Gryphus vitreus Seashell Topical Brachiopod Lamp Shell

Gryphus vitreus mm 20-25 Seashell Topical Brachiopod Lamp Shell.
Family: Terebratulidae.
Common name: Two Layer Shell.
Syn.  Anomia vitrea, Liothyris vitrea, Terebratula vitrea.

It should be noted for all bivalves that the two valves may have been glued or remained closed due to the dried ligament and therefore the item appears as a single piece. Therefore, we are not responsible for any damage caused to the shell to try to badly separate the pieces.

The phylum of brachiopods consists of marine invertebrates, benthic, sessil, sospensivorous and with bilateral symmetry.
The plane of symmetry is perpendicular to the commissure of the valves, which are divided into a peduncular valve (or ventral) and a brachial (or dorsal), generally smaller. They are inequivalves and equilateral.
They look, similar to the phylum of bivalve molluscs, is simply due to convergent evolution, having no direct relationship with them.

Nowadays these animals are scarce because they live in "refuge areas", ie areas with low population and competition. They were however very common in the Paleozoic, then, following the mass extinction at the Permian-Triassic, have migrated into deeper waters.