SYDNEY: The fossilised remains of a new species of giant bird have been discovered, indicating that life in the Cretaceous period was far more diverse than ever imagined.
Uncovered in Kazakhstan, the remains of the 85-million-year-old species, named Samrukia nessovi, are limited to the two halves of the animal’s lower jaw. The jaw specimen is well preserved and at just over 30 cm long, represents an animal that could have stood 3 m tall and weighed up to 50 kg – if it was flightless. Samrukia represents one of the biggest known bird species from this period.
“The fact that giant birds were living in Late Cretaceous Central Asia is itself a neat discovery: it provides more information on the composition of Central Asian Cretaceous communities,” said Darren Naish from the University of Portsmouth in the UK, co-author of the paper published in the current issue of Biology Letters.
The Kazakh phoenix
Prior to this discovery, of the 100 species of Mesozoic birds known, only one was large-bodied. Found in France and named in 1998, Gargantuavis philoinos was the sole giant terrestrial bird known, with the vast majority weighing less than 2 kg, and comparable in size to modern finches, thrushes and crows.
The specimen was found in the Kyzylorda District of Kazakhstan during the 1980s and ended up in the Royal Belgian Institute of Natural Sciences in Brussels. In 2010, palaeontologist and dinosaur expert at the institute, Pascal Godefroit, identified it as being unusual, and called together a team to examine it.
“Loads of neat specimens get discovered this way (that is, in museum collections)… there is tonnes of material in museums worldwide that hasn’t been studied or analysed properly, and not that many palaeontologists going ’round studying it all,” said Naish.
The generic name of the species is a nod to Samruk, a mythological Kazakh phoenix, while its specific name, nessovi, honours the late Lev Nessov, a Russian palaeontologist who, before his death in 1995, made a valuable contribution to Central Asian vertebrate palaeontology.
But could this giant fly?
Due to the fact that they only have a lower jaw fragment to work with, the researchers are reluctant to speculate on the behaviour of Samrukia, and cannot confirm whether or not it could fly.
“We only have the lower jaw, and it just isn’t possible to say from this whether Samrukia could fly or not. The majority of birds of this time were capable of flight, but flightlessness was present in several bird lineages of this time. It’s therefore totally plausible that Samrukia was flightless,” said Naish. “The idea that it might have been flightless comes entirely from its large size – as we know from the modern world, the really big birds (like ostriches, emus and dodos) are often flightless.”
According to Naish, if Samrukia could fly, it could have been a large, condor-shaped bird with a giant wingspan of up to four metres and could have weighed at least 12 kg. But flightessness would have afforded it more room to grow, so a flightless Samrukia could have weighed up to 50 kg.
Keeping guesses conservative
“They [the researchers] have quite rightly been very conservative, the suggested size ranges from a few kilos up to tens of kilos or maybe more, it really does depend on whether it could fly or not,” said Stephen Wroe from the University of New South Wales, who discovered an extinct terror bird in late 2010.
“This is such a different group of birds, so you really would be dancing off into wild speculation to say anything definite about it,” he added.
Wroe said it would be interesting to look at CT scans of the specimen to see whether the internal structure of the jaw was preserved. If Samrukia was a flying bird, it should have the lightweight structure required by a flying animal.
What makes modern birds so successful?
According to Naish, the discovery of Samrukia is significant because it provides more evidence for diversity in birds that are outside Neornithes, the ‘modern bird’ group. Neornithes are the only known group of birds that have survived to the present day, and scientists thought that no other bird lineages had evolved the kind of diversity that characterises this highly successful group.
“We’re now finding that non-neornithines were surprisingly diverse, and in some respects not at all different from neornithines. Most of the giant birds that have evolved throughout history have been neornithines, yet Samrukia (and Gargantuavis) are not,” said Naish.
Samrukia is evidence that giant size, and the lifestyle and behaviours that are influenced by that, evolved in other bird lineages. Naish described this as “interesting”, as alaeontologists had put the survival of the neornithines across the Cretaceous-Paleogene boundary (65 million years ago) down to their superior adaptability and diverse anatomy. “Samrukia provides an indication that things weren’t this simple, since it shows that non-neornithine lineages were more diverse and perhaps more adaptable than sometimes thought,” he said.