Hippopus hippopus   (Linnaeus,  1758) (Clam)
Organism information awaits expert curation
Class: Bivalvia

Image copyrights: California Academy of Sciences

Size: Maximum shell length 40 cm, commonly to 20 cm.

Color: Outside of shell off-white, with yellowish orange suffusion and with reddish blotches arranged in irregular concentric bands. Interior porcelaneous white, frequently flushed with yellowish orange on ventral margin. Dorsally exposed mantle area of living specimens is yellowish brown, dull green or grey.

Shell is very thick and heavy, medium to rather large sized, globose in shape and triangularly ovate to sub rhomboidal in outline. Umbones are strongly coiled, at about mid-length or somewhat posterior. Posteroventral margin of valves are without a well-defined byssal orifice, bordered by interlocking crenulations which become stronger posteriorly. Dorsal free margin of shell is irregularly arched and roughly triangular in shape, more protruding at about mid-length, sloping and slightly depressed anteriorly and posteriorly. Both ends narrowly rounded, the anterior one produced. Posteroventral slope more or less strongly concave, bordered by a marked radial angulation. Surface of small specimens (less than 20 cm in length) is moderately rough with prominent, conspicuously ribbed radial folds. Each valve with 9 to 13 or 14 large, rib-like folds and many low radial riblets throughout, crossed by fine, wavy concentric lines of growth. Radial riblets are unequal in size and strength, often with short, prickly, semitubular spines. Inhalent (posterior) siphonal opening is without tentacles.

Synonym (s)
Hippopus porcellanus Rosewater, 1982
Hippopus maculatus Lamarck, 1801
Chama hippopus Linnaeus, 1758
Hippopus equinus Morch, 1853
Tridachnes ungula Roding, 1798
Chama asinus Barbut, 1788

Common Name (s)
• Horses Hoof (English)
Economic Importance and Threats
Importance:  Commercial
(Collected for food. The shell is commonly used in the shellcraft industry.)

Habitat:  Reef Associated, Sandy


• Andaman and Nicobar Islands, Andaman Islands INDIA
• Andaman and Nicobar Islands, Nicobar INDIA
• Andaman and Nicobar Islands, Trinket Island INDIA

Literature Source(s)
  • Poutiers, JM (1998) Bivalves FAO species identification guide for fishery purposes. The living marine resources of the western central Pacific. Volume 1: Seaweeds, corals, bivalves and gastropods FAO, Rome 1 686 pp Available at - http://www.fao.org/docrep/009/w7191e/w7191e00.htm
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at - http://www.marinespecies.org
  • California academy of sciences: Research Available at - http://research.calacademy.org/research/
  • Appukuttan, KK (1996) Marine molluscs and their conservation Marine Biodiversity Conservation And Management CMFRI, Cochin 66-79 Available at - http://eprints.cmfri.org.in/4097/1/Article_6.pdf
  • Subba Rao, NV and Dey, A (2000) Catalogue of marine molluscs of Andaman and Nicobar Islands Occasional paper no 187 Records of the Zoological Survey of India ZSI 1-323 Available at - NCL, Pune

Page last updated on:2012-07-25

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