The 46-million-year-old meal: Scientists discover mosquito fossil so well-preserved that it still has blood in its stomach
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- The mosquito perished soon after feeding in the Middle Eocene and its body has been trapped in shale ever since
- A team of international researchers used non-destructive mass spectrometry to create a chemical picture of the mosquito's stomach contents
- The find extends the fossil record of blood-feeding in this family of insects by 46 million years
Blood sucked by a mosquito that died 46 million years ago has been discovered by scientists.
Researchers used a new technique to determine the nature of the animal's last meal to prove that the insects have been feeding on blood all this time and could even have feasted on dinosaurs.
The mosquito that was discovered perished soon after feeding in the Middle Eocene and its body has been trapped in shale ever since.
The animal died when the spectacular mountain ranges in Montana, where it was dug up, had just finished forming.
The ancient insect was so well-preserved because it had been trapped in shale - a type of mudstone in which organic remains decompose much more slowly - and the soft mud material that surrounded it compressed the creature's body without distorting it.
The fine grain size of shale also preserves more details and the process of fossilisation is much like holding the fossil flat and pressing it like a book protects a dried flower.
Paleobiologist Dr Dale
Greenwalt, a researcher at the Smithsonian's National History Museum,
who led the study, used a state-of-the-art technology called
non-destructive mass spectrometry to produce a detailed chemical picture
of the mosquito's stomach contents.
The findings show the insects have been feeding on blood for millions of years and around 14,000 living insect species including fleas, ticks and modern mosquitoes feed on blood today.
Although this feeding strategy appears to have evolved independently across a variety of animals, fossil evidence of this behaviour is extremely rare.
The find extends the fossil record of blood-feeding in this family of insects by 46 million years, according to Dr Ralph Harbach, a researcher at the Natural history Museum in London who was involved with the study.
After finding high levels of iron in the fossilised insect's abdomen, the researchers analysed the specimen and identified the source as haem - the protein in the blood responsible for the transport of oxygen.
Although large and fragile molecules such as DNA generally do not survive fossilisation, the mosquito proves certain complex organic molecules such as haem can be preserved.
It was one of two mosquitoes discovered in the shale deposits that reveal just how remarkably little the parasites have changed in the last 46 million years.
The new fossils - one female and the other male - are so detailed scientists were able to determine they represent two previously unknown species.
The female, named Culiseta lemniscata, had eaten the blood meal. The male has been named Culiseta kishenehn.
Their fossils contain details as intricate as wing veins, sexual organs, scales and hair-like structures on the wings.
Dr Greenwalt and colleagues, whose findings are published in Proceedings of the National Academy of Sciences, said the preservation of the fossil was 'extremely improbable'.
'The insect had to take a blood meal, be blown to the water's surface and sink to the bottom of a pond or similar structure to be quickly embedded in fine sediment - all without disruption of its fragile distended blood-filled abdomen.'
He said it is not surprising that it is the first discovery of its kind despite the misconception of dinosaur DNA recovery from mosquitoes preserved in amber popularised by Jurassic Park twenty years ago.
'The existence of this rare specimen extends the existence of blood-feeding behaviour in this family of insects 46 million years into the past,' Dr Greenwalt said.
'This is the only known fossil of a blood-engorged mosquito ever found and represents the first clear evidence that some organic molecules can be preserved in a fossil of this age.
'We made the assumption that genetic material like DNA was not preserved. We didn’t even attempt to look at it because DNA degrades very quickly.
'Without question there are probably other things contained in this fossil. We just don’t know what they might be,' he added.
Read more: http://www.dailymail.co.uk/sciencetech/article-2458610/Mosquito-fossil-preserved-blood-stomach.
Researchers used a new technique to determine the nature of the animal's last meal to prove that the insects have been feeding on blood all this time and could even have feasted on dinosaurs.
The mosquito that was discovered perished soon after feeding in the Middle Eocene and its body has been trapped in shale ever since.
Researchers used a new technique to determine
the nature of the mosquito's last meal to prove that the insects have
been feeding on blood all this time and could even have feasted on
dinosaurs. The creature's fossilised body (pictured) has been trapped in
shale for 46 millions years
The animal died when the spectacular mountain ranges in Montana, where it was dug up, had just finished forming.
The ancient insect was so well-preserved because it had been trapped in shale - a type of mudstone in which organic remains decompose much more slowly - and the soft mud material that surrounded it compressed the creature's body without distorting it.
The fine grain size of shale also preserves more details and the process of fossilisation is much like holding the fossil flat and pressing it like a book protects a dried flower.
More...
The findings show the insects have been feeding on blood for millions of years and around 14,000 living insect species including fleas, ticks and modern mosquitoes feed on blood today.
Although this feeding strategy appears to have evolved independently across a variety of animals, fossil evidence of this behaviour is extremely rare.
The find extends the fossil record of blood-feeding in this family of insects by 46 million years, according to Dr Ralph Harbach, a researcher at the Natural history Museum in London who was involved with the study.
Dr Dale Greenwalt used non-destructive mass
spectrometry to produce a detailed chemical picture of the mosquito's
stomach contents. The findings show the insects have been feeding on
blood for millions of years and around 14,000 living insect species
including fleas, ticks and modern mosquitoes (pictured) feed on blood
today
After finding high levels of iron in the fossilised insect's abdomen, the researchers analysed the specimen and identified the source as haem - the protein in the blood responsible for the transport of oxygen.
Although large and fragile molecules such as DNA generally do not survive fossilisation, the mosquito proves certain complex organic molecules such as haem can be preserved.
It was one of two mosquitoes discovered in the shale deposits that reveal just how remarkably little the parasites have changed in the last 46 million years.
The new fossils - one female and the other male - are so detailed scientists were able to determine they represent two previously unknown species.
The female, named Culiseta lemniscata, had eaten the blood meal. The male has been named Culiseta kishenehn.
Their fossils contain details as intricate as wing veins, sexual organs, scales and hair-like structures on the wings.
Dr Greenwalt said it's not surprising that it is
the first discovery of its kind despite the misconception of dinosaur
DNA recovery from mosquitoes preserved in amber popularised by Jurassic
Park twenty years ago - Richard Attenborough in the film is pictured
Dr Greenwalt and colleagues, whose findings are published in Proceedings of the National Academy of Sciences, said the preservation of the fossil was 'extremely improbable'.
'The insect had to take a blood meal, be blown to the water's surface and sink to the bottom of a pond or similar structure to be quickly embedded in fine sediment - all without disruption of its fragile distended blood-filled abdomen.'
He said it is not surprising that it is the first discovery of its kind despite the misconception of dinosaur DNA recovery from mosquitoes preserved in amber popularised by Jurassic Park twenty years ago.
'The existence of this rare specimen extends the existence of blood-feeding behaviour in this family of insects 46 million years into the past,' Dr Greenwalt said.
'This is the only known fossil of a blood-engorged mosquito ever found and represents the first clear evidence that some organic molecules can be preserved in a fossil of this age.
'We made the assumption that genetic material like DNA was not preserved. We didn’t even attempt to look at it because DNA degrades very quickly.
'Without question there are probably other things contained in this fossil. We just don’t know what they might be,' he added.
Read more: http://www.dailymail.co.uk/sciencetech/article-2458610/Mosquito-fossil-preserved-blood-stomach.
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