Spiriferida

Eospirifer radiatus ( Sowerby, 1835)

Spiriferida ( spiriferids ) are an extinct taxon of brachiopods ( Brachiopoda ) with a straight, usually long lock edge, a mostly impunctaten bowl and a spiral ( = helicopegmaten ) Armgerüst. They form together with the Protorthida, Orthida, Rhynchonellida, Atrypida, Athyridida and Terebratulida the taxon Rhynchonellata that counts its part to the lower trunk of the Rhynchonelliformea ​​.

Features

Your case is made of strong biconvex valves. It is characterized by a large inter-area in the Ventralklappe, the Delthyrium is open or provided with separate Deltidialplatten. The spiral Armgerüst may be directed to the rear side or diagonally. In the history of the earth they come from the Silurian up Jura. Especially in the Paleozoic spiriferids have a good at least for the rough age speech biostratigraphic conductance. The group was first named in 1883 by scales.

System

The spiriferids divided into five Untertaxa after training ( striations ) are broken the lock extension, puncturing and ribbing of the shell:

• Cyrtiacea
• Suessiacea
• Spiriferacea c1: Sine and ribbed bead
• C2: Sine and bead unberippt