How Was Dilophosaurus Discovered?

Dilophosaurus (Wikimedia Commons).

Of the dozen or so dinosaurs that every kid knows by heart, Dilophosaurus occupies the strangest position. This theropod's popularity can be attributed almost entirely to its colorful cameo in the first Jurassic Park movie, but almost all the details presented in that blockbuster were completely made up--including Dilophosaurus' petite size, prominent neck frill, and (most egregiously of all) its presumed ability to spit poison.

One way to bring Dilophosaurus down to earth is to describe the fairly unremarkable details of its discovery. In 1942, a young paleontologist named Sam Welles went on a fossil-hunting expedition to the Navajo country, a sparsely populated portion of the southwest U.S. that includes much of Arizona. Welles, who later become a professor at the prestigious University of California Museum of Paleontology, offers his eyewitness account on a taped UCMP Dilophosaurus tour:

"[A colleague] asked me to look up the report of a skeleton found in the Kayenta Formation, which might possibly be dinosaurian. I tried to find this and failed...and got hold of Jesse Williams, a Navajo who had discovered these bones in 1940. There were three dinosaurs in a triangle about twenty feet apart, and one was almost worthless, having been completely eroded. The second was a good skeleton showing everything except the front part of the skull.

The third gave us the front part of the skull and much of the front part of the skeleton. These we collected in a ten-day rush job, loaded them into the car, and brought them back to Berkeley."

Introducing Dilophosaurus - By Way of Megalosaurus

The above account is pretty straightforward, but the next installment of the Dilophosaurus saga is fairly twisty.

It took over a dozen years for Welles' bones to be cleaned and mounted, and it was only in 1954 that the "type specimen" was given the name Megalosaurus wetherelli. This must have been hugely anticlimactic to its discoverer, since Megalosaurus had been a "wastebasket taxon" for over a hundred years, comprising a huge number of poorly understood theropod "species" (many of which later turned out to deserve their own genus).

Determined to give his dinosaur a more secure identity, Welles returned to Navajo territory in 1964. This time he unearthed a fossil bearing a characteristic double crest on its skull, which was all the evidence he needed to erect a new genus and species, Dilophosaurus wetherelli. (In real time, this happened fairly slowly; it was only in 1970, six years after this latter expedition, that Welles felt he had made a solid enough case for his "two-crested lizard.")

There is a second named species of Dilophosaurus, D. sinensis, to which a Chinese paleontologist assigned a theropod fossil discovered in Yunnan province in 1987. Some experts believe that this may actually be a specimen of Cryolophosaurus, the "cold-crested lizard" (and close relative of Dilophosaurus) that was discovered in Antarctica in the early 1990's.

Before he died, Welles designated a third species of Dilophosaurus, D. breedorum, but never got around to publishing it.

Dilophosaurus - The Facts and the Fantasy

What, exactly, set Dilophosaurus apart from other theropod dinosaurs of early Jurassic North America (and possibly Asia)? Aside from the distinctive crest on its head, not much--this was your average, voracious, 1,000 to 2,000-pound meat eater, certainly no match for the likes of Allosaurus or Tyrannosaurus Rex. It's unclear why Jurassic Park author Michael Crichton even seized on Dilophosaurus in the first place, or why he chose to endow this dinosaur with its mythical features. (Not only did Dilophosaurus not spit poison, but, to date, paleontologists have yet to conclusively identify any genus of dinosaur that did!)

The details we do know about Dilophosaurus probably wouldn't make for a very good movie.

For example, one specimen of D. wetherelli has an abscess on its humerus (arm bone), most likely the result of a disease process, and another specimen has a weirdly foreshortened left humerus, which may have been a birth defect or a reaction to environmental conditions 190 million years ago. Limping, groaning, feverish theropods don't exactly make for big box office, which may partly excuse Michael Crichton's (and Steven Spielberg's) flights of fancy!

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Strauss, Bob. "How Was Dilophosaurus Discovered?" ThoughtCo, Mar. 3, 2017, Strauss, Bob. (2017, March 3). How Was Dilophosaurus Discovered? Retrieved from Strauss, Bob. "How Was Dilophosaurus Discovered?" ThoughtCo. (accessed November 21, 2017).