Mark Allen Norell (born July 26, 1957) is an American vertebrate paleontologist. He is currently the chairman of paleontology and a research associate at the American Museum of Natural History. He is best known as the discoverer of the first theropod embryo and for the description of feathered dinosaurs. Norell is credited with the naming of the genera Apsaravis, Byronosaurus, Citipati, Tsaagan, and Achillobator. His work regularly appears in major scientific journals (including cover stories in ...