B.S., University of California at Santa Cruz, Earth and Planetary Sciences, 1976.
M.S., Paleobiology, University of Rochester, Geological Sciences, 1979.
Ph.D., Paleobiology, The Johns Hopkins University, Earth and Planetary Sciences, 1984.

Predoctoral Fellow, Paleobiology, Smithsonian Institution, 1982.
NATO Postdoctoral Fellow, British Museum (Natural History), 1984.
Chair, Association of North America Paleontological Societies.
Associate Professor (Adjunct), Biological Sciences, University of Illinois at Chicago, 1994.

Evolution and ecology of cheilostome bryozoans

Evolution and ecology of cheilostome bryozoans, particularly the relationships of colonial growth and form/evolutionary paleoecology and the resolution of large-scale patterns in the fossil record/angiosperm diversification and Cretaceous floristic trends.

Research focuses on the roles of different modes of growth in large scale patterns of cheilostome bryozoan evolution, environmental distribution and ecology. My previous work on comparative skeletal ontogenies of zooids within colonies recognized characteristic zooid budding patterns of encrusting cheilostomes. More recently I have synthesized the overriding evolutionary trends in predominant modes of growth in this group, documenting a persistent evolutionary transition in which one mode of growth is supplanted by another during the past 100 million years. In an environmental context, this work has also provided a novel test of paleoenvironmental studies of other groups of marine benthos in which onshore origin was followed by expansion into offshore, deeper water marine environments.

A related research problem involves re-evaluating the role of competition in large-scale evolutionary replacements such as dinosaurs versus mammals or brachiopods versus clams. This work on cheilostome and cyclostome bryozoans has produced surprising results-the pattern of replacement differs when species, genera or families are used as the basis for the analysis.

Collaborative research (with P. R. Crane) examines large-scale floristic patterns during the radiation of angiosperms. We have employed trend surface analyses to demonstrate a striking latitudinal shift (from tropical to boreal) in the pattern of increasing angiosperm dominance through the Cretaceous. This work is part of more comprehensive synthesis of paleolatitudinal and temporal trends in the apparent diversity of all Cretaceous land plants. We have also attempted to clarify the rate and magnitude of angiosperm radiation using the parallel fossil records of leaves and pollen/spores, to provide a deductive test of evolutionary tempo during the diversification of a major group of organisms.

Morphometric analyses of New Zealand bryozoans (Lidgard and Buckley, 1994) indicate that traditional taxonomic practices are inadequate in their ability to distinguish species level taxa in Adeonellopsis, and quite possibly in cheilostome bryozoans as a whole. The implications of this result are that currently recognized species may underestimate cheilostome diversity by a factor of two, three or more.