For 150 years the famous winged fossil Archeopteryx has enjoyed being called the world's oldest bird, until a chicken- sized dinosaur fossil found in China proved that the species is just another feathery dinosaur.

The discovery of the newly found fossil dubbed Xiaotingia zhengi is challenging the long-held belief that the Archeopteryx is the pre-cursor of the modern bird. A report from Professor Xing Xu, a paleontologist at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, detailed the anatomy of the Xiaotinghia zhengi as a two-pound creature with feathers, sharp claws, and a small shallow snout like Archeopteryx. It may have lived in northeastern China during the late Jurassic period as published in the scientific journal "Nature".

"There are many, many features that suggest that Xiaotingia and Archaeopteryx are a type of dinosaur called Deinonychosaurs rather than birds. For example, both have a large hole in front of the eye; this big hole is only seen in these species and is not present in any other birds.

"Archaeopteryx and Xiaotingia are very, very similar to other Deinonychosaurs in having a quite interesting feature - the whole group is categorised by a highly specialised second pedo-digit which is highly extensible, and both Archaeopteryx and Xiaotingia show initial development of this feature."

Scientists have long believed that Archeopteryx, discovered in Bavaria in 1861, was the missing link between dinosaur and bird evolution. The fossil which has both dinosaur and bird characteristics have been accepted as the original bird.

Recent discoveries of other fossils with three-fingered hands, wishbone and plumage have called into question Archaeopteryx's position as bird ancestor. In 2010, a study suggested that it has more similarities to velociraptors and that its heavy bones could have prevented it from flying.

Archeopteryx' supporters could still take comfort in the fact that the new fossil still hasn't swayed scientists against the feathered dinosaur.

"I'm not 100% convinced of the results. We need to be cautious about embracing this proposal," according to Luis Chiappe, director of the Dinosaur Institute at the National History Museum in Los Angeles. He added that Xiaotingia's remains are too broken down to form a conclusive report.

The fossil's exact origins are also impeding other scientists from jumping into the Archeopteryx isn't a bird side of the debate. The specimen was bought from a dealer who didn't know where it was found. Professor Xu however stands by his conclusion and denies the specimen is a forgery.