Paul C. Sereno (1958–) is an American paleontologist currently at the University of Chicago. He has worked at many dinosaur dig sites, including those in South America, Asia, and Africa. Among his dinosaur accomplishments, he: discovered the first complete skull of Herrerasaurus; was responsible for excavating a giant Carcharodontosaurus in 1996; named the oldest-known dinosaur, the Eoraptor (with others) in 1993; and, in 1991, found the second oldest fossil birds, Sinornis (“Chinese bird”). He also named many new dinosaur fossils and rearranged the dinosaur family tree, reorganizing the ornithischians and naming the clade Cerapoda (formed from the ornithopods and marginocephalians).