Vertebrate morphology and evolution is a major focus of my lab with special interest in archosaurs. Scores of dinosaurs from all major groups (ornithischians, sauropodomorphs, theropods) including early birds have been studied in collections or unearthed as new discoveries from many continents. Flying reptiles (pterosaurs), crocodilians, turtles, bony fish, and a multituberculate mammal are also under study.
African faunas from Jurassic and Cretaceous horizons are of particular interest, because the history of African faunas during the Mesozoic is sketchy at best. Current work will unveil an armor-free upright crocodilian, an early quadrupedal armored dinosaur, sauropods of many kinds, a small raptor skeleton that used its forelimbs to dig up prey, and new theropods including a new species of Spinosaurus. Bony fish under study include a new giant polypterid and a small freshwater ichthyodectiform.
Dinosaur “mummies” preserving soft tissue (integument) renderings are under study from end-Cretaceous rocks in Wyoming that include the duckbill Edmontosaurus and Tyrannosaurus. Body frills and spikes as well as hooves are under macro- and molecular study to understand how these such vestiges are preserved.
Nonvertebrates (invertebrates) are also of interest, including a new swimming crab (decapod) discovered in a Late Cretaceous pond deposit in the Kem Kem Group in Morocco and a new scarab beetle from mid Cretaceous age beds in Niger.
Functional studies focus both on testing the functional parameters of particular taxa, such as the aquatic capabilities of Spinosaurus, to large-scale theoretical considerations of how vertebrate function evolves. “Macromodules” identify major functional partitioning (or sequestration) of the original unified (integrated) craniate functional design. Once sequestered, the research is demonstrating, macromodules are rarely, if ever, reversed in the course of vertebrate evolution.
Generating programs and/or databases to facilitate the understanding and curation of vertebrate morphologic, phylogenetic and taxonomic data are ongoing. FossilScope is a freeware program in development to compile and make available the fossil evidence and digital manipulations that underpin vertebrate skeletal and skeletal-muscle restorations. CharcaterSearch and TaxonSearch, similarly, compile and make accessible character data in phylogenetic analyses and historical and current taxonomic definitions, respectively, using archosaurian reptiles as prototypes.
Discovery of the Holocene archaeological site Gobero in 2000 marked the beginning of my archaeological research into by far the richest archaeological site in all of the Sahara during Early and Middle Holocene time (~10,000-5,000 BP) during the African Humid Period. More than 100 burials were excavated and thousands of artifacts and faunal remains were collected and set into a detailed geologic and chronologic setting has revealed a unique archaeological story: sustained, sedentary hunter-fisher-gathering supported by freshwater springs in a Green Sahara.
Lab & Field Work
I joined the faculty of the University of Chicago in 1987, developing in stages what has become the Fossil Lab, located just off campus in Washington Park. In the 1950s the university closed its Walker Museum, thereby eliminating its paleontology lab and dispersing its fossil and recent collections. The lab and collections needed rebuilding, if one was to engage in a serious field program.
My field work began in the foothills of the Andes in Argentina in 1988, where I discovered skeletons of the earliest dinosaur, including dog-sized Eoraptor ("dawn raptor") and Eodromaeus ("dawn runner"). We dated (radiometrically) those horizons for the first time (231.4 Ma) and described the mixed archosaur-synapsid fauna and paleoenvironments that once existed in southern Pangaea at the dawn of the dinosaur era (early Late Truassic).
Later, on expeditions to India, my teams discovered fossils of a new dinosaur, Rajasaurus (“princely reptile”), the first predatory dinosaur skull for India. In a remote corner of the Gobi Desert in Inner Mongolia (China), we discovered a herd of subadult ornithomimid dinosaurs, named Sinornithosaurus (“Chinese bird mimic”), that died in their tracks, mired in mud 90 million years ago. To this day, it comprises the only provable instantaneous population of dinosaurs ever discovered. On an expedition to Tibet at an elevation of 13,000 feet, we rediscovered a site that yielded an as yet unnamed, new long-necked dinosaur, fossilized originally on an island in the Tehthan Sea.
Starting in the early 1990's, I launched expeditions to the Sahara to beds of Jurassic and Cretaceous age, excavating more than 100 tons of fossils and bringing to light a menagerie of new species including long-necked herbivores like Nigersaurus (“Niger reptile”), meat-eaters like Afrovenator (“African hunter”) and Rugops (“rough face”), and the bizarre huge-clawed fish-eaters Suchomimus (“crocodile mimic”) and Spinosaurus ("spined reptile"). Other discoveries include the world's largest crocodile, the 40-foot-long “SuperCroc” (Sarcosuchus), the fanged, horned “BoarCroc” (Kaprosuchus), and a pterosaur (winged reptile) with a 15-foot wingspan.
In 2000 I discovered Gobero, the richest archaeological site in the Sahara. Dating to a time before the pyramids, the site documents cultures that thrived for millennia as hunter-fisher-gatherers. In 2006 I excavated the most posed burial in all of prehistory —a triple burial of a mother and two children holding hands. It was dubbed the “Stone Age Embrace.”
Engagement at all levels —students, the general public, southside neighborhoods, foreign countries— is intertwined with my research, affecting the kinds of classes I teach, my efforts to bring STEAM pathways to teens on the southside of Chicago, and a long-term plan to found new national museums and study programs in Niger (NigerHeritage). I have penned stories in National Geographic and have participated in 15 documentaries on my research. Engagement recognition includes Chicago Tribune's Teacher of the Year award (1993), Chicago magazine’s Chicagoan of the Year (1996), and the Presidential Award for Excellence in Science, Mathematics and Engineering Mentoring (2009).