If you could invent a time machine and hop back 140 million years, to the earliest part of the Cretaceous Period, you would likely see at least one basal iguanodontidian or “iguanodontid.” These ornithischian dinosaurs (the group including ankylosaurs, stegosaurs, horned dinosaurs, and duck-billed dinosaurs) lived all around the globe. The basal iguanodontidians were those at the bottom of the iguanodontid family tree, the very earliest members of a group that would one day include Iguanodon and hadrosaurs such as Parasaurolophus.
Although iguanodontid body fossils have been found in abundance in the United States, there has been no evidence of these dinosaurs in Alberta—until now.
The Royal Tyrrell Museum’s Curator of Dinosaurs, Dr. Donald Henderson, published a paper in Cretaceous Research on a fossil footprint likely left by an iguanodontid. The specimen was found exposed on the underside of a sandstone ledge in southwestern Alberta and is preserved as a natural cast.
There are several reasons that Henderson believes this footprint belongs to an iguanodontid:
This is an exciting discovery because it fills in an obvious gap in Alberta’s fossil record. Given its richness and that basal iguanodontids are found around the world, it is somewhat surprising that evidence of them has not been found in Alberta before. Henderson suggests that it may be because these older rock layers are found in areas which are in relatively inaccessible remote locations, with heavy forests, and often deeply buried under younger rocks. In contrast, better known species, such as the hadrosaur Corythosaurus, from the Late Cretaceous (~100.5 – 66 million years ago) are found in wide open, prairie areas where fossils rapidly erode out of the ground. The discovery of this iguanodontid footprint proves that these dinosaurs lived in Alberta and provides hope that someday more of their fossils will be discovered.
The article, “The first evidence of iguanodontids (Dinosauria: Ornithischia) in Alberta, Canada: A fossil footprint from the Early Cretaceous” was published April 25, 2017 in Cretaceous Research.