A new species of Lasalichthys (Actinopterygii, Redfieldiiformes) from the Upper Triassic Dockum Group of Howard County, Texas, with revisions to the genera Lasalichthys and Synorichthys

ABSTRACT

A new species of redfieldiiform fishes, Lasalichthys otischalkensis, sp. nov., is described based on new, three-dimensionally preserved specimens from the Upper Triassic Dockum Group of Howard County, western Texas. Lasalichthys otischalkensis is diagnosed by a combination of unique traits found in the skull, including shape of maxilla, shape of preoperculum and associated cheek bones, pattern and articulation of bones in the snout, and patterns of sensory line canals in the dermal skull bones. Specimens of this new species display novel patterns in the sensory line canals of the skull that have never been observed in any other redfieldiiform. Examination and comparison of specimens of Lasalichthys and Synorichthys from the Upper Triassic Chinle Formation and Dockum Group indicates that these taxa are only distinguishable at the species level, and Synorichthys is placed into synonymy with Lasalichthys, based on comparison of diagnostic morphological characters. Lasalichthys otischalkensis represents one of the oldest redfieldiiform taxa in North America.

ACKNOWLEDGMENTS

I thank the following individuals and their respective institutions for access to specimens for this study: J. Maisey and A. Gishlick (AMNH); R. Irmis, C. Bussian, and M. Getty (UMNH); S. Lucas (NMMNH); A. Millhouse and M. Brett-Surman (NMNH); A. R. C. Milner (St. George Dinosaur Discovery Site at Johnson Farm, St. George, Utah); M. Brown and C. Sagebiel (TMM); L. Grande and W. Simpson (FMNH); E. Bernard (NHMUK); A. Pradel (MNHN); and S. Pierce and J. Cundiff (MCZ). I thank the University of Kansas Biodiversity Institute and the Davis Lab at St. Cloud State University for laboratory space and equipment for specimen preparation and examination. I thank H.-P. Schultze and W. L. Smith for constructive suggestions for the improvement of the manuscript. I thank A. Heckert and J. Martz for information regarding the geology of the Dockum Group in Howard County. National Science Foundation Doctoral Dissertation Improvement Grant (DEB 1502005) supported this research.