Senin, 07 Mei 2012

So that's why they were so bad-tempered: Fleas were an INCH-long when dinosaurs roamed

So that's why they were so bad-tempered: Fleas were an INCH-long when dinosaurs roamed

By Rob Waugh
UPDATED: 11:47 EST, 7 May 2012

Fleas

Thankfully, the fleas - found in Inner Mongolia, and analysed by experts at Oregon State University - seem not to be an ancestor's flea, but instead a separate breed of monster that has since died out

What kind of insect would have dared to crawl over the bodies of dinosaurs, plunging its proboscis between their scales to drink blood?

Answer: a flea-like insect 10 times the size of ones today, with a bite that would have felt like a hypodermic syringe.

Thankfully, the fleas - found in Inner Mongolia, and analysed by experts at Oregon State University - seem not to be an ancestor's flea, but instead a separate breed of monster that has since died out.

‘These were insects much larger than modern fleas and from the size of their proboscis we can tell they would have been mean,’ said George Poinar, Jr., a professor emeritus of zoology at Oregon State University, who wrote a commentary on this find in the same journal.

‘You wouldn't talk much about the good old days if you got bit by this insect,’ Poinar said. ‘It would have felt about like a hypodermic needle going in. We can be thankful our modern fleas are not nearly this big.’

Poinar, who is an international expert in ancient and extinct insect life forms, said it's possible that the soft-bodied, flea-like insects found in these fossils from Inner Mongolia are the evolutionary ancestors of modern fleas, but most likely they belong to a separate and now extinct lineage.

Called Pseudopulex jurassicus and Pseudopulex magnus, they had bodies that were more flat, like a bedbug or tick, and long claws that could reach over scales on the skin of dinosaurs so they could hold onto them tightly while sucking blood.

Modern fleas are more laterally compressed and have shorter antennae, and are able to move quickly through the fur or feathers of their victims.

‘These are really well-preserved fossils that give us another glimpse of life into the really distant past, the Cretaceous and Jurassic,’ said Poinar, who has also studied ‘younger’ fleas from 40-50 million years ago preserved in amber.

Giant female (left) and male (right) fleas from the Middle Jurassic. Scientists believe they may have fed on feathered dinosaurs

Giant female (left) and male (right) fleas from the Middle Jurassic. Scientists believe they may have fed on feathered dinosaurs

Why the fleas were so large, and armed with such powerful weaponry, is a puzzle, because only small shrew-like mammals existed during the Jurassic and early Cretaceous periods.

Modern fleas feed exclusively on animals with fur and feathers.

One possibility is that the insects fed on feathered dinosaurs, a number of which have been discovered in China.

The largest females were 20.6 millimetres (0.81in) long, while males grew to 14.7 millimetres (0.58in).

Besides being much larger than modern fleas, they lacked their characteristic jumping hind legs.

One group of fleas from Ningcheng County, Inner Mongolia, dated back to the Middle Jurassic period 165 million years ago.

The other, from Liaoning Province, was 40 million years younger from the Lower Cretaceous period.


Feathered Deinonychus dinosaurs in the early Cretaceous. Scientists speculate that the fleas could have evolved their large, toughened mouthpieces specifically to penetrate dinosaurs' scaly hides

Feathered Deinonychus dinosaurs in the early Cretaceous. Scientists speculate that the fleas could have evolved their large, toughened mouthpieces specifically to penetrate dinosaurs' scaly hides


The scientists, led by Dr Andre Nel, from the Museum of Natural History in Paris, France, wrote: ‘The early mammals were small animals, making the large size of these Mesozoic species and the robustness of their mouthparts seem mismatched.

‘It is possible that the hosts of these early fleas were among the feathered dinosaurs of the period that became well known from the same deposits.’

As placental mammals evolved and diversified, so did the fleas that fed on them, ‘eventually giving rise to the plague-carrying species that have so markedly altered the course of human history’, the researchers added.

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yuk!

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THEY EVOLVED INTO BLOOD SUCKING TORIES

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Imagine one of these one your cat or dog.

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20.6 millimetres equals 2.06 centimetres or cm which is a more convenient unit in this case. 1cm equals 10 mm(milimetres)

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Blood sucking insects?........Sounds very much like the EU parliament.

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