Historic ‘terror birds’ could have been no match for hungry big caimans

About 13 million years in the past in an unlimited South American wetland, colossal predators clashed. The fossilised bone from an unlimited flightless chicken present in Colombia exhibits tooth marks made by a large caiman.

Andrés Link on the University of the Andes in Colombia and his colleagues have been learning crocodile fossils in a museum assortment once they realised one of many bones didn’t match. It turned out to belong to a phorusrhacid chicken – a gaggle also called the “terror birds”. These high predators had hatchet-shaped beaks and highly effective legs with sharp claws on their toes. The fossilised bone got here from the decrease leg of a 2.5-metre-tall species, probably one of many largest forms of terror chicken but found.

But this predator could have met a grisly finish. The bone, initially found in Colombia’s Tatacoa desert area by native palaeontologist César Perdomo, was scarred with 4 deep divots: enamel marks.

Link and his workforce wished to know what beast dared wrap its jaws round such an intimidating predator. So they scanned the floor of the fossil to generate a digital mannequin of the tooth marks and in contrast them with the enamel of historical predators from the area. The perpetrator possible wasn’t a mammal.

“There’s no evidence of gnawing and the marks are rounded and in [a] line, more similar to those inflicted by crocodiles and caimans,” says Link.

The terror chicken lived at a time when northern South America was dominated by the Pebas system, a large community of wetlands interspersed with tropical forests and grasslands. The flooded ecosystem hosted an ideal variety of crocodilians, and the workforce discovered a match for the enamel marks in considered one of them: a large caiman referred to as Purussaurus neivensis. Link estimates the reptile would have been about 4.5 metres lengthy.

“Terror birds were undoubtedly at the top of the food chain,” says Link. “But this evidence shows us that they could also fall as prey of large caimans when approaching large water bodies. Maybe they went there to look for prey or [were] moving across this complex ecosystem.”

The workforce notes they’ll’t rule out the likelihood the chicken was already useless when the caiman discovered it, and the tooth marks are proof of scavenging. There are not any indicators of bone therapeutic across the tooth marks. So both manner, the chicken didn’t survive the encounter.

“These kinds of [tooth] traces are more common than people think,” says Carolina Acosta Hospitaleche on the National University of La Plata in Argentina.

In a examine revealed final 12 months, she and a colleague described tooth marks on a a lot smaller and older terror chicken fossil – roughly 43 million years outdated – from Argentina. The markings recommend an historical carnivorous marsupial consumed that chicken. Since these traces have been additionally on the decrease leg, Hospitaleche wonders if that a part of the fear chicken physique was a weak place for predators to chomp and grip their prey.

“[Bite marks] provide us with these amazing little snapshots into life in the past,” says Stephanie Drumheller on the University of Tennessee.

When learning historical environments, there’s a tendency to aim to exactly categorise extinct organisms inside explicit ecological roles, she says. However, meals webs will be complicated.

“This is an animal that was living in the water and doing things in the water, this is an animal that was living up on land and doing things upon land, and never the two shall meet,” says Drumheller. “But of course, nature is always messier than our nice, little, neat boxes.”