A new study by scientists from the University of Bath and the University of Chicago points to the second option. The creatures were named Nanotyrannus lancensis.

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Despite their name, Nanotyrannosaurs were not as small as they looked. Be obliged to 5 meters long and weighing up to 1,500 kilogramsThey grew to only 15% the size of an adult tyrannosaurus. And although, as for the sizes of most modern animals, this is a lot, next to their larger “brothers” they really looked like babies.

After numerous studies, nearly 150 differences were found in the skeletons of these two species, which made it possible to reveal the main difference between them. Nanotyrannosaurs had long, sturdy, functional forelimbs rather than vestigial appendages like large tyrannosaurs.

During the study of annual markings on bones, scientists determined the average age of nanotyrannosaurs to be 13-15 years, which corresponds to the age of young tyrannosaurs. However, the marks are placed so close together that the difference in bone growth between years is symbolic. the creature’s approach to its maximum size indicates its maturation. Young tyrannosaurs grew rapidly and added hundreds of kilograms of weight per year, but in this case the picture is completely different.

Finally, no transitional “juvenile” form has been found that combines the characteristics of the two species and shows the difference between them. A direct comparison of the skulls of a juvenile tyrannosaurus and a nanotyrannosaurus showed how different they were. The first was to be a strong and clumsy hunter, the second was already a mobile and agile hunter.

Comparison of Tyrannosaurus and Nanotyrannosaurus / Photo: University of Bath

The research is far from complete; Scientists do not ignore new discoveries.