The tactile experience of holding a fossil that’s millions of years old offers the most exciting and memorable way to learn! Add this to your fossil library and strengthen engagement and learning in your classroom!
This ribbed shell is a fossil of the order Rhynchonellida. These brachiopods have existed since the Ordovician period 485 million years ago. Their population was severely diminished during the Permian–Triassic extinction event 252 million years ago, but Rhynchonellida became the most abundant brachiopod group during the Mesozoic.
This group is identifiable by their deep ribbed surfaces and short hinges, which usually come to a point. These bivalves were the first to evolve teeth sockets, which help to align the two halves as they close and make it harder for a predator to open the shell by twisting the valves.
It is hypothesized that the radiating ribbed pattern helps regulate the flow of water in and out of the shell.
