Mucrospirifer thedfordensis - Middle Devonian brachiopod fossil from Ontario, Canada

$ 4.50

Mucrospirifer thedfordensis (Shimer & Grabau, 1902) 

Brachiopods, sometimes called lamp shells, are filter feeders and are attached to the sea floor by a fibrous pedicle that extends from a hole in the pedicle valve. The “wings” of spirifers possibly stabilized the shell in the sea floor sediments. 

In order to feed, brachiopod shells had to be open. The lophophore, a combination of a feeding and respiratory organ, had a number of tiny tentacles that created a current to allow filter feeding. It was supported by two arms attached to the interior of the brachial valve. This was an evolutionary  disadvantage when compared to bivalve molluscs, which could feed through siphons with the shells tightly closed.

The first brachiopods appeared in the early Cambrian. Some brachiopods survived competition from molluscs, today generally living in very deep or cold water.

These nicely preserved specimens were collected from the Middle Devonian Widder Formation at Thedford, Ontario, Canada. Both sides are shown. 

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