Devonian, declining during the Pragian but rising again during the following Emsian, which was followed by a decline in diversity during middle-Late Devonian. The diversity of the group was consistently low but stable during the Carboniferous, slightly decreasing going into the Permian. The youngest records of the group are isolated scales and fin spines from Middle-Late Permian strata in the Paraná Basin of Brazil. References Further reading External links Acanthodii taxonomy †Ischnacanthiformes taxonomy †Climatiiformes taxonomy †Acanthodiformes taxonomy Acanthodopsis wardi Prehistoric fish classes Teleostomi Permian fish Silurian fish Silurian first appearances Permian extinctions Taxa named by Richard Owen Paraphyletic groups