During the Devonian, the molluscan class of Cephalopoda diversified, notably a new subclass of Ammonoidea took over from the Early Paleozoic subclass Nautiloidea as the dominant cephalopod subclass. While nearly all Early Paleozoic nautiloids show gently curving sutures, the Late Paleozoic ammonoid suture lines developed the diverse goniatitic fold pattern with numerous pointed lobes and rounded saddles. This group of goniatites ranged from Devonian to Permian.

Rugose and tabulate corals continued to make major contributions to the formation of Late Paleozoic reefs.

Rugose corals have radial septa and commonly occurred as solitary animals. Solitary rugosans are often referred to as "horn corals" because of their characteristic shape, some reaching nearly a meter in length. However, some species of rugose corals could form mounds or large colonies.

Tabulata corals receive their name from horizontal internal partitions known as tabulae. Most tabulates were colonial with some forming substantial reefs. Tabulate corals and rugose corals went extinct at the end of the Permian as victims of the greatest mass extinction ever.