Perhaps Birgeria americana was a top predator of the Early Triassic

Birgeria americana fossil (Image courtesy UZH)
Birgeria americana fossil (Image courtesy UZH)

An article published in the “Journal of Paleontology” describes the discovery of what might have been a top predator at the beginning of the Triassic period, between 252 and 247 million years ago. Named Birgeria americana, this fish was long probably less than 2 meters (about 6′) but after the great extinction of the end of the Permian it was perhaps at the apex of the food chain in its ecosystem.

The mass extinction that took place around 252 million years ago was the worst in the history of life on Earth, with the disappearance of about 90% of marine species. Until a few years ago, paleontologists thought that the first top predators, those at the top of their food chain, appeared only in the Middle Triassic, between 247 and 235 million years ago, but already in March 2014 the results of a research suggested that large predators appeared in the oceans shortly after the great extinction.

A new confirmation of this theory comes from the discovery of a partial skull of a fish dating back to the Early Triassic period. Fish belonging to the Birgeria genus have long been known in various species. However, according to a team of Swiss and American researchers led by the Paleontological Institute and Museum of the University of Zurich, Switzerland, the new fossils belong to a species other than the known ones that lived in today’s Nevada.

The skull attributed to a species called Birgeria americana has a length of 26 centimeters and has characteristics that reveal its nature as a predator. It was equipped with three parallel rows of sharp teeth long up to 2 centimeters along the edges of its jaws and other smaller teeth inside its mouth. According to the researchers, it hunted in a manner similar to the great white shark, chasing its prey, biting it, and finally swallowing it whole.

Such an animal could be a top predator in its ecosystem. This is a further confirmation that shortly after the mass extinction of the end of the Permian new top predators emerged. Fish of the Birgeria genus were of the bony fish type and Birgeria americana lived in an area that at that time was close to the equator, an indication that the sea temperature didn’t exceed 36° Celsius. That’s because today’s bony fish eggs don’t develop normally at temperatures exceeding 36° Celsius.

This discovery further confirms that the food chain reformed more quickly than expected after the extinction at the end of the Permian. Previously paleontologists thought that the regions that were then at the equator could be too hot for vertebrates. Instead, not only there were some but already at the beginning of the Triassic maybe in that area there was a superpredator.

Birgeria americana  reconstruction (Image courtesy Nadine Bösch)
Birgeria americana reconstruction (Image courtesy Nadine Bösch)

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