For fans of Jurassic Park, much of our understanding of dinosaurs is unfortunately built upon wild guesses as to how these prehistoric animals looked, moved and functioned (it’s not been tested yet, but I highly doubt velociraptors were proficient with door handles). A new study, published in Journal of Paleontology, has revealed that the dramatic scene in which Dennis Nedry comes to his grisly demise in the presence of a Dilophosaurus was somewhat inaccurate. As it turns out, these dinosaurs were less reptilian and actually more reflected the morphology of birds.
Dilophosaurus was actually the largest land animal of its time, stretching to 6 meters (20 feet) in length. Living around 183 million years ago during the Early Jurassic, this once-thought befrilled dinosaur was actually little known to palaeontologists, who had no idea how the animal looked or behaved. Despite this gap in the fossil record, it didn’t stop Steven Spielberg from imagining an unusual creature who sported delicate frilled headwear and sprayed tarry venom.
In a statement, lead author Adam Marsh called it "pretty much the best, worst-known dinosaur. Until this study, nobody knew what Dilophosaurus looked like or how it evolved."
To try and understand these majorly misunderstood animals, Marsh carried out analyses of the five most complete Dilophosaurus specimens, including two previously unstudied specimens. One of the older preserved specimens was the standard for all theories on the life and size of Dilophosaurus, which was recreated using plaster, but the 1954 paper describing it is a little vague, to put it lightly, and the end result made it very difficult to glean much from this poorly recreated fossil record.
Early descriptions formed an image of a creature with a weak jaw and fragile crest framing its face, something Marsh thinks might have influenced the novel and film's idea it spat venom. But further investigation showed the jawbones actually acted as scaffolding for powerful muscles surrounding the face. A far throw from the light-weight frills seen in Jurassic Park. The findings also revealed that Dilophosaurus’s bones were pneumatic, meaning they were mottled with air pockets. This gives the animal a very light skeletal system, which is a characteristic of many extant birds.
These pneumatic bones help birds inflate stretchy skin for mating displays and even helps them cool down by releasing booming sounds that are facilitated by their air-laden bones’ acoustics. The unique structure of Dilophosaurus' sinus cavity seems to indicate that it could perform similar feats with its headgear, according to Marsh’s investigations.
The specimens inspected were all found in Arizona and belong to the Navajo, two of which are kept at the Jackson School Museum of Earth History where Matthew Brown, director of the Vertebrate Paleontology Collections, looks after them. "One of the most important responsibilities of our museum is curation," said Brown in a statement. "We are very excited to help share these iconic Navajo Nation fossils with the world through research and educational outreach, as well as preserve them for future generations."