Hemoglobin-derived porphyrins preserved in a Middle Eocene blood-engorged mosquito
- Departments of aPaleobiology and
- bMineral Sciences, National Museum of Natural History, Washington, DC 20013;
- cGeophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015;
- dDepartment of Chemistry, Materials, and Surfaces, SP Technical Research Institute of Sweden, 501 11 Borås, Sweden; and
- eDepartment of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
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Edited by Michael S. Engel, University of Kansas, Lawrence, KS, and accepted by the Editorial Board September 18, 2013 (received for review June 7, 2013)
Significance
Fossils, in addition to documenting the existence of extinct species, can often provide information on the behavior of ancient organisms. The present study describes the fossil of a blood-engorged mosquito in oil shale from northwestern Montana. The existence of this rare specimen extends the existence of blood-feeding behavior in this family of insects 46 million years into the past. Heme, the oxygen-carrying group of hemoglobin in the host’s blood, was identified in the abdomen of the fossil mosquito by nondestructive mass-spectrometry analysis. 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.
Abstract
Although hematophagy is found in ∼14,000 species of extant insects, the fossil record of blood-feeding insects is extremely poor and largely confined to specimens identified as hematophagic based on their taxonomic affinities with extant hematophagic insects; direct evidence of hematophagy is limited to four insect fossils in which trypanosomes and the malarial protozoan Plasmodium have been found. Here, we describe a blood-engorged mosquito from the Middle Eocene Kishenehn Formation in Montana. This unique specimen provided the opportunity to ask whether or not hemoglobin, or biomolecules derived from hemoglobin, were preserved in the fossilized blood meal. The abdomen of the fossil mosquito was shown to contain very high levels of iron, and mass spectrometry data provided a convincing identification of porphyrin molecules derived from the oxygen-carrying heme moiety of hemoglobin. These data confirm the existence of taphonomic conditions conducive to the preservation of biomolecules through deep time and support previous reports of the existence of heme-derived porphyrins in terrestrial fossils.
Footnotes
- ↵1To whom correspondence should be addressed. E-mail: GreenwaltD{at}si.edu.
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Author contributions: D.E.G. designed research; D.E.G., Y.S.G., S.M.S., T.R., and R.E.H. performed research; D.E.G., Y.S.G., S.M.S., T.R., and R.E.H. analyzed data; and D.E.G. wrote the paper.
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The authors declare no conflict of interest.
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This article is a PNAS Direct Submission. M.S.E. is a guest editor invited by the Editorial Board.
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See Commentary on page 18353.
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This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1310885110/-/DCSupplemental.
