75 Million-Year-Old Blood Cells Discovered in Dinosaur Bones

By Jon Tennant | June 9, 2015 10:00 am
Theropod dinosaur claw

Theropod claw in which the blood cells were found. Credit: Laurent Mekul

It might sound like something out of Jurassic World but it’s true: Inside fossilized dinosaur bones, researchers have discovered 75-million-year-old red blood cells and proteins.

This discovery indicates that blood and other cells might be preserved much longer in fossils than previously believed. And studying these cells in the future could give us brand-new insights into how dinosaurs looked and behaved.

Preserved Proteins

Scientists’ understanding of dinosaurs has been revolutionized in the last 25 years by the discovery of fossilized soft tissues. We now have evidence for the original material of skin, feathers and feather-like structures, color-bearing organelles, and even muscle fibers and cellular structures found in Tyrannosaurus rex. These have usually been found in exceptionally well-preserved specimens.

Many of these discoveries, however, have been contentious within the paleontological community, and the presence of molecular-level preservation in the fossil record remains controversial. This is because proteins and other molecular components are thought to break down within about four million years.

However researchers Sergio Bertazzo and Susie Maidment found that not only could these structures be preserved for 75 million years, but they could persist in run-of-the-mill museum collections that researchers wouldn’t normally glance twice at.

Dinosaur Cells

The scientists examined fragments from the insides of eight pretty ordinary Cretaceous dinosaur bones from North America. They used a scanning electron microscope to distinguish materials of different density, highlighting several distinct cellular-level structures. In particular, in the claw of a theropod dinosaur the researchers spotted round structures that looked almost exactly like blood cells. In four other specimens, they found fibrous structures that resembled the collagen found in bones of birds.

Scanning electron micrographs of samples from a dinosaur rib. The mineralized fibers are clearly visible. Credit: Sergio Bertazzo

Scanning electron micrographs of samples from a dinosaur rib. The mineralized fibers are clearly visible. Credit: Sergio Bertazzo

Next, to see what the cell-like structures looked like internally, Bertazzo and Maidment used a focused ion beam to strip away incredibly fine layers from them, one by one. They discovered an internal structure within the red blood cells, which based on its size and shape is almost certainly the nucleus. Using another technique, mass spectrometry, they analyzed the chemistry of these structures and found evidence of amino acids (the building blocks of proteins) that were almost identical to those from a living emu.

Finally, in addition to blood cells, the researchers also found 75-million-year-old collagen preserved in its original form. While evidence of collagen before has been found in T. rex, the new findings preserve it in its original folded structure, with aligned and intertwining strands. The researchers report their findings this week in Nature Communications.

What About DNA?

So, dinosaur blood and proteins can be preserved far longer than anyone previously thought possible. What then does that mean for that other fascinating molecule, DNA?

Maidment says that there was no evidence for preserved DNA in the cells they found, so bad news for Jurassic Park fans. But, she continued, “I think it is generally unwise in science to say ‘never.’ Increasingly, studies like ours are showing that original components can be preserved over geological timescales. So perhaps one day DNA fragments might be found in an exceptionally preserved dinosaur fossil.”

Even if that Jurassic Park dream is never realized, the research will give new insights into dinosaurs. Much of what we know has been based on comparison with their descendants, birds, and cousins, crocodiles. Now we have direct evidence that we can begin to use to investigate dinosaurs, as well as other extinct animals, at a whole new level. For example, red blood cell size is known to correlate with metabolic rate in birds and reptiles. The discovery of blood cells in dinosaurs may help to solve the long-debated question of whether they were exothermic like other reptiles, or endothermic like mammals.

“In ten to fifteen years we might know a lot more about dinosaurs than we ever thought possible: information about physiology and what they looked like that we could never get from the bones alone. Our discovery has simply shown the potential for what might be preserved if we look in the right place,” Maidment says.


CATEGORIZED UNDER: Living World, top posts
MORE ABOUT: dinosaurs
  • John


  • James Scott

    What in the world is this supposed to mean?:

    “However researchers Sergio Bertazzo and Susie Maidment found that not only could these structures be preserved for 75 million years, but
    they could persist in run-of-the-mill museum collections that researchers wouldn’t normally glance twice at.”

    Okay, but where is the scientific explanation for how soft tissue and red blood cells can be preserved out in the wild for over 75 million years?

    The way that the scientific method works is that when scientists discover any empirical data that contradicts their theory or hypothesis, scientists become obliged to either throw out their theory or revise it, so that their theory conforms to the facts. They are not supposed to reinterpret the facts so that the facts conform to their theory. That would be a violation of the scientific method! And that is precisely what I detect here. Instead of drawing an inference to the best explanation which would be that these bones are not 75 million years old, they are absurdly claiming that it is somehow possible after all for soft tissue and red blood cells to be preserved in natural volatile conditions for over 75 million years. Give me a break.

    • nik

      Party pooper!

    • Llamaman

      the cells are preserved within bone (pretty much a sealed canister) and encased in rock sorry but what part of that is volatile conditions? and considering that the amount of time it takes to decay wasn’t previously known how could this new information contradict well established geological time? They didn’t know how long it could last before now they do. You’re just assuming that it should not take long to decay

      • dua

        Good that science makes no assumptions.

    • Jon Tennant

      James, thanks for your question. Susie and the other researchers are going to use this discovery of a basis to investigate your main question there!

      We don’t have facts. We have pieces of evidence that point towards a conclusion. If we find evidence to the contrary, we don’t throw it away, as you suggest. We investigate it in more depth, and change conclusions accordingly if need be. Try not to think of science as immobile facts, but very dynamic answers based on the best evidence we have – some things are supported more strongly than others, but as Susie said, never say never.

      Multiple independent lines of evidence showed that these are 75 million years old too, not new information presented in this study. And as Llamaman points out, these conditions aren’t “volatile” – by mineralisation of the soft tissues, we provide a mechanism for stable preservation through time. We’re only just beginning to understand how this can happen at this kind of scale, however.

      • Silver

        +El Coyote​​even under moderate scrutiny, Schweitzer’s explanation quickly falls to pieces. In her new paper she discusses experiments that appear totally unrepresentative of the conditions under which these dinosaur remains were actually preserved. Instead, she describes what boils down to a ‘best and worse case scenario’ for soft tissue preservation.

        “They soaked one group of (ostrich) blood vessels in iron-rich liquid made of red blood cells and another group in water. The blood vessels left in water turned into a disgusting mess within days. The blood vessels soaked in red blood cells remain recognizable after sitting at room temperature for two years.”
        Reading the supplementary material in her article it appears that pure hemoglobin was used, not lysed cells or materials that could be expected to mimic what would be present in an animal carcass. (Blood vessels soaked in laboratory-prepared hemoglobin is hardly representative of decomposing bones).

        One might also ask how realistic a concentrated hemoglobin extract is, compared to the real world. While unrealistically concentrated hemoglobin might preserve for a time, it doesn’t follow that natural, dilute hemoglobin will act the same way. Indeed, tissues rich in blood vessels, such as lungs and gills, often decay very quickly. One infamous example is the gills of dead basking sharks that rot and slough off to form the pseudo-plesiosaur shape.

        And the suggestion that blood vessels remaining ‘recognizable’ for two years somehow demonstrates that these could last thirty five million times as long requires a phenomenal cognitive leap.

        Further, it is not plausible that iron could be as good a preservative as formaldehyde, which directly forms covalent cross-links between protein chains, something iron can’t do

        Schweitzer’s idea is that iron generated free hydroxyl (.OH) radicals (called the Fenton Reaction) causing preservation of the proteins. But free radicals are far more likely to help degrade proteins and other organic matter. Indeed, the reaction is used to destroy organic compounds. It also requires that the hydroxyl radicals are transported by water. However, water would have caused hydrolysis of the peptide bonds, and very fast deamidation of the amino acids residues asparagine and glutamine. Aspartyl residue should also have isomerized to isoaspartyl residue if exposed to water. Tyrosine, methionine and histidine would have been oxidized under Schweitzer’s proposed conditions. But the dino proteins show show that these unstable residues are still present:

        The dilemma is this: how did the fragment successfully become cross-linked through aqueous hydroxyl free radical attack apparently explaining peptide survival while hydrolytically unstable moieties such as Asn avoid contact with the aqueous medium—for 68 million years? If we are to accept the benefits of random aqueous hydroxyl radicals cross-linking the peptide matrix in an undefined chemical bonding, we should also accept the cost—peptide and amino acid hydrolysis.

      • Tipsy

        Good answer, Jon.

    • Susie Maidment

      The rocks from which the fossils are found have been radiometrically dated and are well known to be about 75 million years old. That’s pretty much the least debatable thing about this.

  • Dan

    It means that dinosaurs did not go extinct 65 million years ago or nothing like this could be found under any conditions of preservation.

  • Dan

    The bone its self is radio carbon dated to less than 50000 years


      Are you aware that 50k years is near the upper limit of carbon dating? I hope you’re not suggesting that the bone is less than 50k years old.

      • http://www.picassodreams.com/ Kelly Ann Thomas

        How did they verify the bone was a dinosaur? They didn’t find a skeleton. Everything we know of dinosaurs is based upon artists’ renditions and speculation. No intact skeleton – or eve partial skeleton – has ever been found. It seems strange that the area was safely entombed to preserve a blood cell but there wasn’t evidence of a full skeleton in the area.

        if carbon dating is limited to 50,000 years, how does one verify it is 75 million years old? And with no other surrounding skeleton how does one verify that this is a dinosaur bone?

      • Dan

        less than 50,000 years… scientific method.

        • SAMUEL TUNES

          Lol, thanks.

    • Bon Bing

      That 50,000-year figure has been explained.

      From the National Center for Science Education.
      A sample that is more than fifty thousand years old shouldn’t have any measurable C-14. Coal, oil, and natural gas are supposed to be millions of years old; yet creationists say that some of them contain measurable amounts of C-14, enough to give them C-14 ages in the tens of thousands of years. How do you explain this?
      Very simply. Radiocarbon dating doesn’t work well on objects much older than twenty thousand years, because such objects have so little C-14 left that their beta radiation is swamped out by the background radiation of cosmic rays and potassium-40 [K-40] decay. Younger objects can easily be dated, because they still emit plenty of beta radiation, enough to be measured after the background radiation has been subtracted out of the total beta radiation. However, in either case, the background beta radiation has to be compensated for, and, in the older objects, the amount of C-14 they have left is less than the margin of error in measuring background radiation. As Hurley points out:

      “Without rather special developmental work, it is not generally practicable to measure ages in excess of about twenty thousand years, because the radioactivity of the carbon becomes so slight that it is difficult to get an accurate measurement above background radiation.”

      Cosmic rays form beta radiation all the time; this is the radiation that turns N-14 to C-14 in the first place. K-40 decay also forms plenty of beta radiation. Stearns, Carroll, and Clark point out that “. . . this isotope [K-40] accounts for a large part of the normal background radiation that can be detected on the earth’s surface”. This radiation cannot be totally eliminated from the laboratory, so one could probably get a “radiocarbon” date of fifty thousand years from a PURE CARBON-FREE piece of tin.

  • Dan

    Organics even as hard as bone, disintegrate spontaneously without living cells rebuilding, replacing and maintaining such tissue.

  • Theresa

    What was their blood type’s did they have positive blood and negative blood depending in the Dinosaur?

  • Dan

    bad science… sedimentary rocks are dated by assumed sedimentary rates, regardless of the fact that the asteroid buried the tertiary critters in less than a year through global tsunamis. Assuming the age of the rock, counter to C14 measurements is not good science. Let the facts lead instead of the assumptions.



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