Edmontosaurus annectensEdmontosaurus annectens (meaning "connected lizard from Edmonton"), often colloquially and historically known as the Anatosaurus (meaning "duck lizard"), is a species of flat-headed saurolophine hadrosaurid dinosaur from the late Maastrichtian age at the very end of the Cretaceous period, in what is now western North America. Remains of E. annectens have been preserved in the Frenchman, Hell Creek, and Lance Formations.
Timeline of hadrosaur researchThis timeline of hadrosaur research is a chronological listing of events in the history of paleontology focused on the hadrosauroids, a group of herbivorous ornithopod dinosaurs popularly known as the duck-billed dinosaurs. Scientific research on hadrosaurs began in the , when Joseph Leidy described the genera Thespesius and Trachodon based on scrappy fossils discovered in the western United States. Just two years later he published a description of the much better-preserved remains of an animal from New Jersey that he named Hadrosaurus.
EdmontosaurusEdmontosaurus est un genre éteint de grands dinosaures herbivores « à bec de canard » du sous-ordre des ornithopodes et de la famille des hadrosauridés. Ses fossiles ont été retrouvés dans des sédiments de l'ouest de l'Amérique du Nord datant de la fin du Campanien jusqu'à la fin du Maastrichtien au Crétacé supérieur, il y a entre 73 et . C'est l'un des derniers dinosaures non-aviens à avoir vécu aux côtés de Triceratops et de Tyrannosaurus peu de temps avant l'extinction Crétacé-Tertiaire.
TrachodonTrachodon (meaning "rough tooth") is a dubious genus of hadrosaurid dinosaur based on teeth from the Campanian-age Upper Cretaceous Judith River Formation of Montana, U.S. It is a historically important genus with a convoluted taxonomy that has been all but abandoned by modern dinosaur paleontologists. Despite being used for decades as the iconic duckbill dinosaur, the material it is based on is composed of teeth from both duckbills and ceratopsids (their teeth have a distinctive double root), and its describer, Joseph Leidy, came to recognize the difference and suggested limiting the genus to what would now be seen as ceratopsid teeth.
HadrosaurusHadrosaurus (Grec : ἁδρός, hadros + σαυρος, sauros = lézard robuste) est un genre douteux de la famille des hadrosauridés, ou « dinosaures à bec de canard ». En 1858, un squelette d'un spécimen du genre est découvert en Amérique du Nord et devient le premier squelette de dinosaure jamais reconstitué. vignette|centre|L'atelier de Benjamin Waterhouse Hawkins à Central Park en 1868, avec sa reconstitution du squelette d’Hadrosaurus (auquel il attribuait un crâne proche de celui d'un iguane).
