Probrachylophosaurus

Probrachylophosaurus 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. In 1981 and 1994, Mark Goodwin of the University of California Museum of Paleontology excavated limb bones and a vertebra near Rudyard in the north of Montana, at a site originally discovered by Kyoko Kishi. After a school class found some more bones, in 2007 and 2008 a team of the Museum of the Rockies secured the remainder of a hadrosaur skeleton, among which the skull. The fossil was donated to the Museum of the Rockies by land owners Nolan and Cheryl Fladstol; and John and Claire Wendland. In 2009, 2010 and 2011, the find was reported in the scientific literature as a possible new species of Brachylophosaurus. In 2015, the type species Probrachylophosaurus bergei was named and described by Elizabeth A. Freedman Fowler and Jack Horner. The generic name is a combination of Latin pro, "before", and Brachylophosaurus and refers to the genus being situated in a lower position in the stratification than its relative Brachylophosaurus. The specific name honours Sam Berge, one of the landowners, and his friends who have supported the research. Probrachylophosaurus was one of eighteen dinosaur taxa from 2015 to be described in open access or free-to-read journals. The holotype, MOR 2919, was found in a layer of the Judith River Formation dating from the Campanian and being between 79.8 and 79.5 million years old, plus or minus two hundred thousand years. It consists of a partial skeleton with skull, of an adult individual.