Ancient Australian graptolite faunas reveal evolution of marine life.
The article describes three different groups of ancient sea creatures called graptolites that lived in Australia during the Ordovician period. These groups are the Anisograptid, Dichograptid, and Diplograptid faunas. The Dichograptid Fauna includes two sub-groups, Tetragraptus-Didymograptus and Isograptid. The Diplograptid Fauna includes Glyptograptus-Amplexograptus and Leptograptus-Orthograptus sub-groups. The Diplograptid Fauna disappears in the Silurian period, making way for the Monograptid Fauna, which lasts until the Devonian period.
