Tyrannosaurus Contains Two Separate Dinosaur Species Along 'Rex,' Theory Claims

The most popular dinosaur might have been branched out to three various species, a new study suggests. The prehistoric beast Tyrannosaurus rex, according to experts, should be joined by a completely separate species due to their similarities.

Alongside the Tyrannosaurus rex, the research implies that the Tyrannosaurus imperator (emperor tyrant lizard) and the Tyrannosaurus regina (tyrant lizard queen) should fall under the same species.

The proposal from the new study sparked a discussion among paleontologists. Many of the renowned groups in the community require additional proof, as they have been skeptical of the paper's result since its release.

Tyrannosaurus Rex Have Three Species

(Photo: Oli Scarff/Getty Images)
LONDON - MARCH 18: An adult Tyrannosaurs Rex robotic dinosaur performs in the O2 arena ahead of the forthcoming European leg of the live show 'Walking With Dinosaurs' on March 18, 2009, in London, England. The live arena show, toured throughout North America, tours the UK from July 2009. The £10 million show features 15 life-sized mechanical dinosaurs and is based upon the hit BBC TV series of the same name.

The paleontology community conducted several studies regarding the biological and evolutionary aspects surrounding the famous Tyrannosaurus rex. The dinosaur must have spread its species across the planet based on the study's findings.

The new theory was compiled due to the fact that numerous remains and other evidence of the beast were scattered in various regions of New Mexico, Western Canada, and North America. In addition, the species of Tyrannosaurus rex roamed in the prehistoric era for more than one million years.

The Tyrannosaurus rex's territory and its long period of existence add to the possibility that the species branched out and formed a new type of species. According to the authors, the dinosaur remains support their latest hypothesis, as there were excavated fossils that provide several differences from what we thought about the gigantic carnivore.

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T. Rex, T. Imperator, and T, Regina

The latest research on Tyrannosaurus rex's species was led by independent paleontology expert and prominent prehistory illustrator Gregory Paul.

The authors explained that the Tyrannosaurus fossils recovered in previous studies have major distinctions compared to other massive predatory beasts of the same clade.

Due to the scale of differences of the bones in just a single species of dinosaurs, the experts concluded that the Tyrannosaurus rex could be split into three separate clusters. Each of these subgroups is categorized based on the presence of their chisel-like teeth and stoutness of the skeleton itself.

The study observed 37 Tyrannosaurus rex fossils, gathering measurements including their lower jaw teeth and femurs. The majority of the fossil population was unearthed from Hell Creek Formation, located in North America's Upper Cretaceous site.

The researchers noted that three separate species could be established from the remains buried in the site's oldest layer, which have a strong set of bones, two pairs of chisel-like teeth (Tyrannosaurus imperator), and two other dinosaurs located in the more recent, upper rock layers. Both of the younger skeletons have a single pair of chisel-like teeth, with the first having an elongated and slim body (Tyrannosaurus regina) and the other with a robust body (Tyrannosaurus rex).

Other institutions challenged the study due to the lack of data regarding the discovery. In addition, there are details that might have been missed, causing the overall conclusion of the research to have discrepancies.

Further studies over a wider range of fossil populations are expected to confirm the theory on Tyrannosaurus rex. The study was published in the journal Evolutionary Biology, titled "The Tyrant Lizard King, Queen, and Emperor: Multiple Lines of Morphological and Stratigraphic Evidence Support Subtle Evolution and Probable Speciation Within the North American Genus Tyrannosaurus."