A dinosaur claw fossil found in Brazil reinforces the theory of an evolutionary link between dinosaurs and birds, a new study says. Brazilian scientists dubbed the dinosaur the dino-bird, which they said was found in Minas Gerais state, about 370 miles northwest of Rio.

A fossilized finger-nail from a Maniraptoran dinosaur, found in Uberaba, Minas Gerais, 560 miles from Rio, is shown by geologist Ismar de Souza Carvalho, at the Federal University of Rio de Janeiro (UFRJ), in Rio de Janeiro, Brazil, Thursday, May 18, 2006. Ismar de Souza Carvalho says the Maniraptoran dinosaur is a significant find because it proves the transition of dinosaurs into birds.[AP Photo]

Ismar de Souza Carvalho, who co-authored the study, said Thursday that it likely belonged to an unknown group of dinosaurs who walked the Earth some 70 million years ago.

"The anatomic structure of this claw shows, quite possibly, the link between carnivore dinosaurs and birds that exist today," said Carvalho, a member of the Paleontological Investigation Center at Minas Gerais state university.

One expert not involved in the study said that while the theory of a link between dinosaurs and birds has gained acceptance, he expressed doubt that a claw fragment could prove the existence of a previously unknown dinosaur.

"If this claw was all that was found, then it would be rather extravagant to create an elaborate theory based upon it. This claw doesn't add particularly much to our knowledge of the origins of birds, but it does show that raptor dinosaurs were present in Brazil toward the end of the age of dinosaurs," Thomas R. Holtz, Jr., a vertebrate paleontologist at the University of Maryland, said Friday.

"The claw is similar in shape to that of many other raptors, such as velociraptors. But from there we can't infer it is likely a similar dinosaur."

The Brazilian findings were published in the magazine of the Argentine Natural Science Museum.