The team from University College London (UCL) and Stony Brook University, New York, said the frog would have had a body length of about 40cm (16 inches), and was among the largest of its kind to be found.

"This frog, a relative of today's horned toads, would have been the size of a slightly squashed beach-ball, with short legs and a big mouth," explained co-author Susan Evans, from UCL's Department of Cell and Developmental Biology.

"If it shared the aggressive temperament and 'sit-and-wait' ambush tactics of [present-day] horned toads, it would have been a formidable predator on small animals.

"Its diet would most likely have consisted of insects and small vertebrates like lizards, but it's not impossible that Beelzebufo might even have munched on hatchling or juvenile dinosaurs."