WASHINGTON-- In a steamy tropical forest 46 millionyears ago, a prehistoric mosquito bit a critter, drew blood and wasblown into a lake in what is now the northwestern state of Montana.Belly full, she died and sank.
Flashforward to the present. Researchers found the minuscule female insectfossilized in a paper-thin piece of shale - which had sat in someone'sbasement for 25 to 30 years with other rocks - and concluded it stillcontains its last supper. A study in the Proceedings of the NationalAcademy of Science reports a first for biology: a blood meal foundintact in a fossil.
While the scenario sounds eerily similar to the Michael Crichton book and movie "Jurassic Park," no new T. rexes will result.
Dinner likely a bird
Unfortunatelyfor would-be dinosaur cloners, the mosquito flew long after dinosaurswent extinct, and its meal was probably blood from a dino descendant, abird. And an even bigger blow to the "Jurassic Park" scenario is thatscientists have long known that DNA from other critters couldn't survivein insect fossils, said study lead author Dale Greenwalt, a retiredbiochemist who collects and analyzes insect fossils from Montana for theSmithsonian Institution.
So this is more a scientific curiosity, a look-what-we-found, that starts out like early chapters of the sci-fi thriller.
"It'sfollowing Crichton's script in that we're using a blood engorged fossilmosquito and in this case we're using the direct descendent of thedinosaurs, given that we're 20 million years late," Greenwalt said.
Iron found in belly
Usingtwo different types of light-refracting X-rays that determine whatchemicals are present, Greenwalt and colleagues determined that thefemale mosquito's belly was full of iron, a major feature of blood thatgets oxygen to the rest of the body. Iron levels were higher thanelsewhere in her body and anywhere on a non-biting male used as acontrol subject. Then the team found evidence of porphyrins, which arebound to iron in blood. Putting the two together makes "a definitivecase" for blood, Greenwalt said.
Outsideexpert Mary Schweitzer of North Carolina State University said whilethe study is exciting and significant, it is preliminary and she thinksGreenwalt's team didn't prove their conclusion that it is blood byruling out all other possibilities.