|
|
|
Conus glaucus (Linnaeus, 1758)
Die Unterscheidung dieser Species von C. figulinus LINN. dürfte im fossilen Zustande häufig unmöglich sein, da beider Forn. in allen Einzelheiten übereinstimmt; ein Exemplar der Verbeek'schen Sammlung zeigt aber noch Spuren der für C. glaucus charakteristischen Strichelung, so dass daraufhin seine Bestimmung enfolgen konnte. Ein anderes, ohne Spuren von Färbung, kann nur unter Vorbehalt mit derselben Art vereinigt werden; es zeigt wellige Furchen auf dem Stirnal-schnitte, wie solche auch bei den recenten Vertretern von C. glaucus vorkommen (1).
Zar Unterscheidung von C. Loroisii KIEN, und besonders von dessen fossilen Vorläufern, kann die eiförmige Gestalt des Gehäuses dienen, ferner die abweichende Furchung des Stirnabschnittes, wenn eine solche überhaupt vorhanden ist, und das Fehlen der Spiralgrabe auf dem hinteren Abschnitte der Schlusswindang. Meist wird schon die stärkere, hintere Abstutzung des Gehäuses bei den fossilen Exemplaren von C. Loroisii die Abtrennung ohne Mühe ermöglichen (1).
Das erstgenannte Individuum stammt vom Kampong Odeng am Tji Djarian, Distrikt Palabuan, das zweite, unsichere, von der Ausmündung des Tji Djadjar in den Tji Waringin (1).
Distinguishing this species from C. figulinus Linn. is often impossible in the fossil state, as both forms are identical in every detail; however, one specimen in the Verbeek collection still shows traces of the striations characteristic of C. glaucus, allowing its identification. Another, without any traces of coloration, can only be tentatively grouped with the same species; it shows wavy furrows on the frontal section, such as those also occur in recent representatives of C. glaucus (1).
To distinguish it from C. loroisii Kien, and especially from its fossil predecessors, the egg-shaped form of the shell can be used, as well as the different furrowing of the frontal section, if any is present at all, and the absence of the spiral groove on the posterior section of the terminal whorl. In most cases, the stronger posterior truncation of the shell in fossil specimens of C. loroisii will allow for easy separation (1).
The first individual comes from Kampong Odeng on the Tji Djarian, Palabuan district, the second, uncertain, from the mouth of the Tji Djadjar into the Tji Waringin (1).
|
|
|
Description: Medium-sized to moderately large, moderately solid to moderately heavy. Last whorl ventricosely conical to broadly and ventricosely conical, occasionally slightly pyriform; outline convex adapically, less so toward base; left side my be concave near base. Shoulder subangulate to rounded. Spire low, outline almost straight to concave. Teleoconch sutural ramps slightly convex to slightly concave, with spiral striae. Last whorl with pronounced spiral ribs of varying width at base.
Discussion: C. glaucus differs from C. betulinus and C. suratensis in its smaller size and its distinctive grey rather than yellow or white ground colour. C. suratensis can also be separated by its generally narrower last whorl with spiral ribbons instead of ribs at base. Where both species co-occur, C. betulinus has a coarser pattern. C. glaucus closely resembles some C. loroisii from the Indian Ocean in colour pattern. The latter species is larger (50-120 mm), its ground colour is brownish grey rather than bluish grey, the radial blotches on its sutural ramps are lighter and confluent rather than separate, and the spiral lines on its last whorl consist of longer, more closely spaced markings.
|
|
|
|
Bibliografia.
