Three Parrot Dinosaur 'Species' Were Actually Just One

By using a cutting-edge laser system, paleontologists have refined their understanding of the "Parrot Dinosaur," a genus otherwise known as Psittacosaurus, concluding that three known "species" of the creature are actually all one in the same.

The discovery, the researchers from University of Pennsylvania hope, will forge a path for this new method of laser analysis to be used in other realms of paleontology.

Differences in the faux species that lead to their classification as unique species in the Psittacosaurus genus were due to the way the creatures' bones were crushed during the fossilization process and not because of any genealogical differences, the researchers contend.

"Our study found all of these false 'species' that are not biological species but are apparent species caused by the process of fossilization," said senior author Peter Dodson, professor of anatomy and paleontology at University of Pennsylvania.

The laser system the research team employed uses a technique known as "three-dimensional geometric morphometrics," which can provide extremely detailed data about the shape of different specimens.

According to the University of Pennsylvania, this study is the first time the technique has been used to study dinosaur fossils and "could lead to a re-examination of the taxonomic classifications of additional dinosaur species as well as other long-extinct fossil organisms."

Dodson and his colleagues analyzed fossilized remains that had originally been identified as one of three different species, P. lujiatunensis, P. major or Hongshanosaurus houi, the researchers stated. The fossils were discovered in the Lujiatun beds of northeastern China's Yixian Formation.

The researchers used two techniques to compare and contrast the specimens, the university wrote in a statement.

"First they conducted a traditional study in which they examined every skull that had been classified as one of those three species -- a total of 74 specimens -- for a variety of characteristics that had been used in prior studies to distinguish the species. The Penn team also compared these fossils to skulls that had been classified as belonging to eight other Psittacosaurus species.

"Next they completed a more high-tech analysis of 30 skulls from the three named species. Using a hand-held stylus that captures a point in space relative to a transmitter, they pinpointed 56 'landmarks,' or particular anatomical locations, on each fossil and compared the relative position of those marks between specimens. They also used a hand-held, laser-emitting scanner to make a three-dimensional image of each specimen, similar to a CT scan, from which they also collected landmark data."

What they found was enough to conclude that the three species were in fact more likely to be from just one: P. lujiatunensis.

Because the beak-faced Parrot Dinosaur, which roamed the Earth 125 million years ago, is one of the most abundant dinosaurs known to science, with more than 400 individual fossils collected so far, including many complete skeletons, the researchers felt it was a proper candidate for reexamination.

"For example, if you have a single dachshund and a single beagle, they may appear to be different species until you found 40 dachshund-beagle mixes of various grades to examine," said Brandon Hedrick, a doctoral student and study co-author.

As many as 11 species of the Psittacosaurus genus had previously been identified, but the researchers' laser analysis, coupled with "old fashioned" physical examination methods brings that number down a few notches.

"Hopefully this will open up the paleontological community to using three-dimensional geometrics morphometrics in a variety of ways," Hedrick said. "This technique has limitless applications to understanding dinosaurs."

The researchers work is scheduled for publication in the journal PLOS One.

See Also: 'Parrot Dinosaur' was a Quadruped at Birth and Grew to Walk on Two Legs, Study Finds