My primary research interests associated with NAI are: 1) the causes and timing of the end-Permian mass extinction, particularly assessing the possibility of an extra-terrestrial impact; 2) processes of biotic recovery and rediversification following mass extinction, with particular reference to the Early Triassic; 3) Ecological and developmental aspects of the Cambrian radiation, particularly the role of developmental innovations.

My work on the end-Permian mass extinction stems from my interest in evolutionary innovations, and particularly in those following the great mass extinctions. These events are classically seen as generators of evolutionary novelty, and I am interested in the patterns of survival and rediversification, how rapidly these changes occur, and how ecological assemblages re-form. Although I am interested in the recoveries after all of the major mass extinctions, my own work has focused on the Early Triassic, and particularly on gastropods. Gastropods exhibit an interesting pattern in which some lineages disappear from the fossil record during the late Permian, prior to the mass extinction, and reappear during the recovery phase. This Lazarus phenomenon provides some important clues to the relative importance of continuing environmental disturbance vs. ecological retardation during biological recoveries. Together with colleagues at the Santa Fe Institute, I am also developing models of biotic recovery that we can test with data from the fossil record.

Laboratory/Facilities:
The National Museum of Natural History collections are the largest in the world, totaling over 124 million lots, of which 35% are under the aegis of the Department of Paleobiology. Noteworthy collections include an incomparable collection of specimens of the Middle Cambrian Burgess Shale, and Charles Walcott's historical collection of stromatolites. Full laboratory facilities are available, including microscopes, digital imaging, and a sophisticated morphometrics lab.

Collaborators:
Peter Ward, University of Washington. Others all within the MIT/Harvard node.