New paper: Dolly, the dinosaur with a sauro-throat

February 10, 2022

I was at the SVP meeting in Albuquerque in 2018 when Cary Woodruff called me over and said he had something cool to show me. “Something cool” turned out to be photos of infected sauropod vertebrae from the Morrison Formation of Montana. Specifically, some gross, cauliflower-looking bony lesions bubbling up in the air spaces on the sides of the vertebrae.

Pathologic pneumatic tissue in MOR 7029. (A) Schematic map of the neck of Diplodocus (Hatcher 1901; bones not present in grey), with the pathologic structures denoted in red. (B) Cervical 5 of MOR 7029 with red box highlighting the pathologic structure; close up in (C) with interpretative drawing in (D) (by DCW) (pathology in red). Woodruff et al. (2022: fig. 1).

I was stoked, because I’ve been working on air-filled bones in sauropods since 1998, and in that time I’ve gotten countless versions of this question: “Do you ever see any evidence of respiratory infections in those air spaces?” For 20 years, the answer had been ‘no’, but now Cary was showing me a likely ‘yes’.

Better still, Cary asked me if I wanted to collaborate on writing up the case. He could have done it on his own, but right out of the gate he wanted to assemble a collaborative team. He also got paleopathologist and veterinarian Ewan Wolff, veterinary radiologist Sophie Dennison, and anatomist and paleontologist Larry Witmer. It was my first time collaborating with all of those folks, and it was really cool firing around ideas, observations, and references. Cary coined the clever title “Sauro-Throat” when we presented our preliminary results at SVP (Woodruff et al. 2020), and you’ll probably see it a lot in conjunction with this paper.

The elaborate and circuitous pulmonary complex of the sauropod, with the hypothetical route of infectious pathway in MOR 7029. Skeletal reconstruction of the diplodocine Galeamopus pabsti by and copyright of Francisco Bruñén Alfaro to scale with MOR 7029. Human scale bar is the exemplar of pandemic education and rationalism, Dr. Anthony Fauci, at his natural height of 170 cm. Woodruff et al. (2022: fig. 3).

A little over three years after our meet-up in Albuquerque, one global pandemic notwithstanding, our results are out this morning in Scientific Reports (Woodruff et al. 2022). Normally I’d write a mini-dissertation about our findings, but I decided to do a little video explainer instead. That’s the video linked up top — many thanks to Fiona Taylor (music), Brian Engh (paleoart), and Jennifer Adams (filming and editing) for the timely help in getting it done.

I’ll have more to say about this in the future. For now, the paper is a free download at this link. Go have fun!

UPDATE later the same day:

Woo-hoo! Dolly is the top science story on Google News:

Google News UK:

The Guardian — with fabulous quotes by Steve Brusatte and, especially, Mike Benton:

…and probably others, but that’s enough navel-gazing for one afternoon.

References

25 Responses to “New paper: Dolly, the dinosaur with a sauro-throat”

  1. Brad Lichtenstein Says:

    So, Fauci – did you guys prove it was a coronavirus? Sauropod Immunodeficiency Virus?

    And maybe the dumb Q – how often do respiratory infections show up in bone tissue? I had assumed until now they were exclusively in soft tissue. Nearby inflammation stimulates bone growth?

    Either way, bravo!

  2. Mike Taylor Says:

    It’s worth highlighting this, from the acknowledgements:

    The entire research team would also like to dedicate this work to the memory of Dr. Vicki Wedel — a phenomenal scientist, a courageous advocate for rights, privileges, and equality in science, a devoted educator, a caring and supportive mentor, a loving mother, and the best of partners.

    Well merited!

  3. Matt Wedel Says:

    Brad wrote:

    did you guys prove it was a coronavirus?

    Nothing so specific. We’re just happy to be able to present solid evidence of airsacculitis in a non-avian dinosaur.

    how often do respiratory infections show up in bone tissue?

    Not often. Or rather, not often in a diagnostic sense. We’re up against what’s called the Paleopathological Paradox: if a disease is too serious, it kills an animal too quickly to manifest in the skeleton, and if it’s not serious, the animal recovers. In either of those cases, there will be no skeletal evidence of the disease. All we get in the fossil record (and the archaeological record!) is the narrow set of diseases that were serious enough to leave traces in the skeleton, but survivable enough that the host could live long enough for that to happen. That’s a pretty narrow needle to thread.

    We know from birds that infectious crap gets into the air sacs all the time. It’s one reason that dust control is such a big concern on poultry farms. But respiratory infections usually kill birds too quickly to leave any skeletal traces. When they do persist for a long time, they can produce reactive bone lesions like the ones we see in Dolly.

    Also, thanks for the kind words!

    The dedication was Cary’s idea, and a really beautiful one. That’s a good dude right there.

  4. Jura Says:

    I love the addition of the video summary.I think these always make for useful additions / dissemination methods for papers. My only quibble is in the resolution. Any chance we can get it higher than 360p?

  5. Matt Wedel Says:

    I’ll see what I can do. Thanks for the kind words!


  6. This is awesome. What a wonderful find!

  7. llewelly Says:

    A great paper, though very sad for Dolly.

    A question:

    Birds, as far as I know, seem to grow very quickly to adult size, and then stop at adult size and stay there for the rest of their lives.

    Sauropods, as far as I know, grew rapidly for a much longer portion of their lives, relative to the whole length of their lives. Does this longer period of growth make it more likely that a respiratory infection would affect the bones enough to be preserved?

  8. Matt Wedel Says:

    llewelly, that is a great question, that opens up a lot of ideas in my mind. I wrote a few paragraphs of response before I realized that the answer needs to be its own post.

    BUT before I go there, I want to make sure I don’t misunderstand or misrepresent your question. If I’m following you, I think you’re suggesting (and correct me if I’m wrong) that (1) the vastly longer developmental time of sauropods would give them more opportunities to ‘capture’ evidence of a respiratory infection in the skeleton. And maybe also implying that (2) the bone/air-sac interface of actively-developing sauropod vertebrae might be a better capture mechanism than the essentially finished bone/air-sac interface of bird vertebrae, which as you point out develop very quickly, both in absolute time and as a fraction of the animal’s life span (or, if you’re not implying that, it’s something people might be curious about, so I’m probably going to yap about it).

    Are either of those accurate, or did you have something else in mind, that I haven’t thought of?

    Also, thanks for the kind words!

  9. llewelly Says:

    I was mainly thinking about question (1): would the longer developmental time of saurpods give more opportunities to capture evidence of respiratory infection?

    I did think about (2) a little but then I ran into an issue; I don’t know if growing bone would respond differently to such an infection, when compared to bone that is finished growing, or what those differences might be.

  10. Matt Wedel Says:

    Okay, excellent. I have plenty to say on both points, I just don’t have time this morning to get all that done (exam questions are due and I have lectures to record) — but there will be a post about these things along soon. And to be clear, these are excellent questions, and I’m excited to have the chance to think about them and discuss them.


  11. […] to create 3D models, which are now viewable on Sketchfab. (See the announcement post about Dolly here, and our open-access paper on her pathological vertebrae […]


  12. […] working on Dolly, the diplodocid with lesions in its neck vertebrae (see previous posts on Dolly here and here). I was also intellectually excited, not only to see air-filled bones with obvious […]


  13. […] closed the last post by claiming that finding the infected bone in Dolly was “a crazy lucky break”. Here’s […]

  14. Matt Wedel Says:

    Well, almost two weeks later I have very belatedly realized that I am not going to get a separate post done, in part because I am so unsure about my answers. So I’m going to do what I should have done a long time ago, and post what I have (in response to llewelly’s questions up-thread):

    The short answers are ‘maybe’ and ‘probably not’, respectively.

    For (1), there are a few factors to consider, including longevity, robustness, and potential to heal.

    Longevity: Wild birds can be surprisingly long-lived, with even small-bodied species like sparrows and hummingbirds making it to roughly a decade, and hawks, swans, herons, and pelicans going to a quarter century. Obviously those are records, not averages, and most individuals die a lot younger — but then sauropods, with their sea-turtle-like breeding strategy, must have suffered appalling levels of egg and hatchling mortality.

    I have little doubt that fully adult sauropods lived longer on average than fully adult birds, but given that the sauropod fossil record is dominated by subadults, it’s not super-obvious that the average sauropod lived longer than the average bird, even if we ignore the probably insane level of hatchling mortality in sauropods. Or at least we might be talking about the average sauropod (across all sizes and lineages) only out-living the average bird (across all sizes and lineages) by something like a factor of 2 or 3, and not a factor of 10.

    Robustness: here I think sauropods probably do get the upper hand. I haven’t been able to find much on this, and if someone has some actual data I’d be very interested to see it, but my guess is that bigger animals are in general less fragile and have larger reserves of energy for fighting off infections. Also, for most birds the ability to fly is intimately linked to survival, so there is probably a threshold effect where any disease process that even temporarily interrupts the ability to fly is more likely to be lethal — and remember, a disease process that kills an animal quickly (in days or weeks instead of months or years) is less likely to leave skeletal traces. The upshot is that if sauropods were more likely to survive infections, because they were physically larger, could go without eating longer, or didn’t have a flight-related lethality threshold, then they’d be more likely to live long enough for diseases to manifest in their skeletons.

    Potential to heal: I don’t know how much we know, or can possibly know, about the immune systems of non-avian dinosaurs, but extant reptiles can survive pretty horrifying infections and injuries, which would kill most mammals. But I don’t know if sauropods were any better at healing from groady infections than birds are — this overlaps a bit with the last point. But IF sauropods were more likely to survive infections than birds, then they might also have been more likely to live long enough to fully recover, and for their bones to remodel away all of the skeletal evidence of the infection.

    As for the second question — whether a still-developing pneumatic bone in a sauropod would be a better pathology capture mechanism than the ‘finished’, fully-pneumatized bone of an adult bird: I doubt it. All available evidence says that pneumatic bones are getting remodeled all the time, regardless of the age of the individual. So I’d think that the potential for a bony lesion to be completely remodeled away during the healing process would be high in both birds and sauropods. That said, the fact that pneumatic cavities are so open in most sauropods might make vertebral lesions easier to see — and therefore to discover — than in birds. Plus, essentially every sauropod vertebra that gets found gets looked at, at least cursorily, and Dolly-type lesions are eye-grabbers. Most diseased birds never get skeletonized, let alone combed over by someone looking for pathologies. So sampling biases might tilt things toward sauropods, despite the horrendous difference in numbers.

  15. Brad Lichtenstein Says:

    I may I asked this before, apologies if I forgot an answer – given sauropod “strategy”, iirc, was, more or less, to turn on maximal growth rate as soon as hatched (in contrast to, say, T. rex, and assuming sufficient food), and somewhere you wrote about how sauropods effectively extended their babyhood to maintain that growth rate until they got huge – did they (or at least some species) ever STOP growing?

    I mean, humans turn on sexual reproduction prior to stopping growth, so the latter isn’t a prereq for the former. It seems plausible that the oldest, and therefore largest, sauropods simply broke under the weight after getting too large, the way modern for-meat chickens will soon quickly outgrow their ability to stay upright and/or skeletally intact (they’ve been bred for rapid growth, and it’s possible the phylogenetic mechanism may be to just not stop growing, or to “always-on” maximal growth – I have no idea. They may also only overdevelop their breast meat is maybe why they eventually lose balance if not slaughtered soon enough – my brother raised a few hundreds of them quasi-free-range a couple decades ago, and he often didn’t get them killed quickly enough because his main focus was the dairy – I don’t recall the full spectrum of what he said was the results of that). But I don’t know what you mean by “most sauropod specimens are sub-adult – that would simply imply to me that, just as few survive egg/hatchling to become what I’d assume is sub-adult, and few of those survivors make it to sexual reproduction age which I would assume is adult, and fewer of those survive to old age. Lol, but I’m on the outside looking in…

  16. Matt Wedel Says:

    did they (or at least some species) ever STOP growing?

    Given that effectively all animals reach asymptotic growth at some point, stopping would be the null hypothesis for sauropods. And we have individuals with external fundamental systems and other histological indications of senescence. Admittedly not the very largest individuals, usually, but ever-growing sauropods would be a stretch.

    But I don’t know what you mean by “most sauropod specimens are sub-adult”

    I realize now that was unclear. But both of the things that I might have meant are true. First, most mounted sauropod skeletons in museums are from individuals that were not skeletally mature (they have joints unfused, they aren’t the largest known individuals of their respective taxa, etc. — this has been discussed a LOT here on the blog over the years, see especially the posts related to Farke et al. 2016). Second, most sauropod specimens anywhere, on display or in collections, are also from individuals that were not skeletally mature. In fact, the specimens in collections are much less mature on average than the mounted skeletons, since they include so many smaller and therefore less impressive individuals. Anyway, the filter you describe in your penultimate sentence, with just a fraction of individuals making it through each growth stage to the next, was probably real.

  17. Brad Lichtenstein Says:

    If the survival strategy is “grow big”, then a logical conclusion would be, “grow big over your whole lifespan” – whether or not any species ever took that conclusion. But if some of the largest specimens are NOT skeletally mature, then that would seem to point that direction for those species. The only other group of animals that seem plausible for that strategy, would be water dwellers – but almost all large water animals I’ve ever heard of, have been carnivores, which might limit their ultimate size more than an herbivore, tho blue whales are BIG. But they stop growing, was my understanding. Shrug. Whatever sauropods did, they did. Obviously it would be nice to pull a Jurassic park and study them live.

  18. Matt Wedel Says:

    It’s not enough to have a survival strategy, it’s also necessary to have a reproduction strategy. In particular, size and reproduction pull in different directions. See this post and its comment thread.

  19. Mike Taylor Says:

    “Extant reptiles can survive pretty horrifying infections and injuries, which would kill most mammals.”

    And yet, at the same time, pet reptiles have a bad habit of suddenly dropping dead for no obvious reason. I wonder what’s going on there?

  20. Mike Taylor Says:

    Brad:

    “Humans turn on sexual reproduction prior to stopping growth […] Modern for-meat chickens will soon quickly outgrow their ability to stay upright and/or skeletally intact.”

    All true, but I would always be hesitant to generalise anything from either of those species. The chickens are obviously the endpoint of the most extreme an unhealthy artificial selection, but humans are crazy, too — so weird in so many ways. I often think about Chesterton’s theological observation as a purely biological one:

    Man is an exception, whatever else he is. If it is not true that a divine being fell, then we can only say that one of the animals went entirely off its head.

  21. llewelly Says:

    Thank you, Matt, for all the time you spent on these questions. I feel like I’ve learned a lot, but I don’t (yet) have much to say about it.

  22. Matt Wedel Says:

    You’re welcome! It’s nice to have engaged commenters. Basically, Mike and I like to talk about sauropods to a possibly pathological degree, and this blog enables our dysfunction.

  23. Brad Lichtenstein Says:

    “Hello, Matt.” Lol, and thanks to everyone for sharing your time and expertise here! Apologies for when my noob Q’s/remarks are frustrating to anyone else here. I frustrate me, too, at times.

  24. Jura Says:

    “And yet, at the same time, pet reptiles have a bad habit of suddenly dropping dead for no obvious reason. I wonder what’s going on there?”

    Reptiles are also really good at hiding when they are sick and malnourished, making it easier for a preventable problem to go untreated to the point of no return. Add in the fact that pets are beholden to the whims (and observations) of their owners (making it hard for the animals to adjust on their own), plus our relative dearth of knowledge on reptile physiology and you wind up with a lot of premature deaths among pet reptiles.

    Having said all that, herpetoculture has gotten a lot better over the past thirty years.


  25. […] to be an author on, including the saltasaur pneumaticity paper (Aureliano et al. 2021) and the ‘Sauro-Throat’ paper (Woodruff et al. […]


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