Arcoida

Anadara

The Arcoida are an order of mussels ( Bivalvia ), which is provided infra class Pteriomorphia within the Autolamellibranchiata. It is an exclusively occurring in the sea mussel group. The oldest Arcoida are already known from the Lower Ordovician.

Characterization

The housing of the Arcoida are often oval and equivalve, rare aberrant. The shell is exclusively aragonitisch with predominantly kreuzlamellaren and prismatic microstructures. The lock bar is multifaceted and can also be reduced. The castle itself toothless or taxodont, or even other types of teeth occur. The sphincters are uniform or only slightly non-uniform. The foot is usually big and strong.

Way of life

The Arcoida are exclusively marine living mussel, which are usually attached to the substrate by means of organic linen. They usually live on or only half buried in the sediment.

System

The Arcoida include according to the latest classification of Bieler & Mikkelsen (2006) two superfamilies, of that there is an extinct superfamily:

• Superfamily † Cardioloidea Fischer, 1886
• Superfamily Arcoidea Lamarck, 1809, inter alia, to the the ark shells ( Arcidae ) belong. Sea Almond ( Glycymeris Glycymeris )