Northern Astarte
| Northern Astarte | ||||||||||||
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Northern Astarte ( Astarte borealis ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Astarte borealis | ||||||||||||
| ( Schumacher , 1817) |
The Northern Astarte ( Astarte borealis ) is a shell -Art from the family of Astarte (Astartidae).
features
The equally-flattened, somewhat flattened housings are rounded to broadly elliptical in outline with a maximum diameter of 4.5 centimeters. The dorsal angle is only a little more than 90 °. The anterior dorsal margin is slightly concave, the rear dorsal margin is slightly convex. The front edge is well rounded, the rear edge somewhat trimmed. The ventral margin is well rounded. The vertebra is slightly in front of the center and is flat. It is often corroded. The ligament is external and raised. Lunula and area are well developed and comparatively narrow. The inner edge of the case is smooth.
The lock of the right valve has two cardinal teeth, the front tooth of which is wide and the rear tooth is narrow. Above the posterior sphincter there is a lateral and distinct pit and flange, and above the anterior sphincter there is a lateral back. The left valve has three cardinal teeth, the back of which is small and indistinct. There is a lateral flange over the posterior sphincter and a lateral pit over the anterior sphincter.
The upper side is provided with coarse concentric growth lines, especially for the vertebrae to be able to strengthen the growth strips like ribs. The thick periostracum is light brown in juvenile specimens, dark brown to almost black in adult specimens. The shell itself is whitish and hard-shelled.
There are two egg-shaped and large sphincters of approximately the same size. The surface line is not indented.
Geographical distribution and habitat
The distribution area of the species extends from the Arctic to the North Sea and western Baltic Sea (Mecklenburg coast), in the western North Atlantic to Nova Scotia and Massachusetts. It occurs from shallow water (around 7 m in the Baltic Sea) to a depth of 3,000 meters in the North Atlantic. The occurrence in the Baltic Sea is the southernmost record of the species in the Atlantic. In the northern Pacific, the distribution area extends to northern Japan.
Astarte borealis lives buried in mud and fine sand soils just below the sediment surface, as their siphons are quite short. It does not have a pelagic larval stage. The water temperatures must not exceed 16 °.
Taxonomy
The taxon was first scientifically described in 1817 by Christian Friedrich Schumacher as Tridonta borealis . It is the type of the genus Tridonta Schumacher, 1817, a younger synonym of Astarte J. de C. Sowerby, 1816. The MolluscaBase summarizes Astarte bornholmi Høpner Petersen, 2001 and Astarte silki Høpner Petersen, 2001 as synonyms of the Northern Astarte ( Astarte borealis ) on.
supporting documents
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. 245)
- Fritz Nordsieck : The European sea shells (Bivalvia). From the Arctic Ocean to Cape Verde, the Mediterranean Sea and the Black Sea. 256 p., Gustav Fischer Verlag, Stuttgart 1969 (p. 70 as Tridonta borealis )
- Guido Poppe, Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda) . 221 pp., Verlag Christa Hemmen, Wiesbaden 1993 (2000 unc. Reprint), ISBN 3925919104 (p. 90)
- Rainer Willmann: Mussels and snails of the North and Baltic Seas. 310 p., Neumann-Neudamm, Melsungen 1989, ISBN 3-7888-0555-2 (p. 110)
On-line
Individual evidence
- ^ Christian Friedrich Schumacher: Essai d'un nouveau système des habitations des vers testacés. 287 pp., 22 plates, Copenhagen, Schultz, 1817 Online at www.biodiversitylibrary.org (p. 147)
- ↑ MolluscaBase: Astarte borealis (Schumacher, 1817)
