In 2017, while browsing the fossil collections of the Yale Museum of Natural History, Peabody, University of Texas at Austin graduate student Simon Scarpetta came across a small lizard skull just under an inch long. The skull is perfectly preserved and, as it turned out, has not been studied by anyone. After research published in the journal Scientific Reports, it turned out that this fossil belongs to a new and previously unknown extinct species.
The 52 million-year-old skull has been stored in a specimen box at the Wyoming Museum since 1971.
“Lizards are small and their remains are prone to decay. Scientists mostly get fragmented bones, ”explains Simon Scarpetta, who is studying paleontology at the Jackson School of Earth Sciences at the University of Texas at Austin.
Scarpetta decided to take the skull to Jackson’s school for closer examination. A study was later published in which the remains were described as a new species of lizard, which Scarpetta named Kopidosaurus perplexus.
To study the lizard’s skull, Scarpetta created a digital scan of the fossil at the Jackson School’s high-resolution CT lab. Although some details helped identify the lizard as a new species, other characteristics of the skull overlapped with those of a number of different evolutionary groups.
All these groups belonged to the iguania suborder. It includes a number of different species of chameleons and iguanas. To better understand where the new species might fit into the suborder, Scarpetta compared the skull data with the phylogenetic tree of the iguania. For these purposes, he used data from other researchers collected on the basis of the DNA of living reptiles.
It turned out that the previously unknown fossil found belongs to several branches of the evolutionary tree.