Brachiopods - Tongue Shells and Lamp Shells

Lang de

The trivial names are deceiving – their similarity with a Roman oil lamp accounts for the wrong assignment of terebratulid brachiopods to clams and mussels. But brachiopods are no mollusks at all, but bivalved sea creatures with tentacles that belong to a separate phylum. Their ventral and dorsal valves are opened and closed by a complicated system of muscles. Brachiopods without hinges (the former Inarticulata, now Linguliformea) have phosphatic shells and live within muddy seafloors or as epizoans. Brachiopods with hinges (formerly Articulata, now Rhynchonelliformea) have calcitic shells and live attached by a flexible stem. Compared to the Tethyan Triassic the brachiopod diversity of the Muschelkalk is very low. However, the few Muschelkalk species can be extremely abundant in certain shell beds. The small microconch posthorn tubes are distantly related to brachiopods.