1 May 2012
Inch-long fleas tormented dinosaurs
by Will Parker
Ten times bigger than their modern cousins, prehistoric flea fossils unearthed by Chinese scientists reveal a proboscis like a hypodermic needle. The new discovery is detailed in the journal Current Biology.
"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, professor emeritus of zoology at Oregon State University, who wrote a commentary on the find in the same journal. "These are really well-preserved fossils that give us another glimpse of life into the really distant past, the Cretaceous and Jurassic."
Poinar said it's possible that the fossilized soft-bodied, flea-like insects found in Inner Mongolia (artist's impression above) 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 more resembled 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.
Modern fleas are adapted to feeding on warm-blooded vertebrates, Poinar notes, and today the majority of the 2,300 known species attack mammals, while the remainder feed on birds. But the unusual characteristics of the creatures found in the new fossils lead scientists to believe they preyed on dinosaurs, feeding on the softer skin between scales.
Scientists think that the giant flea may have snuck up on dinosaurs while they slept, crawling onto their soft underbellies and then giving them a bite that would have felt like a needle going in. "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 - a flea shot, if not a flu shot."
Source: Oregon State University