Cardiida
| Cardiida | ||||||||||||
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Lagoon cockle ( Cerastoderma glaucum ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Cardiida | ||||||||||||
| Férussac , 1822 |
The Cardiida are an order of clams .
features
The same-folding, m housings are very small to very large. In outline, they are predominantly rounded-triangular, transverse-ovoid or transverse-elliptical, rarely high-ovoid or high-elliptical, also approximately transverse rectangular shapes occur. The vertebrae are small, flat and slightly protruding (Tellinoidea) or large and distended (Cardioidea). The lock has two main teeth in each valve and some lateral teeth, but these can also be reduced or completely absent. The external ligament lies on nymphs behind the vertebrae. In some groups there is also an inner, triangular resilium. The surface line is not indented or indented very deeply. The two sphincters are usually about the same size, but can often have very different shapes. In a small group, the anterior sphincter is reduced. The siphons of different lengths are separated.
The aragonitic shell is thin and translucent to very thick. The ornamentation usually consists of radial ribs of different strength, thickness and number, which are often covered with knots, scales or thorns (cardioidea) or the surface is smooth or provided only with weak growth strips parallel to the edge. On the other hand, there are color patterns that are parallel to the edge or that are laid out radially and also spotty. The periostracum is usually thin.
Geographical distribution, habitat and way of life
The order is spread all over the world. Most species live in shallow marine areas. Most types of Cardioidea live buried shallowly in sandy, fine sandy or muddy soils, and are suspension filter feeders. The few species of the genera Corculum and Tridacna have endosymbiotic dinoflagellates . The majority of the Tellinoidea species are actively digging suspension filters in soft soils, living more or less deep in the sediment, or they pipette off the sediment surface with the help of the inflow siphon.
Taxonomy
The taxon was introduced in 1822 by André Étienne d'Audebert de Férussac as Cardiacés. The MolluscaBase assigns two superfamilies to the order Cardiida:
- Cardiida Férussac, 1822
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Cardioidea Lamarck, 1809
- Cockles (Cardiidae Lamarck, 1809)
- Pterocardiidae Scarlato & Starobogatov, 1979 †
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Tellinoidea Blainville, 1814
- Luggage clams (Donacidae Fleming, 1828)
- Icanotiidae Casey, 1961 †
- Sand mussels (Psammobiidae Fleming, 1828)
- Quenstedtiidae Cox, 1929 †
- Pepper shells (Semelidae Stoliczka, 1870 (1825))
- Solecurtidae d'Orbigny, 1846
- Sowerbyidae Cox, 1929 †
- Tancrediidae Meek, 1864 †
- Tell clams (Tellinidae Blainville, 1814)
- Unicardiopsidae Chavan, 1969 †
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Cardioidea Lamarck, 1809
literature
- Michael Amler, Rudolf Fischer & Nicole Rogalla: Mussels . 214 pp., Haeckel-Bücherei, Volume 5. Enke Verlag, Stuttgart 2000 ISBN 3-13-118391-8 (pp. 105/6, 107, 109)
Individual evidence
- ↑ André Étienne d'Audebert de Férussac: Tableaux systématiques des animaux mollusques classés en familles naturelles, dans lesquels on a établi la concordance de tous les systèmes; suivis d'un prodrome general pour tous les mollusques terrestres ou fluviatiles, vivants ou fossils. Paris, A. Bertrand, 1821–1822 Online at www.biodiversitylibrary.org (S. XVII)
- ↑ MolluscaBase: Cardiida