Dinosaur extinction grounded ancient birds

January 21, 2010
Dinosaur extinction grounded ancient birds

(PhysOrg.com) -- An abundance of food and lack of predators following the extinction of dinosaurs saw previously flighted birds fatten up and become flightless, according to new research from The Australian National University.

The study, led by Dr Matthew Phillips, an ARC Postdoctoral Fellow at the ANU Research School of Biology, looked at the mitochondrial genome sequences of the now-extinct giant moa birds of New Zealand. To their surprise, the researchers found that rather than having a flightless relative, their closest relatives are the small flying tinamous of South America.

Their molecular dating study suggests that the ancestors of the African ostrich, Australasian emu plus cassowary, South American rheas and New Zealand moa became flightless independently, in close association with the of the about 65 million years ago.

“Many of the world’s largest flightless birds, known as ratites, were thought to have shared a common flightless ancestor. We followed up on recent uncertainty surrounding this assumption,” said Dr Phillips.

“Our study suggests that the flighted ancestors of ratites appear to have been ground-feeding birds that ran well. So the extinction of the dinosaurs likely lifted predation pressures that had previously selected for flight and its necessary constraint, small size. Lifting of this pressure and more abundant foraging opportunities would then have selected for larger size and consequent loss of flight.”

The finding of independent origins of flightlessness also solves a mystery of how these dispersed across the world over marine barriers - their ancestors flew.

“Ratite have been thought of as relics of the former Gondwanan supercontinent, which combined Africa, South America, Australia, Antarctica, , India and Madagascar,” said Dr Phillips.

“Not only have we shown that the separate ratite lineages evolved too recently to have been on Gondwana before its continents drifted apart, but from our analyses we infer that at least ostriches, and possibly ratites as a whole, have their origins in the northern continents.”

The researchers’ paper, Tinamous and Moa Flock Together: Mitochondrial Analysis Reveals Independent Losses of Flight among Ratites, is published in this month’s issue of the journal Systematic Biology.

Explore further: Trotting with emus, walk with dinosaurs

Related Stories

Trotting with emus, walk with dinosaurs

October 25, 2006

Scientists are watching emus to learn more about dinosaurs that once trotted along a long-lost U.S. coastline during the Middle Jurassic period.

Scientists 'rebuild' giant moa using ancient DNA

July 1, 2009

(PhysOrg.com) -- Scientists have performed the first DNA-based reconstruction of the giant extinct moa bird, using prehistoric feathers recovered from caves and rock shelters in New Zealand.

Extinct New Zealand eagle may have eaten humans

September 11, 2009

(AP) -- Sophisticated computer scans of fossils have helped solve a mystery over the nature of a giant, ancient raptor known as the Haast's eagle which became extinct about 500 years ago, researchers said Friday.

Extinct moa rewrites New Zealand's history

November 18, 2009

(PhysOrg.com) -- The evolutionary history of New Zealand's many extinct flightless moa has been re-written in the first comprehensive study of more than 260 sub-fossil specimens to combine all known genetic, anatomical, geological ...

Recommended for you

Biologists trace how human innovation impacts tool evolution

November 24, 2015

Many animals exhibit learned behaviors, but humans are unique in their capacity to build on existing knowledge to make new innovations. Understanding the patterns of how new generations of tools emerged in prehistoric societies, ...

First Londoners were multi-ethnic mix: museum

November 23, 2015

A DNA analysis of four ancient Roman skeletons found in London shows the first inhabitants of the city were a multi-ethnic mix similar to contemporary Londoners, the Museum of London said on Monday.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Jan 21, 2010
Flight may have contibuted to the extinction of non-flying dinosaurs, by enabling more effective competition for high nutrition seeds and nuts in the upper parts of tall trees. Once birds made it onto the scene, long necks became irrelavent. Without big bodied long neck dinosaurs, big teethed carnivores and scavangers had a harder time of it, hence a general downsizing of size advantage in favor of speed and flight.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.