Anadara antiquata
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| ( Linnaeus , 1758) |
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Anadara antiquata is a shell - type from the family of ark shells (Arcidae) in the order of Arcida . It occurs in the Indo-Pacific.
features
The greatly expanded housing is up to 10 cm long. In the juvenile phase, the housings are slightly unevenly-hinged, in the adult stage they are then equally-hinged. They are very unequal, the vertebrae are in the front third of the case. The housings are elongated-egg-shaped in outline and, especially towards the rear, strongly elongated towards the lower ventral edge. The dorsal margin is long and straight, the anterior margin is slightly arched to straight. The anterior and dorsal margins form an almost rectangular to slightly obtuse angle. The dorsal and posterior edges, on the other hand, form a very flat angle. The rear edge is then almost straight at first and merges with the ventral edge in a tightly rounded manner. The vertebrae are twisted forward. The dorsal field is wide and the vertebrae are approximated. The ligament is narrow-rhombic.
The lock plate is comparatively wide. The upper edge is straight, the lower edge slightly concave. The lock is taxodont . The teeth are small in the middle and stand vertically. They initially get larger towards the edge, close to the edge like an angle (the angle points inwards), and at the very edge the teeth become smaller and more knotty again.
The whitish skin is very thick and firm; the housings are correspondingly heavy. The ornamentation consisted of approx. 35 radial ribs. The ribs are wider than the distances between the ribs. They are flattened at the top and are crossed by growth lines. Weak knots are formed at the crossing points. On the front edge, some ribs can also split into two towards the edge of the case. The inner edge is strongly notched, the notches correspond to the furrows between the ribs. The periostracum is brownish and consists of fine lamellae and bristles. However, it peels off easily and is mostly only preserved on the edge of the case and the spaces between the ribs.
Similar species
Anadara uropigimelana is very similar. The ribs are finely striped, not knotty, and the ribs at the front end do not divide.
Geographical distribution and way of life
The range of the species is the tropical Indo-Pacific . The species is also found in the Red Sea .
The animals live buried in muddy sandy bottoms in shallow water.
Way of life and reproduction
The animals feed on microorganisms as filter feeders. In studies in East Africa, no zooplankton but only phytoplankton were found in the stomachs of 80 specimens examined .
The species is separate from the sexes; in a larger study (> 1000 animals) no hermaphrodites were found. In the province of Batangas (Philippines), the animals reproduced all year round with two peaks in March / April and June to September. The sex products are released into the open water; there the fertilization takes place. In Java ( Indonesia ), however, a small percentage (<1%) of protandric hermaphrodites were found.
Taxonomy
The taxon was established as Arca antiquata by Carl von Linné as early as 1758 . The species is the type species of the genus Anadara Gray, 1847. MolluscaBase has the following synonyms: Arca scapha Gmelin, 1791, Anomalocardia transversalis H. Adams, 1872 and Anadara suggesta Iredale, 1939. This taxon is probably actually a species Complex that urgently needs to be revised.
commercial use
Anadara antiquata is collected commercially in East Asia. In the Philippines, the species is even cultivated in aqua farms.
literature
- Peter Graham Oliver, Kevin Thomas (pictures): Bivalved seashells of the Red Sea. 330 pp., Wiesbaden, Hemmen et al. a., 1992, p. 37.
Individual evidence
- ^ Lovell Augustus Reeve: Conchologia Iconica, or, Illustrations of the Shells of Molluscous Animals. Vol. 2, London, Reeve Brothers, 1843-1844 online at www.biodiversitylibrary.org (Plate 9, Fig. 60).
- ↑ PF Kasigwa & CG Mahika: The diet of the edible cockle Anadara antiquata L. (Bivalvia, Arcidae) in Dar es Salaam, Tanzania, during the northeast monsoons. Hydrobiologia, 209: 7-12, 1991 PDF
- ↑ Lourdes Toral-Barza, Edgardo D. Gomez: Reproductive Cycle of the Cockle Anadara antiquata L. in Calatagan, Batangas, Philippines. Journal of Coastal Research, 1 (3): 241–245, 1985 PDF (Jstor)
- ↑ Norma Afiati: Hermaphroditism in Anadara granosa (L.) and Anadara antiquata (L.) (Bivalvia: Arcidae) from Central Java. Journal of Coastal Development, 10 (3): 171–179, 2004. PDF (Research Gate)
- ^ Carl von Linné: Systema Naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Editio decima, reformata. (10th revised edition), Vol. 1: 824 p., Laurentius Salvius, Holmiae / Stockholm Biodiversity Heritage Library , p. 694.
- ↑ MolluscaBase: Anadara antiquata (Linnaeus, 1758)
- ^ Markus Huber: Compendium of bivalves. 901 S., Hackenheim, ConchBooks, 2010, ISBN 978-3-939767-28-2 , here p. 135 (left fig., 2nd row from above), p. 566.
- ^ MJ Broom: The Biology and Culture of Marine Bivalve Molluscs of the Genus Anadara. International Center for Living Aquatic Resources Management, Manila 1985 Preview at Google Books ISSN 0115-4389, p. 34.