Donax (bivalve)

{{short description|Genus of molluscs}}{{Ntbcw|Donax (plant)}}{{Automatic taxobox

| image = Coquina variation3.jpg

| image_caption = A group of shells of Donax variabilis showing color variation

| taxon = Donax (bivalve)

| authority = Linnaeus, 1758

| subdivision_ranks = Species

| subdivision = See text

| synonyms_ref =

| synonyms = *Capsella Gray, 1851

Grammatodonax Dall, 1900

}}

Donax is a genus of small, edible saltwater clams, marine bivalve molluscs with highly variable color patterns. The genus is sometimes known as bean clams or wedge shells; however, Donax species have 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 in the swash zone, 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 phytoplankton filter feeders. They are an import source of food for crabs, fish and shorebirds. They are sensitive to environmental conditions and are considered an indicator of beach habitat health.{{Cite web |title=Coquina Clams |url=https://myfwc.com/research/saltwater/mollusc/other-molluscs/coquina-clams/ |access-date=2024-05-30 |website=Florida Fish And Wildlife Conservation Commission |language=en}} Some species, such as Donax variabilis, migrate vertically and horizontally with changes in the tides. The genus enjoys a global distribution.{{Cite web |title=Donax Linnaeus, 1758 |url=https://www.gbif.org/species/2287060 |access-date=2024-05-30 |website=www.gbif.org |language=en}} These coquina clams are found extensively on the east coast beaches of Trinidad (Mayaro) and widely available in Venezuela.

Human use

Donax is an edible mollusk that has been consumed since pre-historic times and is still consumed today. Numerous recipes for coquina soup have been published. Recreational foragers should follow seafood safety guidelines and shellfish harvesting restrictions, and should be aware of any harmful algal blooms that may contaminate shellfish with biotoxins. In some parts of the world Donax clams are still gathered by indigenous people as an important subsistence food.{{Cite journal |last1=Sordo |first1=Laura |last2=Vasconcelos |first2=Paulo |last3=Piló |first3=David |last4=Carvalho |first4=André N. |last5=Pereira |first5=Fábio |last6=Gaspar |first6=Miguel B. |date=September 2023 |title=Recreational harvesting of the wedge clam (Donax trunculus) in southern Portugal: Characterization of the activity based on harvesters' perception and local ecological knowledge |url=https://doi.org/10.1016/j.marpol.2023.105694 |journal=Marine Policy |volume=155 |pages=105694 |doi=10.1016/j.marpol.2023.105694 |bibcode=2023MarPo.15505694S |issn=0308-597X|hdl=10400.1/20089 |hdl-access=free }}

Species

File:Donax cuneatus Linné, 1758 (3263505910) (2).jpg shell]]

Species within the genus Donax include:

Donax asper Hanley 1845[http://eol.org/pages/2942466/overview eol Encyclopedia of Life]
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
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

[https://web.archive.org/web/20080601003314/http://www.faunanet.gov.au/wos/factfile.cfm?uid=48D46A2E-66F3-4A3A-86DCB810C6FBD9E8 Wildlife of Sydney - Fact File - Pipi, Goolwa Cockle, Surf Clam Fact File]

Donax (bivalve)

Ecology

Human use

Species

References

Further reading