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In todays
SMH:
Penguin ancestor
revealed - James Randerson in
London
SCIENTISTS have
uncovered fossils which reveal the ancestor of the penguin to be a fearsome
beast far removed from the waddling bird in dinner-suit plumage which has
endeared itself to cinema audiences.
The fossils, which were found in Peru, suggest a creature that
was more than 1.5 metres tall and weighed as much as a human.
The 36 million-year-old tropical bird's intimidating appearance
was topped off with powerful arms, a chunky neck and a potentially vicious
18-centimetre beak.
"It's a monster," said Professor Julia Clarke, of North Carolina
State University, who described the fossils with her team in Proceedings of
the National Academy of Sciences.
The discovery of the giant bird has shaken scientists'
understanding of penguin evolution. The find indicates that penguins made the
journey to equatorial regions much earlier in their evolutionary history than
researchers realised.
And because the penguins lived during a period when the planet
was experiencing a "greenhouse" climate, the pair of species that have been
discovered are challenging what researchers thought they knew about how species
adapt to hotter temperatures.
The giant species has been named Icadyptes salasi. If it
were alive today, it would tower over the largest penguins on the planet, the
1.2-metre emperors, whose epic migration across the Antarctic wilderness to
bring food to their chicks was celebrated in the film March of the
Penguins.
"The bone preservation is extremely good," Professor Clarke
said.
The detail is so clear that researchers were able to see fine
patterning on the beak of the giant penguin left by a sheet of keratin, the
material that makes up feathers.
The team does not have any direct evidence for the new
discovery's diet, but the wings were adapted for swimming and found in sediments
laid down just off shore. Its elongated beak would have been capable of snaring
large fish, but its shape is unusual.
"It is distinct from anything we have in living penguins,"
Professor Clarke said.
Attachment points for neck muscles are also large, suggesting it
had a powerful neck for spearing prey.
The discovery goes against the general rule that as climatic
conditions get warmer, species tend to evolve into a smaller body
size.
The theory is that large size is useful in the cold because it
reduces the ratio of surface area to volume, making it easier to conserve heat.
But Icadyptes salasi was found in a region that resembled the modern-day
Atacama Desert in Chile.
The find contradicts the idea that penguins did not reach
equatorial regions until 4 million to 8 million years ago, well after a cooling
period had set in that began to swell the polar icecaps. Today, only one
species, the Humboldt penguin, is found on the coast of Peru.
The team is keen to point out that although these species were
adapted to the tropics, it does not mean that current penguin species will be
able to adapt quickly to climate change.
"Current global warming is occurring on a significantly shorter
time scale," Professor Clarke said.
Guardian News & Media
http://www.smh.com.au/news/science/penguin-ancestor-revealed/2007/06/26/1182623909227.html
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