Fort Lauderdale, Florida

Missing link: the ‘Archaeoraptor’ fossil is a composite, not a new species. Credit: REX DALTON

It could have been an important clue to dinosaur and bird evolution. But a panel of palaeontologists last week confirmed that a fossil of a toothed bird — originally thought to be an important new species — is a composite of a least two separate specimens.

The fossil, which is thought to have been smuggled out of China, was bought early last year by amateur collectors, who paid $80,000 for it at an Arizona mineral show (see Nature 403, 689 ; 2000). It will be returned to China in June as a result of negotiations completed last week while the fossil was being analysed at the US National Museum of Natural History in Washington DC.

According to several palaeontologists, the specimen still might have implications for the evolution of birds, and scientists at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing are keen to study it.

But “it took about five minutes” to determine that the fossil was a composite, says Mark Norell, chairman of vertebrate palaeontology at the American Museum of Natural History in New York, and a member of the five-scientist panel.

According to Norell, the fossil tail of a primate bird had been inserted into the slab with the fossil remains of a more advanced bird, creating the appearance of a unknown specimen. Such fossils are typically altered in China to boost their value on the global underground market — they are classed as ‘national treasures’ in China, and cannot be sold legally.

The fossil — never named scientifically in a peer-reviewed journal, but known as ‘Archaeoraptor’ — was included in an article on bird evolution in National Geographic last November. The magazine had expected a paper on the specimen to appear in a scientific journal before its own article was published. But both Nature and Science declined to publish a submitted manuscript on the fossil.

National Geographic funded last week's analysis of the specimen, flying in a Chinese scientist and paying $5,000 for the facing, counter-slab of parts of the ‘Archaeoraptor’ specimen. This counter-slab definitively proved the fossil's composite nature.

Archaeoraptor’ was discussed last week at the first Florida Symposium on Dinosaur Bird Evolution in Fort Lauderdale, sponsored by the Graves Museum of Archaeology and Natural History. But a lecture on the fossil by Stephen Czerkas, the amateur collector who first purchased it, threw little light on the controversy surrounding the specimen.

Indeed Czerkas, who directs a small museum in Blanding, Utah, also displayed and gave a talk on a second bird fossil. Several academic palaeontologists suggested this might also come from China, raising questions about whether the specimen had been smuggled out before Czerkas obtained it.

During two talks, Czerkas did not explain the origins of either specimen, or describe any scientific exchange with Chinese institutes. But he did publicly acknowledge for the first time that ‘Archaeoraptor’ was a composite.

Referring to the new fossil as “an arboreal theropod” with “remarkable implications”, Czerkas claimed that it “represents a previously unknown lineage of dinosaurs that could climb”.

But Kevin Padian, a curator at the University of California's Museum of Paleontology, said: “The idea that you look at a couple of features and say it lived in a tree is just not science. Such a determination requires a detailed study of all joints and motions.” Czerkas refused to be interviewed after his talks.

The new specimen prompted Padian to call for aggressive new efforts by scientists and authorities to address the illicit trade in fossils. An international protocol is needed to keep the specimens in China “where they belong”, he said.