Orthida

Hesperorthis martinsonii ( Bassett, 1974)

Orthiden ( Orthida ) are an extinct taxon of brachiopods ( Brachiopoda ) with a straight edge and a castle impunctaten or endopunctaten shell. They form together with the Protorthida, Rhynchonellida, Atrypida, Spiriferida, Athyridida and Terebratulida the taxon Rhynchonellata that counts its part to the lower trunk of the Rhynchonelliformea ​​.

Features

Your body usually consists of biconvex valves. Orthiden have no real Armgerüst, only small support plate ( Brachiophoren ) can be formed. The group was first named in 1932 by Schuchert and Cooper.

System

The Orthiden divided into four Untertaxa, which are broken down after formation of the Delthyriums, the Spondyliums and dotting the shell:

• Billingsellacea
• Clitambonitacea
• Orthacea
• Enteletacea or ( Dalmanellacea )