Ordovician animals

Pentamerida is an order of biconvex, impunctate shelled, articulate brachiopods that are found in marine sedimentary rocks that range from the Middle Cambrian through the Devonian.

Onychopterellidae are an extinct family of eurypterids. The family is the only family classified as part of the superfamily Onychopterelloidea. Genera included are Onychopterella and Tylopterella.'''' Alkenopterus was once included in the Onychopterellidae but has since been classified in its own family, Alkenopteridae.''''