Lampshells may have been the most abundant animals, with numerous different species, living in and around the Silurian reefs. Leptaena were flat lampshell, with an upturned shell rim, that lay unattached on the sea floor.

A lampshell’s body is mostly enclosed in a bivalve shell like that of a modern clam or scallop, but the animal has a completely different appearance. Most lamp shells have a short foot (pedicle) that sticks out between the valves at the back and anchors the creature to the sea bed. Between the two valves is a coiled arm-like structure bearing many small tentacles. The arm pumps water into the shell and filters out plankton.