Donax trunculus

Donax trunculus
Donax trunculus (from Louis Figuier, 1872: p. 320, Fig. 127)
Systematics
Superordinate : Imparidentia Order : Cardiida Superfamily : Tellinoidea Family : Luggage clams (Donacidae) Genre : Donax Type : Donax trunculus
Scientific name
Donax trunculus
Linnaeus , 1758

Donax trunculus is a type of mussel from the trunk clam family(Donacidae).

features

The compressed housings are up to 40 millimeters long. They are rounded triangular in outline, but significantly longer than high (length to width ratio about 2 to 2.3). The shape is somewhat variable, however. They are slightly unevenly folded, the vertebra of the left valve is a little higher. They are also strongly asymmetrical, with the vertebra sitting well behind the center line in relation to the length of the case. The anterior and posterior dorsal margins are approximately straight, but form an obtuse angle to one another. The rear end is truncated at an angle. This feature is only developed in adult housings, ie juvenile housings are still well rounded at the rear end. The front edge is narrow and regularly rounded. It merges into the broadly rounded ventral margin. The lock has two main teeth in each of the two flaps. The ligament is small. The animals have very strong and flexible feet. The siphons are very long, but clearly different, and both siphons are thin.

The ornamentation consists of fine radial grooves, otherwise the surface is almost smooth. The grooves are lost towards the front end. The shell is yellowish or tinted purple, inside it is reddish or purple in color with white areas, the edge of the housing is white. The periosteal space is a thin brown or olive colored coating. The inside edge of the housing is notched.

The populations of the North Atlantic and the Mediterranean differ somewhat in shape. The cases from the North Atlantic are larger and have a longer rear end. A third form lives in the Adriatic, which is characterized by a more curved ventral edge.

Geographical distribution and habitat

Donax trunculus is widespread from the Bay of Biscay to West Africa on the heights of Senegal. It is also found in the Mediterranean and Black Seas.

The species lives almost vertically buried in sandy soils from the low water line to about 70 meters water depth. The foot is very strong and flexible. The animals can catapult themselves into the air with a quick foot movement or over a distance of 25 to 30 cm.

The animals are of separate sex. They become sexually mature in the second year. The sex products are released into the open water from around May to July, where they are fertilized. The animals live to be four years old.

Economical meaning

At the beginning of the 20th century, the species was very common on the French Atlantic coast and was fished intensively. The mussel was considered poor people's food. The species is still found there, but has become rare. In the Mediterranean the species z. Some are still fished, also on the coast of southern Portugal.

Taxonomy

The taxon was proposed by Carl von Linné in 1758 under the binomial Donax trunculus , which is still valid today . It is the type species of the subgenus Serrula Mörch, 1853.

literature

• S. Peter Dance, Rudo von Cosel (arrangement of the German edition): The great book of sea shells. 304 p., Verlag Eugen Ulmer, Stuttgart, 1977 ISBN 3-8001-7000-0 (p. 260)
• Rudolf Kilias: Lexicon marine mussels and snails. 2nd edition, 340 p., Verlag Eugen Ulmer, Stuttgart 1997 ISBN 3-8001-7332-8 (p. 98)
• Markus Huber: Compendium of Bivalves. A full-color guide to 3,300 of the world's marine bivalves. A status on Bivalvia after 250 years of research. 901 pp., 1 CD-ROM, Hackenheim, ConchBooks, 2010
• Guido Poppe and Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda) . 221 pp., Verlag Christa Hemmen, Wiesbaden 1993 (2000 unc. Reprint), ISBN 3925919104 (p. 113)

Individual evidence

1. ^ ^{A b} Louis Figuier: The ocean world: being a description of the sea and some of its inhabitants. Translated from the French by Edward Perceval Wright, New York, D. Appleton, 1872 Online at www.biodiversitylibrary.org (p. 320)
2. ↑ M. Manca Zeichen, S. Agnesi, A. Mariani, A. Maccaroni, GD Ardizzone: Biology and Population Dynamics of Donax trunculus L. (Bivalvia: Donacidae) in the South Adriatic Coast (Italy). Estuarine, Coastal and Shelf Science, 54: 971-982, 2002 doi : 10.1006 / ecss.2001.0868
3. ^ Carl von Linné: Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. Pp. 1-824, Holmia / Stockholm, Salvius, 1758. Online at www.biodiversitylibrary.org (p. 682).
4. ↑ MolluscaBase: Donax trunculus Linnaeus, 1758