SecernosaurusSecernosaurus (meaning "severed lizard") is a genus of herbivorous dinosaur. Secernosaurus was a hadrosaur, a "duck-billed" dinosaur which lived during the Late Cretaceous. Secernosaurus and its close relatives lived in South America, unlike most hadrosaurs, which lived in the Laurasian continents of Eurasia and North America. It has been suggested that the ancestors of Secernosaurus crossed into South America when a land bridge temporarily formed between North and South America during the Late Cretaceous and allowed biotic interchange between the two continents.
ProsaurolophusProsaurolophus (ˌproʊsɔːˈrɒləfəs; meaning "before Saurolophus", in comparison to the later dinosaur with a similar head crest) is a genus of hadrosaurid (or duck-billed) dinosaur from the Late Cretaceous of North America. It is known from the remains of at least 25 individuals belonging to two species, including skulls and skeletons, but it remains obscure. Its fossils have been found in the late Campanian-age Upper Cretaceous Dinosaur Park Formation in Alberta, and the roughly contemporaneous Two Medicine Formation in Montana, dating to around 75.
GorgosaurusGorgosaurus (ˌɡɔːrɡəˈsɔːrəs ; dreadful lizard) is a genus of tyrannosaurid theropod dinosaur that lived in western North America during the Late Cretaceous Period (Campanian), between about 76.6 and 75.1 million years ago. Fossil remains have been found in the Canadian province of Alberta and the U.S. state of Montana. Paleontologists recognize only the type species, G. libratus, although other species have been erroneously referred to the genus. Like most known tyrannosaurids, Gorgosaurus was a large bipedal predator, measuring in length and in body mass.
ProbrachylophosaurusProbrachylophosaurus bergei is a species of large herbivorous brachylophosaurin hadrosaurid dinosaur known from the Late Cretaceous Campanian Judith River Formation, of Montana and the Foremost Formation of Alberta. The significance of this particular hadrosaur taxon is that it is a transitional species between the genera Acristavus and Brachylophosaurus evolving from a crestless ancestor (the former genus) to its crested descendant (the latter genus) while changing the morphology of its nasal bones.
