redOrbit Staff & Wire Reports – Your Universe Online
Researchers report that they have found a fossilized mosquito specimen that was still blood-engorged from its last meal – a discovery that is detailed in the latest edition of the journal Proceedings of the National Academy of Sciences.
The mosquito had been preserved in shale rock for approximately 46 million years after it plummeted into a lake in what is now northwestern Montana, according to Joseph Stromberg of Smithsonian.com. Perhaps the most astonishing thing about the discovery is that it isn’t exactly new. It was originally located by an amateur fossil hunter three decades ago, and had been sitting in a basement ever since.
The blood-engorged mosquito fossil may have been lost forever had it not been for Dale Greenwalt, a retired biochemist who has been helping collect fossils in the western US for the Smithsonian Museum of Natural History since 2006. Greenwalt met with a family in Whitefish, Montana, and after they heard about his work they decided to donate their personal fossil collection to the institution. It was when he was going through that family’s fossils that he discovered the unique-looking mosquito.
“I immediately noticed it – it was obvious that it was different,” he explained. The fossilized insect had what Stromberg described as a “darkly opaque abdomen,” and Greenwalt believed that it might contain several-million-year-old blood. Staff from the Natural History Museum’s mineral sciences lab used energy dispersive X-ray spectroscopy and other scanning techniques to analyze the specimen in detail, and determined that his hunch was correct.
“Using two different types of light-refracting x-rays that determine what chemicals are present, Greenwalt and colleagues determined that the female mosquito’s belly was full of iron, a major feature of blood that gets oxygen to the rest of the body,” reports AP Science Writer Seth Borenstein. “Iron levels were higher than elsewhere in her body and anywhere on a non-biting male used as a control subject.”
The researchers then discovered evidence of porphyrins, a group of organic compounds which are bound to iron in blood. All together, their findings help provide “a definitive case” that the mosquito had 46-million-year-old blood in its system. However, North Carolina State University professor Mary Schweitzer is not completely convinced. She told Borenstein that the findings were preliminary, and that the Smithsonian Museum of Natural History team did not actually rule out all other possibilities before reaching their conclusion.
If it is actually blood in the mosquito’s system, it wouldn’t be used to bring back dinosaurs (ala Jurassic Park) or another other long-dead creature, the researchers said. For one thing, dinosaurs would have been long extinct before the mosquito was even born, Borenstein said. Also, even if there was DNA from some long-dead creature in the insect’s system, Stromberg pointed out that there are multiple technical issues that would prevent the type of cloning process featured in the movie from being used in real life.
“Assembling a full genome from DNA fragments requires us to have an understanding of what the whole genome looks like (which we don’t have in this case), and turning that into a living, breathing animal would necessitate putting that DNA into an ovum of a living species very closely related to the mystery creature that we don’t know in the first place,” he wrote. “So, alas, no resurrected ancient creatures will roam free thanks to this new find. Still, the find is scientifically significant, helping scientists better understand the evolution of blood-feeding insects.”
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