Alvania tomentosa (Pallary, 1920)
NW. Spain to NW. Morocco, to W. Mediterranean.
Detritus feeder in the low circalittoral and on the continental shelf. Original taxon: Rissoa tomentosa.
 
Synonym: altenai, van Aartsen, Menkhorst & Gittenberger, who write: « Shell small and relatively slender, with about 1½ embryonic and 2½ to 3 teleoconch whorls, which are rather convex and shouldered adapically. There are four spirals on the initial whorls; the last whorl has three to four additional spirals. Many ( 15-20) longitudinal ribs cross the spirals; slight knobs are seen at the crossing points. […] Suture clearly visible, not very much inclined. Last whorl occupying about two-thirds of the total height of the shell. Aperture slightly oval, its longer axis, in the direction of the spire, equals about 0.4 of the total height of the shell. Outer lip curved and opisthocline, thickened outside by a strengthened rib; inside smooth. Inner lip united with the outer lip. » – van Aartsen, Menkhorst & Gittenberger: “The marine mollusca of the Bay of Algeciras, Spain, with general notes on Mitrella, Marginellidae and Turridae”, Basteria suppl. 2, p.23-24.

200-300m deep, Gibraltar Strait. 1,7mm.
Protoconch paucispiral, often slightly coloured.
The shell differs from those of fischeri and zetlandica by a more slender shape and by less spiny knobs.

— back to Rissoidae —