Pectinoida

Scallop ( Pecten jacobaeus )

The Pectinoida ( " scallop -like " ) are an order of mussels ( Bivalvia ) from the infra class Pteriomorphia within the Autolamellibranchiata. It is an exclusively marine living mussel group. The oldest Pectinoida already appear in the Silurian.

Characterization

The housing of the Pectinoida are always more or less equivalve ( Pteroidea ) or equivalve ( Pinnoidea ). The shell is made of an inner layer with aragonitisch, pearl ring microstructures and an outer calcitic layer composed of simple prisms. For some groups, these calcitic layer is missing. The castle is largely reduced. Also, the front sphincter is generally reduced more or less clearly. Most forms have a fine linen. One foot is developed and remains so throughout the ontogeny obtained ( in contrast to the Ostreoida ). At the edge of the mantle tentacles are formed.

Way of life

The Pterioida are exclusively marine bivalve molluscs, which are usually attached to the substrate by means of organic linen, are cemented with the right door or exposed on the sediment.

System

The order Pectinoidea is not yet generally accepted, but is sometimes nor to the order Ostreoida provided. According to recent phylogenetic studies this order is merely a superfamily of Pterioida. Phylogenetic relationships of Pterioida, Limoida and Pectinoida are not yet clear. After Bieler & Mikkelsen (2006) the order Pectinoida includes four ( recent ) About Families with 6 families.

• Superfamily Pectinoidea Rafinesque, 1815 Family Pectinidae Rafinesque, 1815 (eg scallops, Chlamys genus with the species of the Icelandic scallop ( Chlamys islandica ) and the colorful scallop ( Chlamys varia), the little scallop and scallop ( Pecten jacobaeus ) )
• Family EntoliidaeTeppner, 1922
• Family Spondylidae Gray, 1826
• Family Propeamussiidae Abbott, 1954

• Family Anomiidae Rafinesque, 1815 Saddle shell ( Anomia ephippium )

• Capiz Shell ( Placuna placenta )

• Family Plicatulidae Watson, 1930

• Family Dimyidae Fischer, 1887

In addition there are 5 exclusively fossil superfamilies:

• Superfamily † Pterinopectinoidea Newell, 1938
• Superfamily † Aviculopetinoidea Meek & Hayden, 1864
• Superfamily † Pseudomonotoidea Newell, 1938
• Superfamily † Monotoidea Fischer, 1887
• Superfamily † Halobioidea Kittl, 1912