Mosquito Fossil Found With Intact Heme from Blood
A blood-gorged mosquito said to be 46 million years old has been found in Montana shale, retaining hemoglobin from its last blood meal.
Calling this an “extremely improbable event,” a female mosquito was fossilized in shale, preserving the red color of its blood-gorged abdomen. Greenwalt et al. from Washington DC and Europe, publishing in PNAS, tested the reddish impressions and found porphyrins derived from hemoglobin, proving the molecules came from blood. A male specimen, which does not engorge blood, was used as a control.
The preservation of fossil female mosquito USNM 559050 was an extremely improbable event. 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 lacustrine structure to be quickly embedded in fine anaerobic sediment, all without disruption of its fragile distended blood-filled abdomen. This fossil has provided a unique opportunity to ask whether or not a portion of the hemoglobin molecule could be preserved after tens of millions of years; heme was the most obvious target for our analysis. Detection of heme-derived porphyrins in the female specimen confirms that it is indeed a blood-engorged mosquito and provides direct evidence of hematophagy in the fossil record.
About porphyrins, the authors state that “Porphyrins are energetically very stable molecules and have been shown to be preserved through geological time as common components of many oil shales.” The authors were sure they had ruled out porphyrins from other sources. They detected heme itself is present, although in a degraded condition.
As support for the longevity of these molecules, the authors referred to the findings of Mary Schweitzer of soft tissue in dinosaur bones:
Blood vessels isolated from trabecular bone of the dinosaur Brachylophosaurus canadensis bound hemoglobin-specific antiserum in an immunosorbant assay, albeit with a signal only twice that of background levels. In immunoblot assays, antiserum raised against extracts of Tyrannosaurus rex trabecular bone reacted with purified hemoglobin but antiserum against hemoglobin did not react with extracts of B. canadensis bone. Both NMR and Raman spectroscopy have been applied to extracts of T. rex trabecular bone tissue, and data from both techniques were suggestive of the presence of heme and/or porphyrin.
If heme could survive in dinosaur bone, it certainly could in a fossil considered half that age. “The data reported herein provide incontrovertible documentation of the presence of heme– and arguably hemoglobin-derived porphyrins in a 46-million-year-old compression fossil and localize the porphyrins to a specific anatomical structure within that fossil.”
PhysOrg summarized the paper, and included an opinion from Mary Schweitzer herself. “Outside expert Mary Schweitzer of North Carolina State University said while the study is exciting and significant, it is preliminary and she thinks Greenwalt’s team didn’t prove their conclusion that it is blood by ruling out all other possibilities.” Most of the PhysOrg article was concerned whether the find supports the Jurassic Park movie scenario of isolating blood DNA from a Jurassic mosquito. Greenwalt et al. stated their opinion on that: “Although large and fragile molecules such as DNA cannot survive fossilization, other complex organic molecules, in this case iron-stabilized heme, can survive intact and provide information relative to the mechanisms of the fossilization process.”
Nature News said the find supports Schweitzer’s claim that hemoglobin was found in dinosaur bone. The chance of finding a blood-gorged abdomen of a mosquito was “infinitesimally small,” the article said, likening the “very fragile” insect part “like a balloon ready to burst.”
This finding, interesting while not spectacular, adds to the long list of evidence of remarkable preservation of original tissue in fossils thought to be tens of millions of years old. Enough of this evidence could tip opinion away from the dogma of long ages. We offer it not as proof, but as support for a growing body of evidence against millions of years. It was not that long ago when fossil-hunters taught that all primordial biological material would have been replaced by stone in just thousands of years. Each of these falsifications of that notion has come as a surprise. From this paper, we have the evolutionists’ word that DNA cannot last long enough to be found in dinosaur bone. Time to look for what the experts consider impossible.