Atryma

Atryma is a genus of extinct brachiopods, marine invertebrates that lived during the Paleozoic Era. These fossils are typically found in the Devonian period deposits. Atryma shells are characterized by their spiraled internal structure, a feature that distinguishes them from many other brachiopod genera. The external shell often exhibits radial costae, which are rib-like projections, though their prominence can vary.

Brachiopods like Atryma are often referred to as "lamp shells" due to the resemblance of some species to ancient oil lamps. They were sessile organisms, meaning they attached themselves to the seafloor or other substrates. Atryma likely lived in shallow marine environments, filtering food particles from the water. The fossil record of Atryma provides valuable insights into the diversity and evolution of brachiopods during the Devonian, a period known for its abundant marine life. Studying Atryma helps paleontologists understand ancient ecosystems and the environmental conditions of the time. Their presence in different geological formations allows for biostratigraphic dating and correlation of rock layers.