Just buried and compressed in different ways:
A new analysis of dinosaur fossils by University of Pennsylvania researchers has revealed that a number of specimens of the genus Psittacosaurus — once believed to represent three different species — are all members of a single species. The differences among the fossil remains that led other scientists to label them as separate species in fact arose from how the animals were buried and compressed, the study found.
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Based on the “old-fashioned” method of examining the physical skulls, the researchers concluded that the three purported species were in fact one. They propose that all three can be considered members of the species P. lujiatunensis.
Results from the geometric morphometric analysis, though not sufficient on its own to classify species, supported this conclusion and suggested that how an animal’s body was crushed as it fossilized — from the top, from the side or twisted — could lead to inaccurate species determinations.
“Our study found all of these false ‘species’ that are not biological species but are apparent species caused by the process of fossilization,” Dodson said.
The Penn team said their investigation shows the value of traditional taxonomic analysis, while also revealing the potential of a new approach to analyzing fossils.
The findings also illustrate the risks of large, general conclusions from a few apparently randomly preserved fossils.