.
Salvador, R.B. , Cavallari, D.C. & Simone, L.R.L., 2014, Seguenziidae (Gastropoda Vetigastropoda) from SE Brazil collected by the Marion Dufresne (MD55) expedition

Distribution

North Atlantic: Bay of Biscay, off Portugal (Jeffreys 1885); off Bermuda (Clarke 1959); off Yucatan, Mexico (Quinn 1983b). South Atlantic: Cape Basin and Argentine Basin (Clarke 1961). New occurrence: Southeastern Brazil, Espirito Santo, from 1540 to 3450 m depths.
Salvador, R.B. , Cavallari, D.C. & Simone, L.R.L., 2014, Seguenziidae (Gastropoda Vetigastropoda) from SE Brazil collected by the Marion Dufresne (MD55) expedition
Author: Jan Delsing

Links and literature

EN Galli C.: WMSDB - Wolrdwide Mollusc Species Data Base July 10, 2013 [http://www.bagniliggia.it/WMSD/WMSDhome....] [as Seguenzia elegans Jeffreys, 1876]
Data retrieved on: 22 November 2013

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