KritosaurusKritosaurus is an incompletely known genus of hadrosaurid (duck-billed) dinosaur. It lived about 74.5-66 million years ago, in the Late Cretaceous of North America. The name means "separated lizard" (referring to the arrangement of the cheek bones in an incomplete type skull), but is often mistranslated as "noble lizard" in reference to the presumed "Roman nose" (in the original specimen, the nasal region was fragmented and disarticulated, and was originally restored flat).
KritosauriniKritosaurini is a tribe of saurolophine hadrosaurid dinosaurs from the Late Cretaceous. The first member of the group discovered and named was Kritosaurus; it was named by paleontologist Barnum Brown in 1910. Four years later, Canadian paleontologist Lawrence Lambe would name Gryposaurus. The similarity between the two taxa was immediately recognized, and throughout the twentieth century the validity of the latter genus was doubted, with it being suggested both species were the same.
TroodonTroodon (ˈtroʊ.ədɒn ; Troödon in older sources) is a former wastebasket taxon and a potentially dubious genus of relatively small, bird-like theropod dinosaurs definitively known from the Campanian age of the Late Cretaceous period (about 77 mya). It includes at least one species, Troodon formosus, known from Montana. Discovered in October 1855, T. formosus was among the first dinosaurs found in North America, although it was thought to be a lizard until 1877.
ParasaurolophusParasaurolophus (ˌpærəsɔːˈrɒləfəs,_-ˌsɔːrəˈloʊfəs; meaning "near crested lizard" in reference to Saurolophus) is a genus of hadrosaurid "duck-billed" dinosaur that lived in what is now western North America and possibly Asia during the Late Cretaceous period, about 76.5–73 million years ago. It was a herbivore that could move as both as a biped and as a quadruped. Three species are universally recognized: P. walkeri (the type species), P. tubicen, and the short-crested P. cyrtocristatus. Additionally, a fourth species, P.
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.
