Articulata (Brachiopoda)

Onniella spp.

The Articulata are closed bearing ( articulate ) brachiopods ( Brachiopoda ) with kalzitischer shell. The lock edge is formed by the edges of the rear inter-area ( the shell region between vertebrae and lock edge ). The castle consists usually of a pair of ventral ( seated at the castle door ) teeth and a pair of dorsal ( seated at the Armklappe ) tooth pits. The trays are moved with a working against each other apparatus of Öffnermuskeln ( Diductores ) and sphincter muscles ( adductors ). Pedicle muscles ( Adjustores ) control the stem.

The Articulata are by far the largest group of brachiopods and contain around 90 % of the 4500 species, few of which occur but tart. However, due to their calcareous shells are well preserved as fossils, the taxonomic subdivision depends on the shape of the shells and castle formations. For the definitions of the era of the Geological time scale within the Articulata have passed since the Cambrian stratigraphy of great importance.

System

In order to group the results summarized in the Articulata brachiopods better together with newly discovered fossil species of the classes Chileata, Obolellata, Kutorginata and Strophomenata, the sub-tribe Rhynchonelliformea ​​was introduced in paleontology recently. As recent, so still existing species of Articulata the orders are

• Rhynchonellida
• Terebratulida
• Thecideida