Strophomenacea

Strophomenacea is an extinct order of brachiopods that lived during the Paleozoic Era, from the Cambrian to the Permian periods. These marine invertebrates are characterized by their biconvex shells, meaning both the dorsal and ventral valves are convex. A distinguishing feature of strophomenaceans is the presence of punctae, small pores that penetrated the shell material. The internal structure of the shell often contained fibrous layers. Strophomenaceans exhibited a wide range of shell morphologies, from flattened to highly arched. They are generally divided into two suborders: Strophomenidina and Productidina. Strophomenidines typically had a more impunctate shell, while productidines possessed prominent spines. These brachiopods were often sessile, attaching themselves to the seafloor or other substrates. Fossil evidence indicates they inhabited various marine environments, from shallow to deep waters. Their shells are common in Paleozoic sedimentary rocks, providing valuable insights into ancient marine ecosystems and biogeography. The decline of strophomenaceans towards the end of the Paleozoic may be linked to environmental changes.