Current research includes plant-animal interactions, the origin of land plants, and symbioses. Current research includes use of isotopic methods to investigage plants' response to the environment. Systematic biology and morphology of amphibians with emphases on osteology of anurans. Current research includes phylogeny of frogs including those known from the fossil record. Paleontology and paleoecology of the Upper Carboniferous and Permian invertebrates.
Current research includes systematics and paleoecology of fossil chaetetid sponges.
Ph.D., City University of New York, 1976. Mesozoic and Cenozoic fishes. Current research includes relationships of higher teleost fishes, fossil and recent. Preparator of vertebrate fossils. Current research interests include the Niobrara Chalk beds of Kansas and their fauna.