Dinosaurs Had Fleas Too - Giant Ones, Fossils Show

By Seth Borstein

Washington - In the Jurassic era, even the flea was a beast, compared to its minuscule modern descendants. These pesky bloodsuckers were nearly an inch long.

New fossils found in China are evidence of the oldest fleas — from 125 million to 165 million years ago, said Diying Huang of the Nanjing Institute of Geology and Paleontology. Their disproportionately long proboscis, or straw-like mouth, had sharp weapon-like serrated edges that helped them bite and feed from their super-sized hosts, he and other researchers reported Wednesday in the journal Nature.

Scientists figure about eight or more of today's fleas would fit on the burly back of their ancient ancestor.

"That's a beast," said study co-author Michael Engel, entomology curator at the Natural History Museum at the University of Kansas. "It was a big critter. I can't even imagine coming home and finding my miniature schnauzer with one or more of these things crawling around on it."

The ancient female fleas were close to twice the size of the males, researchers found, which fits with modern fleas.

But Engel said it's not just the size that was impressive about the nine flea fossils. It was their fearsome beak capable of sticking into and sucking blood from the hides of certain dinosaurs, probably those that had feathers.

These flea beaks "had almost like a saw running down the side," Engel said. "This thing was packing a weapon. They were equipped to dig into something."

While the ancient fleas were big, they had one disadvantage compared to modern ones: Their legs weren't too developed. Evolving over time, fleas went from crawling to jumping, Huang said.

"Luckily for the land animals of the Mesozoic, these big flat fleas lacked the tremendous jumping capacity that our common fleas have," said Joe Hannibal of the Cleveland Museum of Natural History. He wasn't involved in the study, but praised it as useful and interesting.

Just finding the fleas was a stroke of luck, Huang said. He first found one in a Chinese fossil market and mentioned it to someone at his hotel. The other guest showed him a photo of another fossilized flea, telling him it was from Daohugou in northeastern China, where there's a famous fossil bed from about 165 million years ago. Huang went there and found fleas preserved in a brownish film of volcanic ash. The grains of rock were so fine you could see antennae and other details of the fleas, he said.

Modern fleas get engorged after they feast on blood, but these didn't seem engorged, Engel said.

It shouldn't seem too surprising that there were large fleas more than 100 million years ago. If you go back even farther in time, ancestors of dragonflies and damsel flies had 3-foot wingspans, Engel said.

Now You See It, Now You Don't: Time Cloak Created

By Seth Borenstein

WASHINGTON — It's one thing to make an object invisible, like Harry Potter's mythical cloak. But scientists have made an entire event impossible to see. They have invented a time masker.

Think of it as an art heist that takes place before your eyes and surveillance cameras. You don't see the thief strolling into the museum, taking the painting down or walking away, but he did. It's not just that the thief is invisible — his whole activity is.

What scientists at Cornell University did was on a much smaller scale, both in terms of events and time. It happened so quickly that it's not even a blink of an eye. Their time cloak lasts an incredibly tiny fraction of a fraction of a second. They hid an event for 40 trillionths of a second, according to a study appearing in Thursday's edition of the journal Nature.

We see events happening as light from them reaches our eyes. Usually it's a continuous flow of light. In the new research, however, scientists were able to interrupt that flow for just an instant.

Other newly created invisibility cloaks fashioned by scientists move the light beams away in the traditional three dimensions. The Cornell team alters not where the light flows but how fast it moves, changing in the dimension of time, not space.

They tinkered with the speed of beams of light in a way that would make it appear to surveillance cameras or laser security beams that an event, such as an art heist, isn't happening.

Another way to think of it is as if scientists edited or erased a split second of history. It's as if you are watching a movie with a scene inserted that you don't see or notice. It's there in the movie, but it's not something you saw, said study co-author Moti Fridman, a physics researcher at Cornell.

The scientists created a lens of not just light, but time. Their method splits light, speeding up one part of light and slowing down another. It creates a gap and that gap is where an event is masked.

"You kind of create a hole in time where an event takes place," said study co-author Alexander Gaeta, director of Cornell's School of Applied and Engineering Physics. "You just don't know that anything ever happened."

This is all happening in beams of light that move too fast for the human eye to see. Using fiber optics, the hole in time is created as light moves along inside a fiber much thinner than a human hair. The scientists shoot the beam of light out, and then with other beams, they create a time lens that splits the light into two different speed beams that create the effect of invisibility by being too fast or too slow. The whole work is a mess of fibers on a long table and almost looks like a pile of spaghetti, Fridman said.

It is the first time that scientists have been able to mask an event in time, a concept only first theorized by Martin McCall, a professor of theoretical optics at Imperial College in London. Gaeta, Fridman and others at Cornell, who had already been working on time lenses, decided to see if they could do what McCall envisioned.

It only took a few months, a blink of an eye in scientific research time.

"It is significant because it opens up a whole new realm to ideas involving invisibility," McCall said.

Researchers at Duke University and in Germany's Karlsruhe Institute of Technology have made progress on making an object appear invisible spatially. The earlier invisibility cloak work bent light around an object in three dimensions.

Between those two approaches, the idea of invisibility will work its way into useful technology, predicts McCall, who wasn't part of either team.

The science is legitimate, but it's still only a fraction of a second, added City College of New York physicist Michio Kaku, who specializes in the physics of science fiction.

"That's not enough time to wander around Hogwarts," Kaku wrote in an email. "The next step therefore will be to increase this time interval, perhaps to a millionth of a second. So we see that there's a long way to go before we have true invisibility as seen in science fiction."

Gaeta said he thinks he can get make the cloak last a millionth of a second or maybe even a thousandth of a second. But McCall said the mathematics dictate that it would take too big a machine — about 18,600 miles long — to make the cloak last a full second.

"You have to start somewhere and this is a proof of concept," Gaeta said.

Still, there are practical applications, Gaeta and Fridman said. This is a way of adding a packet of information to high-speed data unseen without interrupting the flow of information. But that may not be a good thing if used for computer viruses, Fridman conceded.

There may be good uses of this technology, Gaeta said, but "for some reason people are more interested in the more illicit applications."