Sunday, October 30, 2011

Archaeopteryx was first bird after all

October 26, 2011 Archaeopteryx was first bird after allEnlarge
Archaeopteryx fossil (Creative Commons - Wikipedia)
( -- The crown of the famous 150-million-year-old Archaeopteryx fossil as the first bird has been restored by a new evolutionary tree.
In a study published today in the journal Biology Letters, Australian researchers say the feathered fossil is indeed of the first known bird, despite another study earlier this year suggesting otherwise.

had been considered for 150 years to be the first known bird since the first complete specimen was found in Germany in 1861, revealing a combination of reptilian and and bird features.  But Chinese researchers asserted recently that a new and closely related fossil, Xiaotingia zhengi, was a bird-like dinosaur - therefore suggesting that Archaeopteryx was also a dinosaur.

However, the new study, led by Dr Michael Lee, of the South Australian Museum, used a more detailed analyis to show that Archaeopteryx was a bird.

"Archaeopteryx is iconic in palaeontology as the basal bird, however the plethora of discoveries of feathered dinosaurs in China, in particular, has progressively eroded the distinction of just what defines a bird," says one of the authors, Dr Trevor Worthy, a palaeontologist in the UNSW School of Biological, Earth and Environmental Sciences.

"This trend came to a head when Xaiotingia was analysed most recently and in the analysis presented Archaeopteryx was found to jump ship as it were from the birds to the dromaeosaurs.

"This sensational result was presented and attracted much publicity, but the very weak statistical support for this new relationship was not given due consideration.

"In our work, Mike Lee has shown quite clearly that methodology is highly significant and that before a paradigm is overturned data needs to be rigorously examined.

"Using a different analytical methodology than that usually used by morphologists, but one always used by analysts of molecular data, we found that Archaeopteryx remains the basal bird and does so with strong statistical support.

"This case demonstrates that multiple analysis methods should be used, each with concordant results before a paradigm breaking result is accepted. And it shows that Archaeopteryx remains the key to understanding the origin of birds."

More information: http://rsbl.royals … tent/current
Provided by University of New South Wales


Monday, October 17, 2011

Which NZ coastal species really are native?

Prof Jon Waters takes a close look at a stuffed yellow-eyed penguin at the Otago Museum. Photo: Peter McIntosh
Prof Jon Waters takes a close look at a stuffed yellow-eyed penguin at the Otago Museum. Photo: Peter McIntosh
It has been third time lucky for University of Otago zoologist Prof Jonathan Waters as he starts investigating whether some of our native coastal species, including the yellow-eyed penguin, really are native. Prof Waters said it was "great" that an $878,000 grant which he had recently received from the Marsden Fund would enable him to investigate how animals responded to human impacts, and how many of New Zealand's coastal species were actually new arrivals from overseas.
Yellow-eyed penguins, for instance, apparently arrived in New Zealand only in the past 500 years, replacing a prehistoric penguin species, the waitaha, that was wiped out shortly after human settlement, he said.
One of his former Otago PhD students, Dr Sanne Boessenkool, undertook earlier research several years ago and discovered remains of the extinct waitaha penguin.
It is suggested that some yellow-eyed penguins made their way north from their native Auckland Islands and Campbell Island and later established themselves on the Otago Peninsula and elsewhere on the Otago coast after the waitaha penguin became extinct.
Many people would be surprised the yellow-eyed penguin may not have been living in Otago as long as previously believed, he said.
"We tend to think that things that are here now are things that have been here for a long time," Prof Waters said.
The kind of extinction-recolonisation events apparently involved with such penguins may be the rule rather than the exception in coastal New Zealand, including with sea-lions and little blue penguins, he said.
It was "great" to be able to pursue the research, after two earlier recent attempts to gain Marsden funding for the project had been unsuccessful.
The little blue penguins which had now established themselves on the Otago coast, after earlier being largely wiped out by humans, were in fact penguins from Australia.
They were different from endemic little blue penguins found elsewhere on the New Zealand mainland.
New Zealand sea lions found on the Otago coast were also not the same creatures that once previously existed there, but were apparently a replacement population from the subantarctic islands, researchers said.
Collaborators in the project are Prof Lisa Matisoo-Smith, of the Otago anatomy department, and Dr Paul Scofield, of the Canterbury Museum.
The researchers will use carbon dating and state-of-the-art DNA analysis of prehistoric bones to shed further light on the country's "dramatic biological history", and to conduct a biological audit of prehistoric New Zealand.
Archaeologists would be teaming up with geneticists, in order to "reveal exciting aspects of New Zealand's past - stories that were previously impossible to tell," he said.