WASHINGTON (AP) -- In the Jurassic era, even the flea was a beast, compared to its minuscule modern descendants. These pesky bloodsuckers were nearly an inch (25 millimeters) 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.
Engel said it is not just the size, however, 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 were not well 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 was not involved in the study, but he 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 is 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 did not seem engorged, Engel said.
It should not seem very surprising that large fleas existed more than 100 million years ago. If you go back even farther in time, ancestors of dragonflies and damsel flies had 3-foot-long (1 meter-long) wingspans, Engel said.
초거대 공룡 벼룩 발견
몸 크기가 풍뎅이만한 1억6천500만~1억2천500만년 전의 공룡 벼룩 화석이 중국에서 발견됐다.
중국과 미국 과학자들은 네이멍구(內蒙古) 자치구 내 쥐라기 화석 유적지 다오 후거우의 화산재 속에서 발굴한 벼룩 화석들의 몸 크기가 2.5㎝에 가까워 오늘날 벼룩의 8배나 되는데다 공룡의 가죽도 뚫을 수 있을 만큼 강력한 주둥이를 가진 것으 로 밝혀졌다고 29일 네이처지 최신호에 발표했다.
빨대처럼 생긴 이들 벼룩의 긴 주둥이 가장자리는 톱니 모양으로 돼 있어 거대 한 숙주 동물의 몸을 물어뜯고 피를 빨 수 있는 구조로 밝혀졌다.
연구진은 "이 벼룩들은 야수라고 불러도 좋을 정도"라면서 크기가 문제가 아니 라 깃털로 덮인 공룡들의 가죽을 뚫고 피를 빨 수 있을 정도의 무기인 주둥이가 공 포의 대상이라고 밝혔다.
이들은 고대 벼룩의 주둥이는 옆에 톱날이 죽 달려 있는 것과 비슷하다면서 이 는 무언가를 파고드는 용도라고 지적했다.
그러나 고대 벼룩의 다리는 지금처럼 발달하지 않아 예전엔 기어다니다가 점점 뛰어다니는 쪽으로 진화한 것으로 보이며 피를 실컷 먹고 난 뒤에 충혈되는 요즘 벼 룩과 달리 충혈되지 않는 것으로 보인다고 학자들은 밝혔다.
연구진은 잠자리나 실잠자리 조상의 날개폭이 1m나 됐던 만큼 이처럼 큰 쥐라기 벼룩의 존재는 특별히 놀랄 일은 아니라고 말했다.
학자들은 화석 시장에 매물로 나온 벼룩의 사진을 보고 출처를 역추적한 뒤 다 오후거우 화석 유적지를 찾아가 고대 벼룩 9마리를 찾아내는 행운을 누렸다.