Donax (bivalve)

Donax (bivalve)
Donax is a genus of small, edible saltwater clams, marine bivalve molluscs. The genus is sometimes known as bean clams or wedge shells; however, Donax species have numerous different common names in different parts of the world. In the southeastern U.S. they are known as "coquina", a word that is also used for the hard limestone concretions of their shells and those of other marine organisms.
Ecology
Species of Donax live, sometimes in high concentrations, vertically aligned in the sand on exposed beaches, on tropical and temperate coasts worldwide. When the waves wash these small clams out of the sand, they can dig back in again quite rapidly. They are filter feeders. Some species, such as Donax variabilis, migrate vertically and horizontally with changes in the tides. These coquina clams are found extensively on the east coast beaches of Trinidad (Mayaro) and widely available in Venezuela. They are called "Chip Chip" in Trinidad & Tobago and "Chipi Chipi" in Venezuela.
Species
Species within the genus Donax include:
Donax asper Hanley 1845
Donax assimilis Hanley, 1845
Donax baliregteri Huber, 2012
Donax bertini Pilsbry, 1901
Donax bipartitus Sowerby III, 1892
Donax brazieri Smith, 1892
Donax bruneirufi Huber, 2012
Donax burnupi Sowerby III, 1894
Donax caelatus Carpenter, 1857
Donax californicus Conrad, 1837
Donax carinatus Hanley, 1843
Donax clathratus Reeve, 1855
Donax culter Hanley, 1845
Donax cuneatus Linnaeus, 1758
Donax denticulatus Linnaeus, 1758
Donax dentifer Hanley, 1843
Donax ecuadorianus Olsson, 1961
Donax erythraeensis Bertin, 1881
Donax faba Gmelin, 1791
Donax fossor Say, 1822 - was thought at one time to be a northern form of D. variabilis
Donax francisensis (Cotton & Godfrey, 1938)
Donax gemmula Morrison, 1971
Donax gouldii Dall, 1921 - The bean clam, aka Donax gracilis Hanley 1845
Donax hanleyanus (Philippi, 1847)
Donax kindermanni (Philippi, 1847)
Donax lubricus Hanley, 1845
Donax madagascariensis Wood, 1828
Donax nitidus Deshayes, 1855
Donax obesulus Reeve 1854
Donax obesus d'Orbigny, 1845
Donax oweni Hanley, 1843
Donax paxillus Reeve, 1854
Donax punctatostriatus Hanley, 1843
Donax rothi Coan, 1983
Donax semistriatus Poli, 1795
Donax serra Röding, 1798
Donax simplex Sowerby III, 1897
Donax sordidus Hanley, 1845
Donax striatus Linnaeus, 1767
Donax texasianus Philippi, 1847
Donax townsendi Sowerby III, 1894
Donax transversus Sowerby I, 1825
Donax trunculus Linnaeus, 1758 - Locally known as tellin in French, tellina or telline in Italian, coquina in Spanish and conquilha or cadelinha in Portuguese.
Donax variabilis Say, 1822 - Known in Florida under the Spanish word "coquina", is the common and colorful Donax species of the southern Atlantic and Gulf shores from Virginia to the Caribbean. This species is locally abundant on beaches with fine sand from the mid-Atlantic coast to Texas.
Donax variegatus (Gmelin, 1791)
Donax vellicatus Reeve, 1855
Donax veneriformis Lamarck, 1818
Donax veruinus Hanley, 1913
Donax vittatus (da Costa, 1778)
The empty small (15 to 25 mm) shells of Donax variabilis and Donax fossor may be found washed up on the beach, especially at low tide. The living animals can often be seen where the waves wash the sand around in the shallowest part of the littoral zone as the tidal level changes. These clams can use the action of waves to move themselves up and down the beach, quickly burrowing into a new location before they can be swept away (the so-called "dance of the coquina").
References
Wildlife of Sydney - Fact File - Pipi, Goolwa Cockle, Surf Clam Fact File
Further reading
The Nautilus, On the species of Donax of Eastern North America, March 1892, pp. 125-126
Wayne A. O'Connor & Stephan J. O'Connor, "Early ontogeny of the pipi, Donax (Plebidonax) deltoides (Donacidae; Bivalvia)"; Molluscan Research 31(1): 53–56;
Donacidae
Bivalve genera