BRACHIOPODA HAVE/ARE

Bilaterally symmetrical
Large and complex lophophore
Calcareous bivalve shell enclosing all of the body except stalk
U-shaped gut
Open blood system with heart
Sexes are usually separate
Marine

Brachiopoda diagram of body parts

Their chaetae are used to act as filters. They feed mainly on detritus and algae. The ciliated lophophore creates a current bringing in micro-organisms and food particles which are trapped on the mucous and passed by the cilia down to the mouth.

They are found from intertidal to 7 500 m deep in cool-temperate - cool regions.

Terebratulina cautserpentis, lamp shell, brachiopod

Brachiopoda are commonly known as the lamp shells. There are about 26 000 fossil species dating from the Cambrian onwards, but only about 350 species survive today.

Externally they are similar to the bivalve molluscs, see Terebratulina caputserpentis left.

The pedicle or ventral valve is usually larger than the brachial or dorsal valve (see right). All living species are less than 10 cm long, though fossils can reach 30 cm long.

They attach to the surface by a stalk or pedicle, usually in a position to gain maximum benefit from the water currents.