NSFGEO-NERC: The first actinopterygian adaptive radiation: integrating fossils, function and phylogeny to illuminate innovation in a post-extinction..

Ancient mass extinctions resulted in the loss of many species but also provided new opportunities for surviving groups. Study of these events is central to both understanding the origin of today's biological diversity as well as contextualizing the threats it faces from environmental change. This work focuses on a major interval of crisis and recovery that took place around 360 million years ago: the Devonian/Carboniferous extinction.

This study will determine the impact of this event on the early history of ray-finned fishes, key components of today's aquatic ecosystems and a major commercial resource. The project will provide training at high school, undergraduate, graduate, and postgraduate levels, and develop educational materials for wide audiences, including those underrepresented in STEM fields.

Outreach includes a module for high-school students at the University of Michigan, programs at three museums with a combined annual attendance of greater than 500,000, and resources for use in local communities.

This work will examine the role of the Devonian/Carboniferous extinction (359 Ma) in precipitating an apparent explosion of diversity among actinopterygians, setting the stage for the group's dominance throughout the remainder of the Phanerozoic. The project will combine microCT, functional anatomy, 3D morphometrics, combined-evidence phylogenetic inference, and evolutionary comparative methods to Devonian and Carboniferous (419-299 Ma) actinopterygians.

The project team will: (i) quantify discrete functional innovations, biomechanics, and shape for mandibles to test for increased functional and morphological diversity following a mass extinction; (ii) integrate anatomical, stratigraphic, and molecular data in a Bayesian framework to develop an inclusive hypothesis of early actinopterygian relationships and test hypotheses about the timing of evolutionary divergences and patterns of survival across the extinction boundary; and (iii) combine functional and morphological data with new phylogenetic hypotheses within a comparative framework in to test for shifts in evolutionary rate and mode among actinopterygians associated with the Devonian/Carboniferous extinction.