A reconstruction of the flesh-eating Concavenator corcovatus that lived 125 million years ago. Credit: Raul Martin

Sept. 8: A new dinosaur that lived about 125 million years ago and was previously unknown to science has got the name: the hunchback hunter of Cuenca.

Spanish paleontologists today announced their discovery of the fossil of a six-metre long flesh-eating dinosaur with a hump-like structure on its back never observed in dinosaurs before.

The well-preserved fossil, found embedded in a block of limestone at Las Hoyas near Cuenca in central Spain, was one of the great predators of its time and had structures on its skin that could have been forerunners to feathers in modern birds, the researchers said. Their paper on the new dinosaur will appear in the journal Nature on Thursday.

The fossil’s last two vertebrae in front of the pelvis project their neural spines on the back of the animal forming a hump whose function remains unknown, said Francisco Ortega, a biologist-paleontologist and the lead author of the paper. “This is one of its unique characteristics unknown in dinosaurs,” he said.

“The most plausible role for this structure is that of deposit of fat as is observed in some modern mammals such as the zebu, or humped cattle,” Ortega told The Telegraph. “But there are differences between the humps of mammals and the structure on this dinosaur. Mammals, for example, do not have internal bony support.”

However, he said, a structure as striking as this could play a role in communication between individuals or the same species, or be involved in supporting a fold of skin that assists in temperature regulation strategies.

The dinosaur named Concavenator corcovatus — to mean the hunchback hunter from Cuenca — has also thrown up another surprise. In many modern birds, the back edge of one of the bones of the forearm — the ulna — has a number of small bumps that serve as a zone for the insertion of the larger feathers of the wings.

(From left) Fernando Escaso, Francisco Ortega and Jose Sanz analyse the fossil of the new dinosaur named the hunchback hunter of Cuenca. Credit: Franciso Ortega

This feature has been previously recognised in small dinosaurs, closely related to birds, such as the velociraptors. “Surprisingly, Concavenator, which is four times larger than velociraptor, and too primitive to have feathers also has these small bumps,” Ortega said. “These structures represent an ancestral stage of the feathers of birds.”

A senior Indian paleontologist who was not associated with the finding said the hump as well as the skin structures could have been used for heat regulation. “Dinosaurs were cold-blooded — we know that similar anatomical features were used by other animals to absorb or prevent loss of heat,” said Ashok Sahni at the University of Lucknow.

Ortega and his colleagues Fernando Escaso and Jose Sanz had discovered the fossil in 2003 and have spent the past seven years processing in and analysing its anatomy in detail.

Sahni said the find of a new dinosaur in the 21st century isn’t surprising. “There are about 350 or 400 dinosaurs known, but there are vast tracts on Earth that remain unexplored where fossils remain unidentified,” Sahni told The Telegraph. “The Middle-East has some dinosaurs that have not been described yet.”

“The location and concentration of paleontologists,” he said, “determines where and which dinosaurs will be assigned new names.”