Dr. Donald Henderson finds first evidence of iguanodontids in Alberta

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.

Iguanodon

An Iguanodon.

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.

image description

The trackway in situ

There are several reasons that Henderson believes this footprint belongs to an iguanodontid:

Iguanodont footprint

Measurements of the track

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.

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3 thoughts on “Dr. Donald Henderson finds first evidence of iguanodontids in Alberta

  1. Not a lot of physical similarities but can I assume that today’s iguanas count these fellas as their great-grand-ancestors? Or did they arise from a different line?

    • Thank you for your question. Despite the name, iguanas and iguanodontids are not particularly closely related (except in the sense that all vertebrates are related). The name “Iguanodon” means “iguana tooth”, and refers to the similarity between the teeth of these two herbivorous reptiles (although iguanodontid teeth were much bigger!). The only living animals that are descended from dinosaurs are birds. Iguanas arose from a very different line.

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