Gargoyleosaurus

Phylogeny: Dinosauria > Ornithischia > Genasauria > Thyreophora > Thyreophoroidea > Eurypoda > Ankylosauria > Euankylosauria > Nodosauridae (?)

Overview: With a modest understanding of dinosaurs, one might be tempted to see the stegosaurs (Stegosaurus, Kentrosaurus, etc.) as a strictly Jurassic group of herbivores and the Ankylosaurs (Ankylosaurus, Euoplocephalus, etc.) as a Cretaceous lineage. In reality, there is a fair bit of temporal overlap. The former would persist for a while into the Early Cretaceous, while the ankylosaurs actually first appear in the fossil record during the Middle to Late Jurassic. Taxa in both groups occasionally coexisted. Gargoyleosaurus is a good example of this. Fossils of the animal are known from the famous Morrison Formation of North America, which also contains the remains of the famous Stegosaurus. The two dinosaurs shared the same environment, likely having different ecological roles or niches. Gargoyleosaurus probably fed entirely on low-level plant life.

While the stegosaurs usually had upward-standing plates along their backs and spiked tails, the armor on ankylosaurs like Gargoyleosaurus was quite different. This dinosaur had rows of bony scutes running along its back, sides, tail and neck. It was well protected from all but the largest of theropods. Unfortunately for Gargoyleosaurus, it lived among a variety of large theropods, namely taxa like Ceratosaurus, Torvosaurus and Allosaurus. Gargoyleosaurus lacked a club on the end of its tail, which could imply it was a nodosaurid ankylosaur – ankylosaurids usually had such clubs. However, it could’ve been an early member of the Ankylosauridae, as we can assume the most basal of them didn’t have such a trait, which fossil evidence does support. Gargoyleosaurus was formally named as a genus in 1998, its generic name referring to the gargoyle like appearance of its holotype fossil.