Mactra glauca

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Mactra glauca
Mactra glauca (from GB Sowerby II, 1859: Plate 3, Fig. 24 [1])

Mactra glauca (from GB Sowerby II, 1859: Plate 3, Fig. 24)

Systematics
Superordinate : Imparidentia
Order :
Superfamily : Mactroidea
Family : Trough clams (Mactridae)
Genre : Mactra
Type : Mactra glauca
Scientific name
Mactra glauca
v. Born , 1778

Mactra glauca is a type of mussel from the family of trough mussels (Mactridae).

features

The evenly folded, slightly inflated housing reaches an adult size of 8 to 12 cm. It is unequal-sided, the small, pointed, forward-sloping vertebrae are in front of the midline (at about 45% of the length of the case from the front end). The outline of the case is slightly elliptical, the length / height ratio is about 1.3. The shorter, anterior dorsal margin sits slightly lower than the longer, posterior dorsal margin. The posterior and anterior dorsal margin are only slightly convex. Front and rear ends are well rounded. The closed housing gapes at the front and rear.

There is an external and an internal ligament ; they are separated from each other by a thin, cream-colored septum. The external ligament behind the vertebra is a small, dark brown band. The internal ligament sits in a large, spoon-shaped process ( chondrophor ). The top of the pit sits just below the vertebrae. The lunula is lanceolate, but not clearly separated. The area is convex and marked more clearly.

The left valve shows three cardinal teeth, two that form an inverted V-shaped structure directly in front of the ligamentous pit, and one very small, thin lateral tooth between the ligamentous pit and the two large cardinal teeth, which breaks off very easily. Close to the edge of the case and running parallel to it, there are small, lamellar posterior teeth in front and behind. There are two cardinal teeth in the right valve, and two weakly developed, lamellar, anterior and posterior lateral teeth. The lower lateral teeth are each slightly longer than the upper lateral teeth. The mantle is only slightly indented, the apex of the bay only extends a little beyond the posterior sphincter impression. There are two sphincters.

The shell is thin-walled but firm. The ornamentation consists of fine concentric lines and pits, which can also be coarser in the rear dorsal area. There are radial pale brown rays on the (cream) white shell. The periostracum is pale brown and becomes a little darker towards the front and rear ends. The inner edge of the case is smooth, the insides are glossy white with a pale brown tint.

Geographical distribution, habitat and way of life

The range of the species extends from the English Channel to the Mediterranean . It lives in mostly clean sandy soils from a little below the low water line to about 44 meters water depth. They live only a few inches deep buried in the sand.

Taxonomy

The taxon was established by Ignaz von Born in 1778 . The MolluscaBase accepts the taxon as a valid species.

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. 251)
  • Rudolf Kilias: Lexicon marine mussels and snails. 2nd edition, 340 p., Verlag Eugen Ulmer, Stuttgart 1997 ISBN 3-8001-7332-8 (p. 180 and fig. 320)
  • 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. 141)
  • Guido Poppe, Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda) . 221 pp., Verlag Christa Hemmen, Wiesbaden 1993 (2000 unc.Reprinted ), ISBN 3925919104 (p. 101)

On-line

Individual evidence

  1. ↑ George Brettingham Sowerby II : Illustrated index of British shells. containing figures of all the recent species, with names and other information. XV S., XXIV plate. London, Simpkin, Marshall & Co., 1859 Online at www.biodiversitylibrary.org (plate 3)
  2. ↑ Ignaz von Born: Index rerum naturalium Musei Caesarei Vindobonensis. Pars I.ma. Testacea. Directory of the natural rarities of the Imperial and Royal Naturalien Cabinet in Vienna. First part. Switchgear. 458 pp., Vindobona / Wien, Kraus, 1778 Online at www.biodiversitylibrary.org (p. 40).
  3. ↑ MolluscaBase: Mactra glauca (Born, 1778)

Web links

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