Caecum (gastropod)


Caecum is a genus of minute sea snails, marine gastropod micromolluscs or micromollusks in the family Caecidae or blind shells.

Distribution

This genus occurs worldwide in warm and temperate seas. Many species live in sponges, in sandy spots on reefs, or in grassy beds in shallow waters in bays and lagoons. Some species are very common and can be extremely numerous where they do occur, such as the "beautiful caecum", but even they can be easily overlooked as they are so tiny. Many species are considered to be uncommon, but this assessment may be a result of lack of proper sampling.

Shell description

The shells in this genus, like the others in the family, are very small with a length between 2 mm and 6 mm. Their colour is white to yellowish white and some are almost translucent. They are unusual in that the teleoconch of the adult shell is a curving tube for most of its length. In the first stage of the shell it is spiral-shaped but soon becomes cylindrical.
The shell is sealed with a permanent calcareous plug at one end and with a circular, multispiral, horny operculum at the other end, the shell aperture. The sculpture is smooth or consists of a close-set, large number of annular ridges.

Feeding habits

These snails feed on one-celled organisms on sand grains or pebbles.

Species

Species in the genus Caecum include:
  • † Caecum aartseni Van Dingenen, Ceulemans & Landau, 2016 Caecum achirona Caecum adamsi Raines, 2020Caecum amputatum Ch. Hedley, 1894 Caecum amydroglyptum Rehder, 1980 Caecum angustum de Folin, 1879Caecum annulatum Emmons, 1858Caecum antillarum Carpenter, 1858 - Antillean caecumCaecum arabicum Issel, 1869Caecum armoricum de Folin, 1869 - De Folin's lagoon snail. This species is fully protected in the United Kingdom under the Wildlife and Countryside Act 1981 since 1992.Caecum atlantidis R. B. Watson, 1897 Caecum attenuatum de Folin, 1879 Caecum auriculatum de Folin, 1868 Caecum austrafricanum Vannozzi, Pizzini & Raines, 2015Caecum australe Pizzini & Raines, 2011Caecum bathus Pizzini, Raines & Vannozzi, 2013
  • † Caecum benhami Goedert & Raines, 2016
  • † Caecum bensoni Goedert & Raines, 2016 Caecum beaufortensis Ward and Blackwelder 1987 Caecum bimamillatum de Folin, 1867Caecum bimarginatum Carpenter, 1859Caecum biomaglo Vannozzi, 2023Caecum bipartitum de Folin, 1870 Caecum borneoense de Folin, 1867Caecum bounty Pizzini & Raines, 2011Caecum brasilicum de Folin, 1874 Caecum brennani Raines & Pizzini, 2009Caecum breve de Folin, 1867Caecum bucerium Golikov, 1967Caecum californicum Dall, 1885 - California caecum Caecum calvertense Martin, 1904 Caecum campanulatum Raines & Pizzini, 2005Caecum campe Pilsbry and Olsson, 1941 Caecum carolinianum Dall, 1892 - Carolina caecum
  • † Caecum carpenteri Deshayes, 1861 Caecum caverna Moolenbeek, Faber & Iliffe, 1989 Caecum chilense Stuardo, 1962 Caecum chinense de Folin, 1879 Caecum chipolanum Gardner, 1947 Caecum cinctum Olsson & Harbison, 1953Caecum circumvolutum de Folin, 1867Caecum clarkii P. P. Carpenter, 1858 Caecum clarum Lamy, 1910 Caecum clathratum P. P. Carpenter, 1857 Caecum clava de Folin, 1867 - club caecum Caecum cocoense Sibaja-Cordero, García-Méndez & Troncoso, 2013Caecum codoceoae Gálvez & Huidobro, 2017Caecum condylum Moore, 1969 - bone caecumCaecum continens Van der Linden & Moolenbeek, 2000 Caecum cooki Pizzini & Raines, 2011Caecum cooperi S. I. Smith, 1860 - Cooper's Atlantic caecumCaecum corrugatulum Carpenter, 1857Caecum crassum de Folin, 1870Caecum crebricinctum Carpenter, 1864 - many-named caecum Caecum crispum A. E. Verrill & Bush, 1900 Caecum crystallinum de Folin, 1880Caecum cubitatum - smooth caecum Caecum cuspidatum Chaster, 1896 Caecum cycloferum de Folin, 1867 - fatlip caecum Caecum dakuwaqa Pizzini, Raines & Vannozzi, 2013 Caecum dalli Bartsch, 1920Caecum danielei Pizzini & Raines, 2011Caecum debile A. E. Verrill & Bush, 1900Caecum delicatulum A. E. Verrill & Bush, 1900Caecum derjugini Golikov, 1967Caecum dextroversum P. P. Carpenter, 1858 Caecum digitulum Hedley, 1904 Caecum diminutum C. B. Adams, 1852 Caecum directum Vannozzi, 2019Caecum donmoorei Mitchell-Tapping, 1979 Caecum draperi Raines, 2020Caecum dux de Folin, 1871Caecum eburneum C. B. Adams, 1852 Caecum egenum Vannozzi, 2017Caecum elegantissimum Carpenter, 1859Caecum eliezeri Absalao, 1997 Caecum elongatum P. P. Carpenter, 1857
  • Caecum engli Nofroni, Pizzini, Oliverio, 1997 Caecum eunoi Nofroni, Pizzini, Oliverio, 1997 Caecum exile de Folin, 1875 Caecum farcimen P. P. Carpenter, 1857 Caecum fijiense Pizzini, Raines & Vannozzi, 2013 Caecum firmatum C. B. Adams, 1852 Caecum floridanum Stimpson, 1851 - Florida caecumCaecum folini Kisch, 1959 Caecum frugi Vannozzi, 2019Caecum galapagoense Raines, 2020Caecum geigeri Pizzini & Raines, 2011Caecum glabellum A. Adams, 1868Caecum glabriforme Carpenter, 1857Caecum glabrum Caecum gofasi Pizzini & Nofroni, 2001Caecum granulatum Vannozzi, 2019Caecum greensboroense Martin, 1904 Caecum gulosum Hedley, 1899Caecum gurgulio Carpenter, 1858 - windpipe caecum Caecum hemphilli Bartsch, 1920 Caecum heptagonum Caecum heterochromum Raines & Pizzini, 2005Caecum hyalinum Vannozzi, 2022Caecum imbricatum Carpenter, 1858 - imbricate caecum Caecum incisum Vannozzi, Pizzini & Raines, 2015 Caecum imperforatum Kanamacher, 1798 Caecum inclinatum de Folin, 1869Caecum infimum de Folin, 1867Caecum inflatulum Vannozzi, 2017Caecum inflatum de Folin, 1867Caecum inhacaense Albano & Pizzini 2011Caecum insculptum Carpenter, 1857Caecum insularum Moore, 1969 Caecum intortum Vannozzi, Pizzini & Raines, 2015Caecum invisibile Egger & Jörger, 2020Caecum iricolor Vannozzi, 2023Caecum japonicum Caecum johnsoni Winkley, 1908Caecum jonatani Espinosa, Ortea & Fernandez-Garcés, 2007Caecum jonesae Swinnen & Simone, 2024Caecum jucundum de Folin, 1867Caecum knysnaense Vannozzi, Pizzini & Raines, 2015Caecum kontiki Pizzini & Raines, 2011Caecum laeve C.B. Adams, 1852Caecum lapita Pizzini, Raines & Vannozzi, 2013 Caecum laqueatum C. B. Adams, 1852
  • † Caecum larieyense Lozouet, Lesport & Renard, 2001 Caecum leilae Vannozzi, Pizzini & Raines, 2015Caecum lightfootanum Raines, 2020Caecum limnetes Long, 1972Caecum limpidum de Folin, 1874Caecum lindae Vannozzi, Pizzini & Raines, 2015Caecum lineicinctum de Folin, 1880Caecum liratocinctum Carpenter, 1857Caecum lohri Strong & Hertlein, 1939Caecum loyaltense Pizzini, Raines & Vannozzi, 2013 Caecum lozoueti Vannozzi & Renda, 2024Caecum lucidum de Folin, 1867Caecum macrum Van der Linden & Moolenbeek, 2000 Caecum maestratii Pizzini, Raines & Vannozzi, 2013 Caecum magellanicum di Geronimo, Privitera & Valdovinos, 1995Caecum malleatum de Folin, 1867
  • † Caecum mammillatum S. V. Wood, 1848 Caecum maori Pizzini & Raines, 2006Caecum maraisi Vannozzi, Pizzini & Raines, 2015Caecum marginatum de Folin, 1869Caecum marmoratum de Folin, 1869Caecum massambabense Absalao, 1994 Caecum mauritianum de Folin, 1867Caecum metamorphosicum S. Lima, Santos & Absalão, 2013Caecum microannulatum Vannozzi & Renda, 2024Caecum microstriatum Pizzini, Raines & Vannozzi, 2013 Caecum miliarium Vannozzi & Renda, 2024
  • † Caecum mineuri Lozouet, 1999 Caecum mirificum de Folin, 1867 Caecum modestum de Folin, 1867Caecum monstrosum C. B. Adams, 1852Caecum moorei Caecum morgan Vannozzi, Pizzini & Raines, 2015Caecum multicostatum de Folin, 1867Caecum musorstomi Pizzini, Raines & Vannozzi, 2013 Caecum nasutum Vannozzi, 2019
  • † Caecum nemoralis Lozouet, 2015 Caecum neocaledonicum de Folin, 1867Caecum neoguineanum Vannozzi, 2019Caecum nofronii Vannozzi, 2019Caecum oahuense H. A. Pilsbry, 1921 Caecum obtusum Carpenter, 1857Caecum occidentale - western caecum Caecum orcutti Caecum paradoxum de Folin, 1867 Caecum parvum C. B. Adams, 1852 Caecum pascuanum Raines & Pizzini, 2005
  • † Caecum pertenuis Laws, 1941 Caecum planum de Folin, 1874Caecum patuxentium Martin, 1904 Caecum plicatum Carpenter, 1858 - plicate caecum Caecum pollicare Carpenter, 1859Caecum praegrande Vannozzi, 2017Caecum profundicolum Bartsch, 1920 - deepwater caecum Caecum properegulare Mansfield, 1925 Caecum pulchellum Stimpson, 1851 - beautiful caecum Caecum pygmaeum C. B. Adams, 1852 Caecum quadratum P. P. Carpenter, 1857 Caecum rapanuiense Raines & Pizzini, 2005Caecum regulare Carpenter, 1858Caecum rehderi Raines & Pizzini, 2005Caecum restrictum Vannozzi & Renda, 2024Caecum reversum Carpenter, 1857Caecum richthofeni A. M. Strong & J. G. Hertlein, 1939 Caecum rijgersmai Jong & Coomans, 1988
  • † Caecum roederi Raines, C. L. Powell & LaFollette, 2023 Caecum rolani Pizzini & Nofroni, 2001Caecum rosanum Bartsch, 1920 Caecum rostratum de Folin, 1881Caecum ruggerii Pizzini, 1997 Caecum rugulosum Phil, 1836 Caecum ryssotitum de Folin, 1867 - minute caecumCaecum searleswoodii Carpenter, 1859Caecum semilaeve Carpenter, 1857Caecum senegambianum de Folin, 1870Caecum sepimentum de Folin, 1868 Caecum shaskyi Raines, 2020Caecum simplicissimum Thiele, 1925Caecum sinuatum de Folin, 1867Caecum skoglundae Pizzini, Raines & Nofroni, 2007Caecum smriglioi Pizzini, Nofroni & Bonfitto, 2008Caecum someri Caecum spiculum Raines, 2020Caecum striatum de Folin, 1875Caecum strictum de Folin, 1871Caecum strigosum de Folin, 1868Caecum subannulatum de Folin, 1870Caecum subaustrale Stuardo, 1970Caecum subconicum Carpenter, 1857Caecum subcylindratum Pizzini, Raines & Vannozzi, 2013 Caecum subflavum de Folin, 1879 Caecum subimpressum P. P. Carpenter, 1857 Caecum subobsoletum Carpenter, 1857Caecum subornatum de Folin, 1874 Caecum subspirale Carpenter, 1857Caecum subquadratum Carpenter, 1859Caecum subspirale Carpenter, 1857Caecum subvolutum de Folin, 1874Caecum succineum de Folin, 1879 Caecum swinneni Nofroni, Pizzini, Oliverio, 1997 Caecum taeniatum de Folin, 1869Caecum tahitianum Pizzini & Raines, 2011Caecum temporale Vannozzi & Renda, 2024Caecum tenue Verrill & Bush, 1900Caecum tenuicostatum de Folin, 1881Caecum tenuiliratum Carpenter, 1857
  • † Caecum tenuistriatum O. Boettger, 1869 Caecum teres Carpenter, 1857Caecum textile de Folin, 1867 - textile caecumCaecum tornatum A. E. Verrill & Bush, 1900 Caecum torquetum de Folin, 1867Caecum tortile Dall, 1892 - twisted caecumCaecum trachea G. Montagu, 1803 Caecum trindadense S. Lima, Santos & Absalão, 2013Caecum troglodyta Moolenbeek, Faber & Iliffe, 1989
  • † Caecum tumidum Carpenter, 1858 Caecum uncinatum de Folin, 1867 Caecum undatum P. P. Carpenter, 1857 Caecum vanuatuarum Pizzini, Raines & Vannozzi, 2013 Caecum varanoi Pizzini, Nofroni & Bonfitto, 2008Caecum variegatum de Folin, 1867Caecum venosum de Folin, 1867
  • † Caecum verai Moreno, Peñas & Rolán, 2003Caecum vertebrale Ch. Hedley, 1899 Caecum vicinum de Folin, 1870Caecum virginiae Pizzini, Raines & Vannozzi, 2013 Caecum vitreum P. P. Carpenter, 1858 Caecum wakense Raines & Vannozzi, 2024Caecum wami Raines & Pizzini, 2009Caecum wayae Pizzini & Nofroni, 2001Caecum zaagmani Jong and Coomans, 1988
; Subgenera brought into synonymy :Caecum Weisbord, 1962: synonym of Caecum Fleming, 1813Caecum Carpenter, 1859: synonym of Meioceras Carpenter, 1859
;Species brought into synonymy:Caecum abnormale Carpenter, 1857: synonym of Caecum subspirale Carpenter, 1857Caecum amaltheanum Hedley, 1899: synonym of Mauroceras legumen Caecum amamiense Habe, 1978: synonym of Mauroceras amamiense Caecum arcuatum de Folin, 1867 : synonym of Caecum sepimentum de Folin, 1868Caecum bahiahondaense A. M. Strong & J. G. Hertlein, 1939 : synonym of Caecum clathratum Carpenter, 1857Caecum bakeri : synonym of Caecum dextroversum Carpenter, 1857Caecum berthae Lange de Morretes, 1954: synonym of Caecum plicatum Carpenter, 1858Caecum biminicola Pilsbry, 1951: synonym of Caecum plicatum Carpenter, 1858Caecum buccina de Folin, 1870: synonym of Caecum circumvolutum de Folin, 1867Caecum bucheri Parenzan, 1979: synonym of Filogranula annulata Caecum butoti Jong & Coomans, 1988 : synonym of Caecum marmoratum de Folin, 1869Caecum capitanum de Folin, 1874: synonym of Caecum pulchellum Stimpson, 1851Caecum carmenense de Folin, 1870: synonym of Caecum circumvolutum de Folin, 1867Caecum carpenteri : synonym of Caecum adamsi Raines, 2020Caecum cayoense Rehder, 1943: synonym of Caecum floridanum Stimpson, 1851Caecum clenchi Olsson & McGinty, 1958: synonym of Caecum cycloferum de Folin, 1867Caecum compactum P. P. Carpenter, 1857 : synonym of Caecum quadratum Carpenter, 1857Caecum conjunctum de Folin, 1867: synonym of Caecum pulchellum Stimpson, 1851Caecum contractum de Folin, 1870: synonym of Caecum bipartitum de Folin, 1870Caecum corneum R. W. Dunker, 1875 : synonym of Caecum ryssotitum de Folin, 1867Caecum cornucopiae - horn-of-plenty caecum : synonym of Meioceras cornucopiae Carpenter, 1859Caecum coronatum de Folin, 1867: synonym of Caecum imbricatum Carpenter, 1858Caecum coronellum Dall, 1892: synonym of Caecum cycloferum de Folin, 1867Caecum costatum A. E. Verrill, 1872: synonym of Caecum cooperi S. I. Smith, 1860Caecum crassicostum Gabb, 1881: synonym of Caecum floridanum Stimpson, 1851Caecum curtatum de Folin, 1867: synonym of Caecum pulchellum Stimpson, 1851Caecum decussatum de Folin, 1869: synonym of Caecum plicatum Carpenter, 1858Caecum dux de Folin, 1871: synonym of Caecum floridanum Stimpson, 1851Caecum eburneum de Folin, 1886: synonym of Caecum folini Kisch, 1959 Caecum elagans Deregaslavtseva, 1891: synonym of Caecum trachea Caecum elegans Perejoslavitseva, 1831 : synonym of Caecum trachea Caecum fasciatum de Folin, 1876: synonym of Caecum trachea Caecum formulosum de Folin, 1869: synonym of Caecum imbricatum Carpenter, 1858Caecum fulvum Kisch, 1959: synonym of Caecum neocaledonicum de Folin, 1867Caecum heladum Olsson and Harbison, 1953 - fine-line caecum : synonym of Caecum multicostatum de Folin, 1867Caecum heterapex T. Habe, 1963 : synonym of Caecum clarum Lamy, 1910 Caecum hinoidei T. Habe, 1978 : synonym of Caecum neocaledonicum de Folin, 1867Caecum insigne de Folin, 1867: synonym of Caecum imbricatum Carpenter, 1858Caecum instructum de Folin, 1870: synonym of Caecum bipartitum de Folin, 1870Caecum irregulare de Folin, 1867: synonym of Caecum floridanum Stimpson, 1851Caecum legumen Hedley, 1904: synonym of Meioceras legumen Caecum leptoglyphos de Folin, 1881: synonym of Caecum textile de Folin, 1867Caecum lermondi Dall, 1924: synonym of Meioceras nitidum Caecum lightfootae Pizzini, Nofroni, Oliverio, 1994 : synonym of Caecum atlantidis Watson, 1897Caecum lilianum Ch. Hedley, 1903 : synonym of Caecum sepimentum de Folin, 1867Caecum maculatum T. Habe, 1963 : synonym of Caecum sepimentum de Folin, 1867Caecum malleatum var. sublaevis de Folin, 1868: synonym of Caecum modestum de Folin, 1868 Caecum microcyclus de Folin, 1879 : synonym of Caecum attenuatum de Folin, 1880 Caecum nitidum Stimpson, 1851 - little horn caecum: synonym of Meioceras nitidum Caecum obesum A. E. Verrill & Bush, 1900 : synonym of Caecum plicatum Carpenter, 1858Caecum orientale de Folin, 1868 : synonym of Caecum clarkii Carpenter, 1859Caecum phronimum de Folin, 1867 : synonym of Caecum floridanum Stimpson, 1851Caecum puntagordanum Weisbord, 1962: synonym of Caecum floridanum Stimpson, 1851Caecum putnamense Mansfield, 1924 : synonym of Caecum johnsoni Winkley, 1908Caecum rotundum de Folin, 1868 : synonym of Meioceras nitidum Caecum saavedrae Beltran, 1965 : synonym of Caecum auriculatum de Folin, 1868Caecum sardinianum de Folin, 1869 : synonym of Caecum clarkii Carpenter, 1859Caecum sculptum de Folin, 1881: synonym of Caecum imbricatum Carpenter, 1858Caecum semitracheum S. Brusina, 1865 : synonym of Caecum clarkii Carpenter, 1859Caecum smithi Cooper, 1872: synonym of Caecum cooperi S. Smith, 1860Caecum solitarium Oliver, 1915 : synonym of Caecum maori Pizzini & Raines, 2006Caecum syriacum de Folin, 1869: synonym of Caecum auriculatum de Folin, 1868Caecum tenue A. E. Verrill & Bush, 1900: synonym of Caecum armoricum de Folin, 1869Caecum termes Heilprin, 1889: synonym of Caecum plicatum Carpenter, 1858Caecum tomaculum : synonym of Caecum ryssotitum de Folin, 1867Caecum triornatum de Folin, 1870: synonym of Caecum bipartitum de Folin, 1870Caecum uvea Pizzini, Raines & Vannozzi, 2013: synonym of Caecum folini Kisch, 1959 Caecum veracruzanum Collins, 1937 : synonym of Caecum circumvolutum de Folin, 1867Caecum vestitum de Folin, 1868 - Vera Cruz caecum: synonym of Caecum circumvolutum de Folin, 1867
; Nomina dubia :Caecum abreviatum de Folin, 1870 Caecum achates Sykes, 1925: taxon inquirendumCaecum bicinctum de Folin, 1870 Caecum gracile Carpenter, 1858 Caecum hemisphericum de Folin, 1867
  • ''Caecum imperforatum''