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ABSTRACT
The scanilepiform ray-finned fish Fukangichthys longidorsalis, from the Middle Triassic non-marine Kelamayi Formation of Xinjiang, China, was previously described incompletely, with many of its morphological characteristics unnoticed or misidentified. This study provides a revision of this problematic taxon based on an extensive reexamination of the original fossil material. Newly recognized anatomical information includes a plate-like quadratojugal, a triangular dermohyal, a wedge-shaped angular, two infraorbitals, three supraorbitals, fringing fulcra on the pectoral fins, and conical, acrodin-capped teeth in the jaws. Results of a phylogenetic analysis confirmed Fukangichthys as a scanilepiform within the Neopterygii, and provided new insights into the evolution of early actinopteran fishes. Cosmoptychius, previously regarded as the oldest stem-group neopterygian, and Brachydegma, previously hypothesized to be the oldest halecomorph, are here reinterpreted as a stem-group actinopteran and a stem-group neopterygian, respectively. Additionally, Discoserra, previously hypothesized in a position close to the Holostei/Teleostei split, is now recovered in a clade with Ebenaqua, Bobasatrania and Platysomus gibbosus, and is therefore phylogenetically distant from crown neopterygians. As a consequence, fossil candidates for divergence time calibrations within the Actinopteri require reconsideration.
SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP
ACKNOWLEDGMENTS
We thank M.-M. Chang for constructive suggestions, M. I. Coates, M. Friedman, L. Cavin, A. López-Arbarello, and an anonymous referee for helpful comments on an early version of the manuscript. We thank M. Richter and J. Maisey for access to comparative fossil material in Natural History Museum (London) and American Museum of Natural History (New York), respectively. This work was supported by the National Natural Science Foundation of China (NSFC grants 40902010 and 41272002).
Handling editor: Matt Friedman.