Arca noae
Noah's Ark shell ( Arca NoAE )
Noah's Ark shell ( Arca NoAE ) is a species of bivalve mollusc of the order Arcoida. She is a very characteristic way, which is found in the North Sea, the Atlantic and the Mediterranean.
Features
The case of Noah's Ark shell is up to about 8 cm long and up to about 4 inches high. It is rounded rectangular with an almost straight upper edge. The vertebrae are located in the anterior third of the housing and rotated forward; they are relatively far apart. Right and left flap are nearly equal, but the flaps inaequilateral, that is greatly extended to the rear in relation to the vertebrae. From the vortex go from radial- strong ribs, which are cut and interrupted by growth lines. The surface is covered by a thick, leafy (or hairy ) periostracum. The basic color is usually brown, light brown to cream, often with a darker, mostly brown concentric bands. Noah's Ark shell is generally very variable in housing form and coloring of the housing. The castle is taxodont ( gleichzähnig ), that is composed of many small, nearly equal teeth. Ligament is long and comprises a front region having a lamellar structure and a rear region having a fibrous structure. The sphincters are approximately equal, the surface line is logged. Noah's Ark - shell has the mantle margin simple eyes that respond to sudden shading and so on movement.
Occurrence, lifestyle and dissemination
The animals live with byssus attached to hard substrates or on horn corals in areas with little light (such as crevices in shallow water). However, you can solve the fine linen, continue to move slightly and reattach. In the water column they come from just below the low-water line down to about 119 m water depth before. At the Croatian Adriatic coast a depth range was observed up to 60 m. The animals live singly or in small colonies, often together with the also attached by a byssus modiolus modiolus kind barbatus ( Linnaeus, 1758). The highest observed population density there were 12 individuals per m2. The animals can be up to 15 years old and reach only 3 to 7 years, a (economic interest ) size of 5 cm. The animals are dioecious, however (about 2%) were also interestingly observed hermaphrodites to a small percentage. Also protandry seems to occur. The distribution area is the eastern Atlantic from the Algarve (Portugal ) to West Africa (Senegal ), and the Mediterranean Sea.
Economic Importance
In the Mediterranean Sea, Noah's Ark shell is collected locally and eaten. However, the economic significance is low because the population densities are relatively small.
System
According to the variability of body shape and color, there are a large number of names for Noah's ark. In total there are over 20 synonyms for this species