The Devonian is famous for the thousands of species of fish that developed 395 million years ago. In addition to fish, brachiopods also reached their zenith in number and diversity. Early brachiopods (mussels and clams), pelecypods (early oysters) and gastropods (snails), dominated the sea floors when the land was submerged by warm, shallow seas.
These bottom dwellers fed on food particles that they would filter out of the water. There are over 12,000 fossil species of brachiopods (and about 300 modern species). The abundance of species makes them useful for dating the rocks and associated fossils.
Evidence from Devonian supports the idea that the present continents were being united in a single continental mass called “The Old Red Sandstone Land Mass”, uniting Gondwana, Laurentia, and Baltica.
