Meeting Abstract
23.3 Saturday, Jan. 4 14:00 Getting inside the heads of Cretaceous-Paleogene teleosts: new morphological and functional data from the exceptional fish fossils of the English Chalk and London Clay CLOSE, RA*; BECKETT, H; MACLEOD, N; JOHANSON, Z; FRIEDMAN, M; University of Oxford roger.close@gmail.com
Three-dimensional-preserved fossil fishes from the Late Cretaceous (Cenomanian-Campanian) English Chalk and Eocene (Ypresian) London Clay have been known and collected for nearly two centuries. Despite excellent preservation, fishes from these exceptional localities have received scant attention outside of monographs that are all now more than 50 years old. Now, however, computed tomography (CT) scanning has permitted us to extract considerable new morphological and functional information from dozens of fossil fishes from these deposits. Fishes from both the English Chalk and London Clay preserve features like articulated gill skeletons and inflated braincases, character-rich anatomical regions that are generally poorly preserved in flattened specimens found in lithographic limestones or shales. In addition to providing a wealth of anatomical information on early representatives of many major eurypterygian lineages, CT scanning permits the acquisition of functional and ecomorphological measurements previously only accessible from neontological datasets. By harnessing the mature framework that has been developed for quantifying feeding ecomorphology in fish, we are able to critically test previous hypotheses relating to changes in functional diversity between the Mesozoic and Cenozoic in acanthomorph (spiny-finned) teleosts, one of the most successful radiations of modern vertebrates. Using ground-truthed measures of performance, we are able to show a substantial increase in acanthomorph cranial functional diversity between the Late Cretaceous and Eocene, corroborating inferences drawn from sparse cranial landmark constellations applied to taphonomically flattened material from other localities.
