New actinopterygian taxa from the Mid-Pennsylvanian Garrard Quarry, Indiana, U.S.A., and their implications in early ray-finned fish evolution during Late Paleozoic era

During the Carboniferous, marine ecosystems recovered from the Devonian mass extinction events. Some studies suggest that the aquatic vertebrate ecosystem had fully recovered in Early Carboniferous, followed by a long interval of stability. The rarity of Pennsylvanian (Late Carboniferous) localities was sometimes cited as the factor. Thus, it is necessary to study vertebrate fossils from multiple, appropriate localities. Here, three new actinopterygian taxa from the Garrard Quarry, Indiana, U.S.A., are described. A comprehensive parsimony phylogenetic analysis using PAUP was conducted based on 256 morphological characters and 104 fish taxa, 15 of which are included in any phylogenetic analysis for the first time. Analysis of this matrix led to the recovery of a clade of Permo-Carboniferous fishes, as the sister group of more derived actinopterygians (e.g., Amia, Chondrosteus). This hypothesis sheds new light on the evolution of early Actinopterygii. The monophyly of the Permo-Carboniferous fish group is supported by several synapomorphies such as the blunt rounded snout in lateral view, dorsal dermosphenotic contacts the nasal bone, coronoid bones with single tooth row, anteroventral process on the subopercle, evenly segmented pectoral fin rays from proximal to distal, small and spine shaped fringing fulcra placed between the terminal segments of marginal rays, and caudal fin with short epichordal rays.