| 词条 | Gibbula beckeri |
| 释义 |
| taxon = Gibbula beckeri | image = | image_caption = | authority = G.B. Sowerby III, 1901 | synonyms_ref = | synonyms = | display_parents = 3 }}Gibbula beckeri is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.[1] DescriptionThe size of the shell attains 8 mm. The shell consists of the protoconch nucleus plus 4 whorls. The profile is rather strongly convex in the upper half of the whorl. There are spiral lirae 2 on 2nd and 3rd whorls, 3 on 4th whorl. These are broad and low, scarcely projecting above the profile, defined by impressed striae, the 3rd being peripheral and feebly carinate; an additional stria (or 2) between 1st and 2nd lirae, and 2-3 between 2nd and 3rd. Sometimes (as in a cotype) only 1 (midwhorl) lira on 2nd and 3rd whorls, but the peripheral one comes into view on 4th whorl. On the base of the shell there is usually a marginal lira and 7-8 weaker lirae, variable. The umbilicus is not completely closed in the largest shells. The growth lines are distinct. The colour of the shell is grey or violaceous-grey with white or pale spots, radiating streaks, and/or zigzag marks. Very young shells (up to 2–3 mm. diam.) are uniformly violaceous. One specimen is yellowish with darker brown radiating patches forming a band below the suture, similar dark patches on the peripheral lira, between these two bands brown zigzags. Two specimens have red-brown radiating streaks on an emerald-green ground colour on 3rd and 4th whorls, streaks extending on to peripheral lira (cf. capensis). The base of the shell contains grey lirae,or is faintly streaked and spotted.[2] DistributionThis species occurs in the Atlantic Ocean from Namibia to Port Alfred, South Africa References1. ^{{WRMS species|225131|Gibbula beckeri G.B. Sowerby III, 1901||1 May 2010}} 2. ^[https://archive.org/details/annalsofsoutha4719637sout Barnard K.H., Contributions to the knowledge of South African marine Mollusca; Annals of The South African Museum vol. 47; 1963]
External links{{Use dmy dates|date=January 2011}}{{Taxonbar|from=Q5558996}}{{DEFAULTSORT:Gibbula Beckeri}} 2 : Gibbula|Gastropods described in 1901 |
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