Tyrannosaurus of its time: Ancient super-predator was a thunderstorm of the entire Earth 300 million years ago

(ORDO NEWS) — The fanged member of the genus Whatcheeria reached 2 meters in length, and more than 300 million years ago was the main predator in sinkholes that turned into lakes of the American Midwest.

The Predator, an early four-legged vertebrate known as a tetrapod, lived about 328 million years ago during the early Carboniferous period.

This predator got its name – Whatcheeria deltae – in honor of the city of Watcher, Iowa, where many of its fossils were found.

He lived at a time when the region was covered in lush vegetation and dotted with sinkholes that later turned into lakes.

W. deltae may have lurked in these lakes, growing up to 2 meters long and looking like something like a big-toothed salamander.

Apex predator of the carboniferous

University of Chicago doctoral student Ben Otoo studied the Field Museum’s collection of 375 W. deltae specimens – some bone fragments and some near-complete skeletons – and noticed that the animal’s limb bones varied in size.

The differences in size were not based on when or where the fossils were found, so Otoo realized that he was looking at animal bones of different ages.

The smaller bones of the limbs had a length of about 10 centimeters, and the largest – 0.8 m.

This meant that Otoo and their colleagues had the opportunity to study how W. deltae grew . Early tetrapods, such as Whatcheeria, were related to modern reptiles, amphibians, and mammals, but were in a different evolutionary line from the ancestors of these three groups.

Modern birds and mammals tend to grow rapidly when young and then stop growing, while reptiles tend to grow rapidly at first and then continue to grow but more slowly.

Meanwhile, some amphibians grow slowly and steadily throughout their lives. Little was known about the size to which early tetrapods could grow.

By studying the growth rings in the bones, the scientists found that W. deltae grew very quickly at first, and then its growth rates slowed down, but remained constant.

All nine specimens they studied were adult juveniles and young adults, Otoo said.

Based on this data, paleontologists hypothesized that the animals grew to about 1 meter in length as they approached sexual maturity, and then grew more slowly in later adulthood.

This pattern in such an early tetrapod was surprising to scientists – they expected that rapid early growth would be associated with a terrestrial lifestyle and limited to mammals, birds and reptiles with faster metabolisms than early tetrapods.

But Whatcheeria was a surprise – and further study of this species may provide even more important information about the evolution of animals.


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