Noah's ark shell

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Noah's ark shell
Noah's ark shell (Arca noae)

Noah's ark shell ( Arca noae )

Systematics
Order : Arcida
Superfamily : Arcoidea
Family : Ark clams (Arcidae)
Subfamily : Arcinae
Genre : Arca
Type : Noah's ark shell
Scientific name
Arca noae
Linnaeus , 1758

The Noah's ark shell ( Arca noae ) is a type of shell from the order of the Arcida . It is a very distinctive species found in the North Sea, the Atlantic and the Mediterranean.

features

The noah's ark shell, which has the same flaps, is up to 8 cm long and 4 cm high. It is rounded rectangular with an almost straight upper edge. The vertebrae are located in the front third of the case and are turned forward; they are relatively far apart. The right and left valves are almost the same, but the valves are inaequilateral, that is, they are greatly extended backwards in relation to the vertebra. From the vertebrae radiate strong ribs that are cut and interrupted by growth lines. The surface is covered by a thick, leafy (or hairy) periostracum . The basic color is mostly brown, light brown to cream colored, often with darker, mostly brown concentric bands. Overall, the Noah's Ark shell is very variable in the shape and color of the case. The lock is taxodont (same-toothed), which means it consists of many, small, approximately equal-sized teeth. The ligament is long and consists of an anterior area with a lamellar structure and a posterior area with a fibrous structure. The sphincters are about the same size, the surface line is indented. The Noah's Ark shell has simple eyes on the edge of the mantle that react to sudden shadowing and thus to movement.

Geographical distribution, habitat and way of life

The distribution area of ​​the Noah's Ark mussel is the eastern Atlantic from the Algarve (Portugal) to West Africa ( Senegal ) and the Mediterranean. It is also found in the coastal waters of the Canary Islands and the Cape Verde Islands .

The animals live with byssus attached to hard substrates or on horn corals in areas with little light (such as crevices in the shallower water). However, you can loosen the byssus, move around slightly, and reattach yourself. In the water column they occur from just below the low water line to about 119 m water depth. A depth distribution of up to 60 m has been observed on the Croatian Adriatic coast. The animals live there individually or in small colonies, often together with the bearded mussel ( Modiolus barbatus (Linné, 1758)), which is also attached by a byssus . The highest population density observed there was 12 individuals per m 2 . The animals can live up to 15 years and only reach an (economically interesting) size of 5 cm at the age of 3 to 7 years. The animals are separate sexes, but interestingly, hermaphrodites were also observed in a small percentage (approx. 2%) . Also protandry seems to occur.

Economical meaning

In the Mediterranean Sea, Noah's Ark clam is collected and eaten locally. The economic importance is low, however, since the population densities are relatively low.

Taxonomy

The taxon was established by Carl von Linné as early as 1758 . It is the type of the genus Arca Linné, 1758. According to the variability of the shape and color of the case, there are a large number of names for Noah's Ark. Altogether there are more than 20  synonyms for this species. The misspelling Arca noe is also common in older literature .

supporting documents

literature

  • Rudolf Kilias: Lexicon marine mussels and snails. 2nd edition, Verlag Eugen Ulmer, Stuttgart 1997 ISBN 3-8001-7332-8 , p. 25.
  • Fritz Nordsieck : The European sea shells (Bivalvia). From the Arctic Ocean to Cape Verde, the Mediterranean Sea and the Black Sea. Gustav Fischer Verlag, Stuttgart 1969, p. 19.
  • Guido Poppe, Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda). Verlag Christa Hemmen, Wiesbaden 1993 (2000 unc. Reprint), ISBN 3-925919-10-4 , p. 42.
  • Rosina Fechter, Gerhard Falkner: Mollusks. Mosaik-Verlag, Munich 1990 (= Steinbach's Nature Guide 10), ISBN 3-570-03414-3 .
  • Brian Morton, Melita Peharda: The biology and functional morphology of Arca noae (Bivalvia: Arcidae) from the Adriatic Sea, Croatia, with a discussion on the evolution of the bivalve mantle margin. In: Acta Zoologica . 89: pp. 19-28, Stockholm 2008, doi: 10.1111 / j.1463-6395.2007.00288.x (English).

Individual evidence

  1. ^ P. Graham Oliver, Rudo von Cosel: Taxonomy of Tropical West African Bivalves. IV. Arcidae. Bulletin du Muséum national d'Histoire naturelle du Paris, 4th series, secion, 14A (2): 293–381, Paris 1992 PDF
  2. ^ 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, Holmiae / Stockholm, Salvius, 1758. Online at Göttinger Digitization Center, p. 693.
  3. ↑ World Register of Marine Species: Arca noae Linnaeus, 1758

Web links

Commons : Noah's Ark shell ( Arca noae )  - Collection of images, videos and audio files