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Conus glans (Hwass in Bruguiere, 1792)
Conus tenuistriatus (Sowerby II, 1857)
Description: Moderately small to moderately large, moderately light to moderately solid. Last whorl usually cylindrical, sometimes ovate, ventricosely conical or conoid-cylindrical; outline straight and parallel-sided adapically to uniformly convex; left side concave at base. Shoulder indistinct to rounded. Spire of moderate height to high, outline convex. Larval shell paucispiral in Sri Lanka (Kohn, 1961 b), of about 2.5 whorls in Philippines specimens, and of 3 or more whorls in specimens from Samoa; maximum diameter 0.6-0.7 mm. First 4-7 postnuclear whorls tuberculate. Teleoconch sutural ramps flat to slightly convex, with 0-1 increasing to 3-7 spiral grooves and often granulose strong ribs between; spiral sculpture sometimes very weak on last ramps. Last whorl with distinct, often granulose, closely spaced spiral ribs from base to shoulder.
Ground colour white to pale blue, suffused with blue or violet. Last whorl variably encircled with 2-3 bluish-brown bands, leaving light zones of different shades of grey, blue, violet or brown, occasionally overlaid with brown or blue axial streaks. Base usually dark violet. Larval shell and first 4-5 postnuclear sutural ramps pink to orange. Aperture light blue behind a violet marginal zone.
Represented in the fossil collections by a single shell collected from the cliff at Houma on Tongatapu, Tonga, about 35 feet (10.6 m) above sea level. The specimen, B. P. Bishop Mus. no. 202938, measures: length 31.4 mm, diameter 12.9 mm. The species lives today throughout the tropical Indo-Pacific. According to Vlerk (1931, p. 213), the species has also been reported from post-Tertiary beds in Celebes (Sulawesi) (1).
C. glans is the most similar species; specimens are often difficult to distinguish. On the sutural ramps, C. glans has usually strong spiral grooves separated by granulose ribs rather than weak spiral grooves or striae as in C. tenuistriatus. C. glans also has a generally cylindrical last whorl (PMD 0.66-0.84) with stronger, somewhat less closely spaced spiral ribs (2).
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Bibliografia
Consultata
