Mactra lilacea
| Mactra lilacea | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Mactra lilacea | ||||||||||||
| Lamarck , 1818 |
Mactra lilacea is a shell - type from the family of white clams (Mactridae). It only migrated from the Red Sea through the Suez Canal into the southeastern Mediterranean at the end of the 20th century; is therefore a Lessepsian immigrant in the Mediterranean.
features
The equally-flared, somewhat expanded housing is up to 6.5 cm long: in the Mediterranean, the species remains smaller (here according to Zenetos et al .: 30 to 40 mm long and 23 to 29 mm high). The case gapes a little in the back, even when closed. The vertebrae, which are rolled up to the front, are roughly centered in relation to the length of the case or only slightly shifted forward, i.e. H. the housing is almost equilateral. It is transversely ovoid in outline. The anterior dorsal margin is slightly concave and sloping steeply, the rear dorsal margin is slightly convex to straight and sloping a little flatter. The ventral margin is well arched. The rear end is slightly more rounded than the front end. The ligament is located inside on a spoon-shaped extension of the shell ("chondrophor") under the vertebra. The left valve lock consists of two main teeth that form an inverted V-shaped structure and an anterior and posterior posterior tooth. The right valve has two main teeth that are not connected to each other. and two anterior and posterior posterior teeth. The surface line is only slightly indented.
The aragonitic shell is comparatively thin and brittle. The ornamentation consists of slightly uneven, fine ribs parallel to the edge at somewhat regular intervals. The ornamentation is more pronounced in the front housing part than in the rear housing part. The inner edge of the case is smooth. The color varies from white to white with a distinct purple tint. The vertebrae are all purple in color. The outside is either uniformly colored or has lighter, radial rays.
Similar Art
Mactra lilacea is very similar to Mactra olorina, which also immigrated from the Red Sea to the Mediterranean . However, this species is ribbed more regularly and evenly. In addition, the latter type is usually yellowish to beige in color, rarely with a purple tinge. The eddies are always white.
Geographical distribution, habitat and way of life
The distribution area extends over much of the tropical coastal waters of the western Pacific and Indian Oceans including the Red Sea , the Gulf of Aqaba and the Gulf of Suez . It was first found in 1972 in the Bay of Bardawil (Nile Delta, Egypt ). In 2001 the species was found for the first time and also alive on the coast of Israel. In a work from 2014, it was now also detected from the Lebanese coast.
The species is a suspension filter and occurs shallowly buried in sandy soils in shallow water. On the Israeli coast it lives in 6 to 9 meters water depth.
Taxonomy
The taxon was founded in 1818 by Jean-Baptiste de Lamarck . The MolluscaBase regards it as a valid taxon.
supporting documents
literature
- Peter Graham Oliver, Kevin Thomas (pictures): Bivalved seashells of the Red Sea. 330 pp., Wiesbaden, Hemmen et al. a., 1992 (p. 131)
- Argyro Zenetos, Serge Gofas, Giovanni Russo, José Templado: CIESM Atlas of Exotic Species in the Mediterranean. Vol.3 Mollusca. CIESM (Frédéric Briand, ed.), Monaco, 2003 (p. 280/81)
Individual evidence
- ^ G. Bitar: Les mollusques exotiques de la côte Libanaise. Bulletin de la Société Zoologique de France, 139 (1/4): 37-45, 2014 abstract
- ↑ Jean-Baptiste de Lamarck: Histoire naturelle des animaux sans vertèbres. Tome cinquième. 612 p., Paris, Deterville / Verdière, 1818 Online at www.biodiversitylibrary.org (p. 479 with wrong type locality)
- ↑ MolluscaBase: Mactra lilacea Lamarck, 1818