Scientists have discovered a new "short-crested lizard" dinosaur species in Montana, and the findings could represent the transition between a non-crested ancestor like Acristavus and the large crests seen in adult Brachylophosaurus. The dinosaur had a small triangular bony crest extending from its skull.
The newly-discovered species, dubbed Probrachylophosaurus berge, was a hadrosaurine dinosaur that walked the Earth around what is now the Judith River formation about 79.5 million years ago, the Public Library of Sciences reported.
"This part of the Judith River Formation represents a slice of time intermediate between areas where lots of dinosaur fossils have been collected in the past. The new species that we find here are 'missing links' between known dinosaur species, so it's a really exciting field area," said Elizabeth Freedman Fowler of Montana State University.
Probrachylophosaurus' bony triangular nasal crest is somewhere in between what is seen in Acristavus and Brachylophosaurus. The fascinating feature may represent a transition between a transitional nasal shape of non-crested ancestors and large flat posteriorly oriented nasal crest of later species. The findings make sense because Probrachylophosaurus is believed to have lived between the times of Acristavus and Brachylophosaurus, making it an excellent candidate for an intermediate evolutionary link.
"In the early years of dinosaur paleontology, specimens were collected as isolated points, each so morphologically unique that their evolutionary relationships were difficult to determine. As more fossil specimens are collected, the gaps in morphology that previously separated species are being filled," the researchers wrote in the study.
The findings were published in a recent edition of the journal PLOS One.
