Lingula is a genus of brachiopods within the class Lingulata. Lingula is known to have existed since the early Ordovician Period.^[1] Lingula is considered an example of a living fossil. Like all brachiopods, it is a filter feeder. Brachiopods are superficially similar to a bivalve, both having two shells. Brachiopods are easily distinguished from molluscs however, in having (different) dorsal and ventral shells (bivalves have mirrored right and left shells). Lingula and almost all other brachiopods also have a stalk (or pedicle) that extends through a hole near the tip of one of its shells (bivalves may be attached to a substrate with byssus filaments, that extend from between the shells).

Species

The following species are recognised:^[2]

• Lingula adamsi Dall, 1873
• Lingula anatina Lamarck, 1801
• Lingula dregeri Andreae, 1893
• Lingula eocenica Moroz & Ermokhyna, 1990
• Lingula parva Smith, 1871
• Lingula reevii Davidson, 1880
• Lingula rostrum (Shaw, 1798)
• Lingula tenuis Sowerby
• Lingula translucida Dall, 1921
• Lingula tumidula Reeve, 1841
• Lingula waikatoensis Pen, 1930

Gallery

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  The sole evidence of the existence of Lingula anatina is a small three-lobed slit on the surface

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  Lingula anatina in tubes in the sand; the upper figure shows a three-lobed iopening on the surface of the sand; the dotted line in the lower figure indicates position in retraction

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  Lingula anatina: animal removed from the shell, mantle reflected, coiled arms separated slightly; a) mouth (marginal setae omitted); ventral aspect, three-quarter face

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  Lingula anatina: interior of the valve showing muscle scars; V. peduncle valve D. brachial valve

References