BONY FISHES BASED ON OTOLITHS AND OSTEOLOGICAL REMAINS FROM THE OLIGOCENE OF LOUISIANA
This study concentrates on describing the Oligocene marine bony fishes from Louisiana based on osteological remains and otoliths (earstones) with the otoliths providing the vast majority of the data. Before the examination of teleostean otoliths, the Oligocene marine bony fishes in Louisiana were virtually unknown and limited to a few taxa based on isolated skeletal remains (mainly teeth). The otoliths have allowed for an in-depth analysis and description of the Oligocene bony fish assemblage. Approximately 1200 teleostean otoliths and skeletal remains have been collected from four Oligocene localities in Louisiana and represent at least 19 families and 27 taxa of actinopterygians. Major constituents of the teleostean assemblage based on otoliths include clupeids (herrings), congrids (conger eels), ophiidids (cusk eels), bregmacerotids (codlets), sciaenids (drums), and paralichthyids (flatfish). Unfortunately, all of the localities have very shallow paleowater depths (probably less than 40 meters), which limits the diversity of the bony fishes present. Sciaenids are the most abundant representatives in the assemblage and include Sciaena pseudoradians, Aplodinotus distortus, and Aplodinotus gemma, all extinct drums. All of the taxa based on otoliths indicate fish from shallow marine to possibly estuarine conditions that preferred soft substratum in a tropical to subtropical climate.