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A newly discovered dinosaur may have been a flightless roadrunner which has prompted a rethink of the evolution of birds, scientists have found.
The “bizarre” fossil found in China has helped fill a 30-million-year “gap” in the evolutionary history of birds.
Chinese scientists say the previously unknown species was a “high-speed runner” which lived in a “swamp-like” environment.
Present day birds descended from theropod dinosaurs by the Late Jurassic period.
But the exact process has remained a mystery due to a lack of fossils from the Jurassic to the oldest known record of Cretaceous birds around 150 million years ago.
Now a Chinese team has described a new 150-million-year-old avialan theropod found in Zhenghe County in Fujian Province.
They said the new species, named Fujianvenator prodigiosus, exhibits a strange mixture of features shared with other predecessors of today’s birds.
Dr Wang Min, of the Chinese Academy of Sciences in Beijing, said: “Our comparative analyses show that marked changes in body plan occurred along the early avialan line, which is largely driven by the forelimb, eventually giving rise to the typical bird limb proportion.
“However, Fujianvenator is an odd species that diverged from this main trajectory and evolved bizarre hindlimb architecture.”
He said the surprisingly elongate lower leg and other features suggest that Fujianvenator lived in a “swamp-like” environment and was a quick runner or a long-legged wader, representing a previously unknown version of early birds.
Study lead author Dr Xu Liming, of the Fujian Institute of Geological Survey (FIGS), said: “Besides Fujianvenator, we have found abundant other vertebrates, including teleosts, testudines and choristoderes.”
The researchers say that during the Late Jurassic-Early Cretaceous period, south eastern China underwent intensive tectonic activities, resulting in the unusual landscape where Fujianvenator was found.
Study co-author Dr. Zhou Zhonghe added: “The extraordinary diversity, unique vertebrate composition, and paleoenvironment strongly indicate that this locality documents a terrestrial fauna, which we named the Zhenghe Fauna.”
The team say their findings, published in the journal Science, opens a “new window” into the Late Jurassic terrestrial ecosystem of the planet, and they plan to continue their exploration of Zhenghe and nearby areas.