Nucula is a genus of very small saltwater clams. They are part of the family Nuculidae.
Fossil records This genus is very ancient. Fossils are known from the Arenig to the Quaternary (age range: from 478.6 to 0.0 million years ago). Fossils are found in the marine strata all over the world.
Description Shells of species within this genus can reach a size of about . They are equivalve, symmetrical, approximately triangular. The surface has fine concentric growth lines. These clams live in the muddy sand close to the sediment surface at a depth of 20 to 200 meters.Marine Microfauna Genus Trait Handbook
Species Nowadays there are still many species of this genus, which have had virtually no change in the course of time. Species within the genus Nucula include:WoRMS
Nucula annulata Hampson, 1971 Nucula atacellana Schenck, 1939 - cancellate nutclam Nucula austrobenthalis Dell, 1990 Nucula beachportensis Verco, 1907 Nucula benguelana (A. H. Clarke, 1961) Nucula brasiliana Esteves, 1984 Nucula calcicola Moore, 1977 - reef nutclam Nucula callicredemna Dall, 1890 Nucula cancellata Meek & Hayden, 1856 Nucula cardara Dall, 1916 Nucula carlottensis Dall, 1897 - Charlotte nutclam Nucula certisinus Finlay, 1930 Nucula chrysocome Nucula consentanea Melvill & Standen, 1907 Nucula covra Bergmans, 1978 Nucula crassicostata E. A. Smith, 1872 Nucula crassidens Nicklès, 1955 Nucula crenulata A. Adams, 1856 - crenulate nutclam Nucula crystallina Poppe, Tagaro & Stahlschmidt, 2015 Nucula culebrensis E. A. Smith, 1885 Nucula cymella Dall, 1886 Nucula darella Dall, 1916 Nucula declivis Hinds, 1843 Nucula delphinodonta Mighels & C. B. Adams, 1842 - dolphintooth nutclam Nucula distincta Turton, 1932 Nucula donaciformis E. A. Smith, 1895 Nucula dorsocrenata (Habe, 1977) Nucula dunedinensis Finlay, 1928 Nucula exigua G. B. Sowerby I, 1833 - iridescent nutclam, short nutclam Nucula exodonta Prashad, 1932 Nucula faba Xu, 1999 Nucula falklandica Preston, 1912 Nucula fernandensis Villarroel, 1971 Nucula fernandinae Dall, 1927 Nucula gallinacea Finlay, 1930 Nucula granulosa Verrill, 1884 Nucula groenlandica Posselt, 1898 - Greenland nutclam Nucula hanleyi Winckworth, 1931 Nucula hartvigiana Dohrn, 1864 Nucula hawaiensis Pilsbry, 1921 Nucula inconspicua H. Adams, 1871 Nucula insignis (Hayami & Kase, 1993) Nucula interflucta Marincovich, 1973 Nucula iphigenia Dall, 1896 Nucula irregularis G. B. Sowerby III, 1904 Nucula izushotoensis (Okutani, 1966) Nucula kanaka Bergmans, 1991 Nucula kerguelensis Thiele, 1912 Nucula libera Bergmans, 1991 Nucula malabarica Hanley, 1860 Nucula mariae Nolf, 2005 Nucula marmorea Hinds, 1843 Nucula marshalli Schenck, 1939 Nucula mayi (Iredale, 1930) Nucula mesembrina (Hedley, 1916) Nucula mitralis Hinds, 1843 Nucula multidentata Prashad, 1933 Nucula nicklesi Cosel, 1995 Nucula nitidosa Winckworth, 1930 (unaccepted name: Nucula turgida Leckenby & Marshall, 1875) Nucula nitidula A. Adams, 1856 Nucula nitidulaformis Powell, 1971 Nucula notobenthalis Thiele, 1912 Nucula nucleus (Linnaeus, 1758) Nucula oppressa Bergmans, 1991 Nucula papillifera Thiele & Jaeckel, 1931 Nucula paulula A. Adams, 1856 Nucula percrassa (Conrad, 1858 ) Nucula pisum G. B. Sowerby I, 1833 Nucula planiculmen Kilburn, 1999 Nucula praetenta Iredale, 1924 Nucula profundorum E. A. Smith, 1885 Nucula proxima Say, 1822 - Atlantic nutclam Nucula pseudoexigua Villarroel & Stuardo, 1998 Nucula pusilla Angas, 1877 Nucula recens Dell, 1956 Nucula revei Bergmans, 1978 Nucula rhytidopleura Kilburn, 1999 Nucula rossiana Finlay, 1930 Nucula rugulosa G. B. Sowerby I, 1833 Nucula saltator (Iredale, 1939) Nucula schencki Hertlein & Strong, 1940 Nucula sculpturata G. B. Sowerby III, 1904 Nucula semen Thiele & Jaeckel, 1931 Nucula semiornata d'Orbigny, 1842 Nucula sericea Thiele & Jaeckel, 1931 Nucula striolata A. Adams, 1856 Nucula suahelica (Thiele & Jaeckel, 1931) Nucula subluxa Kilburn, 1999 Nucula subovata Verrill & Bush, 1898 Nucula sulcata Bronn, 1831 Nucula sultana Thiele & Jaeckel, 1931 Nucula surinamensis Van Regteren Altena, 1968 Nucula tamatavica Odhner, 1943 Nucula tenuis (Montagu, 1808) Nucula tersior Marwick, 1929 † Nucula thielei Schenck, 1939 Nucula tokyoensis Yokoyama, 1920 Nucula torresi E. A. Smith, 1885 Nucula trigonica Lan & Lee, 2001 Nucula tumidula (Malm, 1860) Nucula venezuelana Weisbord, 1964 Nucula vincentiana (Cotton & Godfrey, 1938) Nucula zophos A. H. Clark, 1960
Extinct species Extinct species within the genus Nucula include:Fossilworks
N. alcocki † Noetling 1895 N. andersoni † Clark & Durham 1946 N. assiniboiensis † Russell & Landes 1937 N. athabaskensis † McLearn 1931 N. brewsterensis † Hassan 1953 N. cancellata † Meek & Hayden 1857 N. cancellata † Vredenburg 1928 N. catalina † Olsson 1930 N. chrysocoma † Dall 1908 N. cilleborgensis † Ravn 1907 N. concinna † Sowerby 1836 N. cossmanni † Vincent 1892 N. costaeimbricatus † Newton 1922 N. crepida † Marwick 1931 N. cunifrons † Conrad 1860 N. domandaensis † Eames 1951 N. gabbiana † Dickerson 1916 N. greppina † Deshayes 1858 N. major † Richards 1944 N. mancorensis † Olsson 1931 N. martini † Finlay 1927 N. micheleae † Marincovich jr. 1993 N. morundiana † Tate 1886 N. narica † Vredenburg 1928 N. nejdensis † Abbass 1972 N. njalindugensis † Martin 1919 N. observatoria † Ihering 1907 N. orbicella † Olsson 1922 N. paboensis † Olsson 1931 N. paytensis † Adams 1856 N. piacentina † Lamarck N. pilkeyi † Ward & Blackwelder 1987 N. planimarginata † Meek & Hayden 1857 N. praemissa † Semper 1861 N. prunicola † Dall 1898 N. rembangensis † Martin 1919 N. reticularis † Ortmann 1900 N. sedanensis † Haanstra & Spiker 1932 N. semistriata † Tate 1886 N. shaleri † Dall 1894 N. sinaria † Dall 1898 N. stantoni † Stephenson 1923 N. studeri † d'Archiac 1850 N. subrotundata † Morningstar 1922 N. subtransversa † Nyst 1844 N. suprastriata † Arnold 1903 N. tallahalaensis † Dockery 1982 N. taphria † Dall 1898 N. tatriana † King 1850 N. tersior † Marwick 1929 N. tumida † Tenison Woods 1877 N. turgens † Wood 1879 N. venezuelana † Weisbord 1964 N. ventricosa † Hall 1868 N. vestigia † Marwick 1929 N. vicksburgensis † Conrad 1848 N. waikuraensis † Marwick 1931 N. washingtonensis † Weaver 1916
References
Powell A. W. B., New Zealand Mollusca, William Collins Publishers Ltd, Auckland, New Zealand 1979