Lizard Royalty

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The iconic Tyrannosaurus rex was not the only “royalty” that dominated the prehistoric world millions of years ago, USA Today reported.

The T-rex – which stands for “tyrant lizard king” – was actually two species: The T. imperator, or “tyrant lizard emperor,” and the T. regina, or the “tyrant lizard queen,” a new research paper said.

Lead author Gregory Paul and his team studied the remains of 37 different Tyrannosauruses and noticed a variety of strengths in the dinos’ femurs. They also found that some remains had thin femurs with only one incisor tooth.

The researchers also analyzed the layers of sediment that held each fossil and discovered that the Tyrannosauruses with more robust femurs and two incisors appeared in deeper layers – meaning they were older species.

Newer sediment, meanwhile, revealed different variations of the extinct creatures.

Their findings concluded that the Tyrannosauruses began with the T. imperator, which evolved millions of years later into T. rex and T. regina.

The precursor T. imperator sported two incisors and strong femurs. His successor, the T. rex, was equipped with strong femurs, but only one incisor tooth. As for the “queen,” it had thinner bones and one incisor tooth.

The study could potentially revamp the nomenclature of currently discovered Tyrannosauruses, including those displayed in museums.

However, many paleontologists and museum curators remained skeptical about the results, adding that there was not enough evidence to suggest the existence of lizard royalty.

“The diagnoses provided for each species are incredibly vague,” said Jingmai O’Connor of Chicago’s Fields Museum, where the popular T. rex, Sue, is displayed.