9612880 Farlow In what morphological features, and at what taxonomic level, would tridactyl (three-toed) footprints likely vary across different groups of bipedal dinosaurs? Because we cannot observe footprint formation by living, non-avian dinosaurs, it is proposed to investigate these questions indirectly, through inter-related analyses of within-taxon and across-taxon morphological variability in: a) hindfoot and toebone proportions in dinosaurs and ground birds; b) footprint shape in ground birds; c) skeletal and "fleshy" foot proportions in crocodilians. Morphometric analyses of foot and footprint shape will be employed to address the question of how different footprints can be, and still have been made by the same kind of taxon and how similar prints can be, and yet have been made by different taxa. Each component of the project addresses a different aspect of the problem of interpreting the diversity of animals responsible for dinosaur fooprint faunas, and each addresses shortcomings I the other approaches. Together they will provide a theoretical framework upon which to base systematic interpretations of tridactyl dinosaur footprints. Results of these studies will be used to interpret the ichnotaxonomy of tridactyl dinosaur footprints from Early Cretaceous rocks of Texas.