Giant dinosaur-eating frog species identified

Melbourne: A large, now extinct, frog species that lived about 68 million years ago in Madagascar would have been capable of eating small dinosaurs, a study suggests.

Researchers studied the bite force of South American horned frogs from the living genus Ceratophrys, known as Pacman frogs for their characteristic round shape and large mouth, similar to the video game character Pac-Man.

Scientists, including those from University of Adelaide in Australia, found that living large South American horned frogs have similar bite forces to those of mammalian predators.

“Unlike the vast majority of frogs which have weak jaws and typically consume small prey, horned frogs ambush animals as large as themselves, including other frogs, snakes, and rodents,” said Marc Jones, researcher at the University of Adelaide.

“And their powerful jaws play a critical role in grabbing and subduing the prey,” said Jones.

The study found that small horned frogs, with head width of about 4.5 centimetre (cm), can bite with a force of 30 newtons (N) or about three kilogrammes (kg).

A scaling experiment, comparing bite force with head and body size, calculated that large horned frogs that are found in the tropical and subtropical moist lowland forests of South America, with a head width of up to 10 cm, would have a bite force of almost 500 N.

This is comparable to reptiles and mammals with a similar head size, researchers said.

“This would feel like having 50 litres of water balanced on your fingertip,” said Kristopher Lappin, professor at California State Polytechnic University – Pomona in the US.

Based on their scaling relationship, the scientists estimated the bite force of the giant extinct frog Beelzebufo, which is in many ways similar to living horned frogs, may have had a bite up to 2200 N, comparable to formidable mammalian predators such as wolves and female tigers.

“At this bite force, Beelzebufo would have been capable of subduing the small and juvenile dinosaurs that shared its environment,” said Jones.

The scientists measured bite force using a custom-made force transducer, a device which accurately measures the force applied to two plates covered with leather when an animal bites them.

“This is the first time bite force has been measured in a frog,” said Lappin.

“The bite of a large Beelzebufo would have been remarkable, definitely not something I would want to experience firsthand,” Lappin said.

The study was published in the journal Scientific Reports.