Norwegian beaked mussel

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Norwegian beaked mussel
Norwegian beak mussel (Lyonsia norwegica) (from GB Sowerby II, 1859: Plate 2, Fig. 4 [1])

Norwegian beak mussel ( Lyonsia norwegica ) (from GB Sowerby II, 1859: Plate 2, Fig. 4)

Systematics
Subclass : Heterodonta
Order :
Superfamily : Pandoroidea
Family : Lyonsiidae
Genre : Lyonsia
Type : Norwegian beaked mussel
Scientific name
Lyonsia norwegica
( JF Gmelin , 1791)
Drawing of the living animal (after Maria Emma Gray, 1857, plate 327)

The Norwegian beaked mussel ( Lyonsia norwegica ) is a type of mussel from the Lyonsiidae family , which belongs to the large group of Anomalodesmata .

features

The slightly unevenly hinged housing is up to 44 mm long. The left flap is slightly more arched and larger than the right flap. It is slightly unequal, with the vertebrae in front of the midline. In outline, the housing is egg-shaped, the rear end is trimmed. There is a gap at the trimmed rear end as well as a little at the front end. The rear dorsal edge is straight, the rear end (or the transition to the rear edge) is angled. The anterior dorsal margin is also straight to only slightly arched and slopes slightly more steeply than the rear dorsal margin. The front end is well rounded. The front half of the ventral margin is straight, the second half slightly rounded. A lock plate and teeth are missing. The thin, light brown ligament lies internally below and behind the vertebra, and lies on an elongated, narrow back, which points at an angle of about 30 ° from the posterior dorsal margin to the posterior end. In the left flap a lithodesm points backwards. There is a very deep mantle bay that extends in front of the vertebrae. The two sphincters are small and about the same size.

The whitish, aragonitic skin is thin, fragile and translucent. It consists of an inner layer of layered mother-of-pearl , a middle layer of lenticular mother-of-pearl and an outer prismatic layer. The ornamentation consists of growth strips parallel to the edge and radial lines. The inner edge of the case is smooth. The periostracum is beige to pale brown. It is often covered with grains of sand and sea urchin spines, etc. The inner surface has a pearly sheen.

The soft body is whitish with a yellowish tint. The front part of the coat has a pony of a few protruding fringes. The siphons are short and have a fringe around the openings and some filaments around the base. The whitish foot is tongue-shaped and extendable. He owns a pit for the production of the byssus .

Geographical distribution and habitat

The distribution area extends from Iceland , the Faroe Islands and Norway to the Iberian Peninsula and Morocco . It is also found in the waters around Madeira and the Canary Islands , as well as in the Mediterranean . It lives in sandy and silty-sandy soils, half-buried in water depths of around 8 to 125 meters.

Taxonomy

The taxon was described by Johann Friedrich Gmelin in 1791 in the original combination Mya norwegica . In older publications it was often misspelled as Lyonsia norvergica . It is de facto type species of the genus Lyonsia Turton, 1822, since the formal type species, Mya striata Montagu, 1816 is a younger, subjective synonym of Mya norwegica Gmelin, 1791.

supporting documents

literature

  • Paul Chambers: Channel Island Marine Molluscs: An Illustrated Guide to the Seashells of Jersey, Guernsey, Alderney, Sark and Herm. 321 pp., Charonia Media, 2008, ISBN 978-0-9560655-0-6 , p. 283 Preview on Google Books
  • 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. 273)
  • 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. 156)
  • Guido Poppe. Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda) . 221 pp., Verlag Christa Hemmen, Wiesbaden 1993 (2000 unc. Reprint), ISBN 3925919104 (p. 136)

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 2, Fig. 4)
  2. ^ Maria Emma Gray: Figures of molluscous animals selected from various authors. Vol. 5. Longman, Brown, Green, Longmans and Roberts, London, 1857 Online at www.biodiversitylibrary.org (Plate 327)
  3. ^ Johann Friedrich Gmelin: Caroli a Linné, systema naturae. Tom. I. Pars VI. Pp. 3021-3910, Lipsiae / Leipzig. Beer, 1791 Online at www.biodiversitylibrary.org (p. 3222)
  4. ↑ MolluscaBase: Lyonsia norwegica (Gmelin, 1791)