Английская Википедия:Alvania jeffreysi
Шаблон:Short description Шаблон:Speciesbox
Alvania jeffreysi is a species of minute sea snail, a marine gastropod mollusk or micromollusk in the family Rissoidae.[1]
Distribution
This marine species occurs off Southeast Greenland;off the Shetland Islands; in the Western Mediterranean Sea and in the White Sea, Russia.
Description
The length of the shell varies between 2.3 mm and 4 mm.
The species was described from a specimen found in sand dredged north of Unst, Shetland Islands, Scotland from a depth of Шаблон:Convert. It was named in honour of conchologist and malacologist John Gwyn Jeffreys.
(Original description) The white shell is conical, moderately strong, somewhat glossy and semi-transparent. It contains 5-6 whorls, sloping from the suture to the second ridge, and well rounded thence to the lower suture. The body whorl exceeds half the length of the shell, and is iquely rounded at the base.
Sculpture: on the penultimate whorl there are four slender but well-defined spiral ridges, the lower three of which arc stronger than the highest one, which is on the upper slope of the whorl. The ridges are crossed by about twenty-eight perpendicular ribs, not so much elevated nor nearly as strong as the ridges.They form with them square cancellations, the intersections of the ridges and ribs being scarcely raised, but slightly nodulous. The apical whorls are marked with spiral rows of close angular punctures. In each succeeding row the punctures lie below the ridges separating those of the preceding row. The base of the lowest whorl has 5-7 spiral ridges, for the most part uncrossed by the ribs, which generally terminate at the line of the upper part of the aperture.
The suture deeply defined and somewhat excavated. The aperture is roundish oval. The outer lip is smooth inside, and strengthened outside by a broad and strong rib. The inner lip is smooth and reflected on the columella, making the peristome continuous. The umbilical chink is very small. [2]
Habitat
Minimum recorded depth is 264 m.[3] Maximum recorded depth is 264 m.[3]
References
- Waller E. (1864). On a new British species of Rissoa. Annals and Magazine of Natural History. ser. 3, 14: 136-138
- Gofas, S.; Le Renard, J.; Bouchet, P. (2001). Mollusca. in: Costello, M.J. et al. (eds), European Register of Marine Species: a check-list of the marine species in Europe and a bibliography of guides to their identification. Patrimoines Naturels. 50: 180-213
- Gofas, S.; Warén A. (1982). Taxonomie de quelque espèces du genre Alvania (Mollusca, Gastropoda) des côtes ibériques et marocaines. Bollettino Malacologico. 18(1-4): 1-16
- Шаблон:Cite webШаблон:Dead linkШаблон:Cbignore
- ↑ Шаблон:WRMS species
- ↑ Шаблон:Cite journalШаблон:Source-attribution
- ↑ 3,0 3,1 Welch J. J. (2010). "The "Island Rule" and Deep-Sea Gastropods: Re-Examining the Evidence". PLoS ONE 5(1): e8776. Шаблон:Doi.
