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MarBEF Data System |
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MolluscaBase taxon details
original description
Gofas S. (2007). Rissoidae (Mollusca: Gastropoda) from northeast Atlantic seamounts. <i>Journal of Natural History 41(13–16)</i>: 779–885
page(s): 801-803 [details]
From editor or global species database
Biology Type of larval development: direct (non planktotrophic) denoted by paucispiral protoconch. [details]
Diagnosis Shell 3.0- 3.3 mm high, with protoconch of 1.5 whorl and teleoconch of 3.75 to 4 whorls. Protoconch with 6-7 fine spiral threads; teleoconch with a strong sculpture of elevated, widely separated axial ribs fading out adapically where they meet the suture, and spiral cords forming knobs at their intersection with the axial sculpture. Spire whorls with one prominent spiral cord, situated at about two-thirds abapically, separated from the suture by a broadly channelled interspace, and at one-third abapically a faint indication of another cord. Spiral microsculpture extremely faint and appreciable only under SEM, consisting of minute pits forming irregularly interrupted spiral lines. Outer lip bordered with a thick rim on which the spiral sculpture is much attenuated; slightly thickened and bearing a few small denticles inside. Shell translucent, penultimate spire whorl with one spiral series of very pale brown blotches on the ribs, and body whorl with two such series of blotches, more intense where they arrive behind the outer lip.
This species resembles Alvania zoderi Hoenselaar and Goud, 1998, from the bathyal slopes of the Azores, in having rather smooth ribs on the spire whorls and a strong cord overhanging the suture. The protoconchs are however quite different, rather conical and smooth with a faint keel in A. zoderi, bulging and ornamented with spiral threads in A. hyerensis; neither the pitted microsculpture nor a colour pattern were mentioned by Hoenselaar and Goud (1998).
There is a superficial resemblance to the sympatric A. elenae Gofas, 2007 in shell size, shape and colour, but the two species are easily separated by the smoother ribs on the spire of A. hyerensis and, under the scanning electron microscope, by the pitted microsculpture unusual in Alvania species. [details]
Distribution Hyères seamount, endemic, very common in 310-750 m [details]
Type locality Hyères seamount (31º23.2'N, 28º53.5'W, 480 m). [details]
From editor or global species database
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