Veneridae

Veneridae
A valve of Venus verrucosa
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Venerida
Superfamily:	Veneroidea
Family:	Veneridae Rafinesque, 1815
Genera
See text

Left valve dentition of the shell of the venerid Mercenaria mercenaria

The Veneridae or venerids, common name: venus clams, are a very large family of minute to large, saltwater clams, marine bivalve molluscs. Over 500 living species of venerid bivalves are known, most of which are edible, and many of which are exploited as food sources.

Many of the most important edible species are commonly known (in the USA) simply as "clams". Venerids make up a significant proportion of the world fishery of edible bivalves. The family includes some species that are important commercially, such as (in the USA) the hard clam or quahog, Mercenaria mercenaria.

Classification

The classification within the family Veneridae has been controversial at least since the 1930s. The most used classification is that of Keen (1969) which recognises 12 subfamilies, listed below. Some common species have been moved between genera (including genera in different subfamilies) because of repeated attempts to bring a more valid organization to the classification or taxonomy of the family, therefore changes in the generic name of species are frequently encountered.

The characters used for classifying this group still tend to be superficial, focusing on external features, especially those of the shell. Venerid clams are characterized as bivalves with an external posterior ligament, usually a well demarcated anterior area known as the lunule, and three interlocking structures (called cardinal teeth) in the top of each valve; several of the subfamilies also have anterior lateral teeth, anterior to the cardinal teeth: one in the left valve, and two (sometimes obscure) in the right valve. The inner lower peripheries of the valves can be finely toothed or smooth.

Description

Venerid bivalve; Wadi Umm Ghudran Formation (Late Cretaceous, early Campanian), near Amman, Jordan

Dentition of venerid bivalve; Wadi Umm Ghudran Formation (Late Cretaceous, early Campanian), near Amman, Jordan

Shell sculpture tends to be primarily concentric, but radial and divaricating ornamentation (see Gafrarium), and rarely spines (Pitar lupanaria for example) occur on some. One small subfamily, the Samarangiinae, is created for a unique and rare clam found in coral reefs with an outer covering of cemented sand or mud that texturally camouflages it while enhancing the thickness of the shell. Several venerid clams have overall shell shapes adapted to their environments. Tivela species, for example, have the triangular outline of the surf clams in other bivalve families, and occur often in surf zones. Some Dosinia species are almost disc-like in shape and reminiscent of lucinid bivalves; both types of circular bivalves tend to burrow relatively deeply into the sediment. Further reclassification is to be expected as the results of current research in molecular systematics on the group appear in the literature.

Venerids have rounded or oval solid shells with the umbones (projections) inturned towards the anterior end. Three or four cardinal teeth are on each valve. The siphons are short and united, except at the tip, and are not very long. The foot is large.

Subfamilies according to Keen (1969)

• Chioninae
• Circinae
• Clementinae
• Cyclininae
• Dosiniinae
• Gemminae
• Meretricinae
• Pitarinae
• Samarangiinae
• Sunettinae
• Tapetinae
• Venerinae

List of genera in the family Veneridae

Extended content

Marcia marmorata Sunetta meroe Agriopoma Dall, 1902 Amiantis Carpenter, 1884 Anomalocardia Schumacher, 1817 Anomalodiscus Dall, 1902 Antigona Schumacher, 1817 Aphrodora Jukes-Browne, 1914 Asaphinoides F. Hodson, 1931 †Atamarcia Marwick, 1927 Austrovenus Finlay,1927 Bassina Jukes-Browne, 1914 Callista Poli, 1791 Callithaca Dall, 1902 Callocardia A. Adams, 1864 Callpita M. Huber, 2010 Chamelea Mörch, 1853 Chione Megerle von Mühlfeld, 1811 †Chionella Cossmann, 1886 Chioneryx Iredale, 1924 Chionista Keen, 1958 Chionopsis Olsson, 1932 Choristodon Jonas, 1844 Circe Schumacher, 1817 Circenita Jousseaume, 1888 Circomphalus Klein, 1853 Clausinella J. E. Gray, 1851 Clementia Gray, 1842 Compsomyax Stewart, 1930 Comus Cox, 1930 Cooperella Carpenter, 1864 Costacallista Palmer, 1927 Costellipitar Habe, 1951 Cryptonema Jukes-Browne, 1914 Cyclina Deshayes, 1850 Cyclinella Dall, 1902 Dorisca Dall, Bartsch & Rehder, 1938 Dosina Gray, 1835 Dosinia Scopoli, 1777 Egesta Conrad, 1845 Eumarcia Iredale, 1924 Eurhomalea Cossmann, 1920 Ezocallista Kira, 1959 †Flaventia Jukes-Browne, 1908 †Frigichione Fletcher, 1938 Gafrarium Röding, 1798 Gemma Deshayes, 1853 Globivenus Coen, 1934 Gomphina Mörch, 1853 Gomphinella Marwick, 1927 Gouldia C. B. Adams, 1847 Gouldiopa Iredale, 1924 Granicorium Hedley, 1906 †Grateloupia [anonymous], 1830 †Hinemoana Marwick, 1927 Humilaria Grant and Gale, 1931 Hyphantosoma Dall, 1902 Hysteroconcha Dall, 1902 Iliochione Olsson, 1961 Irus Schmidt, 1818 Irusella Hertlein and Grant, 1972 Jukesena Iredale, 1915 Katelysia Römer, 1857 †Katherinella Tegland, 1929 Kyrina Jousseaume, 1894 Laevicirce Habe, 1951 Lajonkairia Deshayes, 1854 Lamelliconcha Dall, 1902 Lepidocardia Dall, 1902 Leukoma Römer, 1857 Lioconcha Morch, 1853 Liocyma Dall, 1870 Lirophora Conrad, 1883 Macridiscus Dall, 1902 Macrocallista Meek, 1876 Marcia H. Adams & A. Adams, 1857 †Marwickia Finlay, 1930 Megapitaria Grant & Gale, 1931 Mercenaria Schumacher, 1817 Meretrix Linnaeus, 1758 †Meroena Jukes-Browne, 1908 Microcirce Habe, 1951 Mysia Lamarck, 1818 Notocallista Iredale, 1924 Nutricola Bernard, 1982 †Paleomarcia Fletcher, 1938 Panchione Olsson, 1964 Paphia Born, 1778 Paphonotia Hertlein & Strong, 1948 Parastarte Conrad, 1862 Paratapes Stoliczka, 1870 Parvicirce Cosel, 1995 Pelecyora Dall, 1902 Periglypta Jukes-Browne, 1914 Petricola Lamarck, 1801 Petricolaria Stoliczka, 1870 Pitar Römer, 1857 Pitarenus Rehder & Abbott, 1951 Placamen Iredale, 1925 Polititapes Chiamenti, 1900 Privigna Dall, Bartsch & Rehder, 1938 Protapes Dall, 1902 Protocallithaca Nomura, 1937 Proxichione Iredale, 1929 Psephidia Dall, 1902 Redicirce Iredale, 1924 †Rohea Marwick, 1938 Ruditapes Chiamenti, 1900 Samarangia Dall, 1902 Saxidomus Conrad, 1837 Sunetta Link, 1807 Sunettina Pfeiffer, 1869 Tapes Muhlfeld, 1811 Tawera Marwick, 1927 Timoclea Brown, 1827 Tivela Link, 1807 Transennella Dall, 1883 Transenpitar Fischer-Piette & Testud, 1967 †Turia Marwick, 1927 Turtonia Alder, 1848 Veneriglossa Dall, 1886 [temporary name] Venerupis Lamarck, 1818 Venus Linnaeus, 1758

References

• Keen, A. M. (1969). Superfamily Veneracea. pp. 670–690, in: Leslie Reginald Cox et al., Part N [Bivalvia], Mollusca 6, vols. 1 and 2: xxxvii + 952 pp. Part of Raymond C. Moore, ed., Treatise on Invertebrate Paleontology. Lawrence, Kansas (Geological Society of America & University of Kansas).
• Powell A. W. B., New Zealand Mollusca, William Collins Publishers Ltd, Auckland, New Zealand 1979 ISBN 0-00-216906-1

Gallery

• 
  Dosinia anus from New Zealand, a member of the Dosiniinae
• 
  Austrovenus stutchburyi from New Zealand
• 
  Chamelea striatula
• 
  Irus elegans from New Zealand
• 
  Mercenaria mercenaria
• 
  Pitar lupanaria from Costa Rica
• 
  Venerupis senegalensis

External links

• Taxonomy on the half shell A major project of the Chicago Field Museum of Natural History and the American Museum of Natural History on Venerid classification
• Bibliography of venerid taxonomy
• VENERIDAE - www.chez.com
• ZipCodeZoo