New fossil lends weight to giant bird theories
Wed, Aug 10, 2011
A gigantic prehistoric bird which could have been as big as an ostrich has been identified from a single jawbone.
The new bird, estimated to have been between two and three metres tall, lived around 85 million years ago in Kazakhstan and lay unrecognised in a museum for years until being identified by palaeontologists. Named Samrukia nessovi, it represents one of the largest birds known from the Cretaceous period, a time when dinosaurs roamed the earth.
The fossil is only the second giant, land-living bird species to be discovered in Cretaceous-aged rocks and the first to be found in Asia. A previously recognised species, Gargantuavis philoinos, was named in 1998 from France but experts have argued over its identification. In a paper published today [10 August] in Biology Letters, scientists suggest that the new, Kazakh specimen confirms the presence of giant birds in the Cretaceous period.
Dr Darren Naish, from the University of Portsmouth, said that the creature provides significant new information on life in Cretaceous times.
He said: “Since the 1850s we’ve known that numerous bird species lived during the age of the dinosaurs (known as the Mesozoic Era), but virtually all were crow-sized or smaller. The ostrich-sized Gargantuavis from France is the one notable exception and now this new Mesozoic bird from Kazakhstan – known only from its toothless lower jaw – shows that gigantic birds also lived in Cretaceous Central Asia.
“We can now be really confident that Mesozoic terrestrial birds weren't all thrush-sized or crow-sized animals - giant size definitely evolved in these animals and giant forms were living in at least two distinct regions. This fits into a larger, emerging picture that Mesozoic birds were ecologically diverse, with lots of overlap between them and modern groups.
“The fragmentary nature of our Samrukia specimen will always mean that some people have doubts about it, but specialists who have seen the remains agree with our interpretation. The French Gargantuavis has already demonstrated the presence of giant Cretaceous birds and we argue that Samrukia adds a second example and increases the significance of Gargantuavis since it shows that it wasn't a one off.”
The skull of the new bird would have been about 30 cm long and if flightless it could have stood 2-3 metres tall. If it flew, its wingspan is likely to have exceeded 4 metres. Dr Naish, an Honorary Research Associate in the University’s School of Earth & Environmental Sciences, said that there is as yet no way to tell if the bird was flightless like an ostrich or whether it took to the skies.
He said: “Unfortunately we have only the lower jaw, and this doesn’t provide key information on what the whole bird was like. We hope that new material will be unearthed to provide us with more information, such as understanding what role it was playing in Cretaceous ecosystems.
“We do know that the fossil came from a floodplain environment. This would have been a large flattish plain, criss-crossed by big, meandering rivers. Fossil wood shows that forests were present nearby and aquatic animals indicate the continual presence of lakes, pools or big rivers. Samrukia was conceivably in danger from tyrannosaurs, dromaeosaurs and other predatory dinosaurs that occurred in the same region but we can't say whether Samrukia itself was predatory, herbivorous or omnivorous as the lower jaws don't reveal any obvious specialisations for, say, dedicated plant-eating or feeding on aquatic prey.
“People tend to forget that birds co-existed with their dinosaurian relatives but it now seems that the Cretaceous was not a ‘dinosaurs-only theme park.' This find confirms that large birds were living alongside dinosaurs and may have been more widespread than previously thought.”
Dr Dave Martill from the University’s School of Earth & Environmental Sciences, said: "This significant discovery demonstrates how young scientists can make an impact on our knowledge and emphasises how much field work remains to be done and how many exciting discoveries are left to unearth."
