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Heliacus

Heliacus is a genus of gastropods belonging to the family Architectonicidae.

General characteristics

(Original description in French) The operculum is corneous and conical, increasing in diameter from the apex to the base; its inner side is smooth with a central point; all the rest is composed of spirally coiled lamellae which decrease in diameter and are always fringed at their circumference. The shell is usually higher than the other sundials, with a narrower umbilicus.

(Described as Gyriscus in Latin) The shell is turbinate, conico-turreted, and umbilicate; the apex is blunt, with the tip involuted; the whorls are rounded and transversely girdled; the aperture is subcircular, with the margins sharp and joined by a callus, the columellar lip being reflected. The operculum is corneous (horny), multispiral on the upper part, and provided with a stylet-like process on the lower part.

Distribution

The Heliacus species are typically found in warm-temperate to tropical waters globally, from the intertidal zone down to the subtidal and occasionally deeper.

Species

References

  • SeaLifeBase
  • Powell A. W. B., New Zealand Mollusca, William Collins Publishers Ltd, Auckland, New Zealand 1979
  • Bieler, R. (1987). Die Gattungen der Architectonicidae (Gastropoda: Allogastropoda). Teil 4: Heliacus (Pyrgoheliacus) n. subgen. und Architectonica (Adelphotectonica) n. subgen. Archiv für Molluskenkunde. 117 (4/6): 203-215, pls. 1-2
  • Bieler, R. (1993). Architectonicidae of the Indo-Pacific (Mollusca, Gastropoda). Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg. NF. 30: 1-376

External links