This Saturday is Aquilops Day!
July 17, 2025
This Saturday, July 19, the Sam Noble Oklahoma Museum of Natural History is hosting Aquilops Day.
Before Jurassic World Rebirth was released, I was interviewed by the folks at the SNOMNH about Aquilops. Andy Farke and I got quoted a few places (here, here, and here). I was really happy to see Scott Madsen get some attention (here) — if he hadn’t found and prepped the fossil, Aquilops wouldn’t be a thing, and we’d know a lot less about the earliest ceratopsians in North America.
It was nice to see that one quote of mine get around, but the rest of the interview was just sitting in email, so I got permission from the SNOMNH folks to post it here.
When the specimen was first discovered in the field what did the team think it was initially? Were they looking for anything specific in the area?
I wasn’t on the expedition in the summer of 1997 when Scott Madsen discovered the Aquilops type specimen — everything I know about this I learned from Scott and from Dr. Cifelli later. I did go out to the Cloverly Formation with the OMNH crew in the summer of 1998. To answer those questions in reverse order: even in 1998 we were looking for anything and everything. I did a lot of prospecting that summer with Scott and the rest of the crew, just walking outcrops for hours in hopes of finding either fossil skeletons or a promising microsite, someplace that preserved a lot of tiny bones and especially teeth that we could retrieve by screenwashing the sediment. Dr. Cifelli had been very successful getting tiny teeth of early mammals, lizards, snakes, and more from microsites in the Cedar Mountain Formation in Utah and, to a lesser extent, from the Antlers Formation in southeast Oklahoma, and we were hoping to replicate that success in the Cloverly. But we also were not going to turn down larger fossils like skulls and skeletons.
According to Scott’s account of the discovery (link), everyone initially assumed it was a Zephyrosaurus, a small plant-eating dinosaur distantly related to duckbills. It was only during the process of preparing the skull out of the surrounding rock that Scott found the beak and realized that it was an early horned dinosaur — the earliest anywhere in the world outside of Asia.
Table centerpiece at my birthday party last month.
It’s more rare or unusual to find a dinosaur’s skull relatively intact isn’t it? Do we know or can we guess what circumstances caused this specimen’s skull to be preserved without the rest of its body?
It does often seem like feast or famine with dinosaur skulls. There are numerous dinosaurs for which we have most of the skeleton but no skull, and some others for which we have a skull but nothing else. For relatively large-headed animals like Aquilops, the skull and the body are basically two big masses connected by a weaker linkage — the neck. It’s common for the head to become separated from the body after death, as the carcass is moved around by scavengers or simply by flowing water. The same thing happens to human bodies in forensic situations.
My better half, Jenny Adams, with a plush Aquilops.
What adaptations did Aquilops and other early ceratopsians have that made it so successful? What environmental pressures caused such a small, unassuming dinosaur to eventually evolve into some of the largest land animals that ever lived?
Ceratopsians had nifty teeth that could efficiently cut up plants, like walking around with paired sets of garden shears in their mouths. And to power those shears, they had enlarged attachments for jaw muscles at the backs of their skulls, which were the first beginnings of the frills that things like Triceratops and Pentaceratops would take to such flamboyant lengths later on. But even the little cat- and pig-sized ceratopsians were pretty successful, based on the high diversity of early ceratopsians in China and Mongolia — the ancestors and cousins of Aquilops.
The combination of big jaw muscles, shearing teeth, sharp beak, and pointy skull bits worked well across a wide range of body sizes, from little tiny things like Aquilops to the later rhino- and elephant-sized horned dinosaurs. I think it’s particularly interesting that even in the Late Cretaceous, generally Aquilops-like small ceratopsians such as Leptoceratops were still thriving alongside giants like Triceratops. So it’s not the case that big ceratopsians replaced small ceratopsians, rather that the range of successful body plans expanded to include big multi-horned four-leggers. But the little ones were still doing fine, more than 40 million years after Aquilops existed.
My Aquilops t-shirt was a birthday present from Andy Farke. I didn’t even know the other one existed until Jenny got it delivered.
How accurate do you think Aquilops’ representation will be on the big screen? What would be the biggest challenge in realistically portraying Aquilops in film — locomotion, coloration or something else?
We have a lot of advantages when it comes to reconstructing the little early ceratopsians. From Asia we have multiple complete skeletons of close relatives of Aquilops, like Psittacosaurus, and some of those have fossilized impressions of the skin, including scales, color patterns, even protofeathers or “dinofuzz”. So we can reconstruct those animals with a lot more certainty than we can most of larger and more famous dinosaurs like Spinosaurus or Dilophosaurus. There isn’t a single Dilophosaurus in the world in which the tippy-top of the skull is intact, so we still don’t know the full shape and extent of the head crest (more on that here).
From the footage I’ve seen in the trailers, I think the moviemakers did a pretty darned good job with Aquilops. The body proportions look good, the colors and movements are plausible, nothing set off any red flags for me. I do wonder about disposition. A lot of small plant-eaters today are pretty skittish, and they can fight aggressively when cornered — think about the attitude of a bantam rooster, or an angry goose. My guess is that a live Aquilops would be so good at hiding that humans moving through its environment would never even see it. But for the sake of getting to see “my” dinosaur on the big screen, I’m glad the moviemakers went another way.
If this is wrong, I don’t want to be right.
One more question for fun… if you were consulted about creating this dinosaur’s on-screen persona, what kind of personality do you think it would or should have had? Nervous? Intelligent? Are there any modern animals that might have a similar personality?
When Dr. Farke, who was the lead author on the Aquilops project, and I were coordinating with Brian Engh, who did all of the art for the paper and the press release, we wanted to show a person holding an Aquilops to give a sense of scale. One of the things we talked about is that living animals with beaks or sharp teeth have a tendency to bite when they feel threatened. The core ceratopsian superpower was having very powerful jaw muscles pushing scissor-like teeth and a wickedly sharp beak. One of Brian’s preliminary sketches showed an Aquilops jumping out of a person’s arms and nipping their fingers on the way. As much as I love the idea of an adorable, friendly “cat-ceratops”, I think a real-life Aquilops would have no problem kicking, scratching, and especially biting if it got cornered by a human. Imagine a raccoon with the head of a snapping turtle — would you want that in your backpack?
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One thing occurred to me after the interview, and after I saw the movie: the filmmakers may have gotten Dolores’s personality more correct than I thought. In the movie, the island had been uninhabited by people for 17years, and presumably Dolores is younger than that. She’d have no reason to fear people, and given the wiiiide variation in animal personalities, it wouldn’t surprise me if some Aquilops were more inquisitive than skittish. I still don’t think I’d want a cat-sized biting machine in my backpack; as Xavier says in the movie, “That may or may not be a terrible idea.”
So anyway, if you’re in or near central Oklahoma this weekend, you could do a lot worse than swinging by the Sam Noble Museum to enjoy Aquilops Day. I myself am planning on giving a short virtual presentation there — watch this space for more. EDIT: my talk, “Bringing Aquilops to Life”, will run from 1:00-1:15 PM, Central Daylight Time.
And since I’ve linked to more than one YouTube video already in this post, go watch Gabriel Santos’s awesome short on Aquilops — it’s good for you.
Five questions from Tom Redd
October 24, 2024
Three years ago, Tom Redd made a very generous commitment to the SV-POW! Patreon, and he remains our most generous donor in total. When I wrote to thank him his reply included “I have thousands of questions about apatosaurus that I would like to ask you some day.”
It seemed only fair to invite him to ask some of those questions, so we asked him to give us five and said we’d try to answer them. When the questions came through, some of them were hard — not really in our area of expertise. But I promised we’d take a crack, and that we’d invite commenters to chip in where we get something wrong or leave something out.
Then a bit more than three years slipped past. Now, finally: here we go!
Question #1:
Do you think sauropods could have evolved long necks as a defensive strategy? (Better to see your enemies from a long way off). The sigmoid curve and the neutral position is another issue!
I recently read a couple of research papers where the researcher used “radiological imaging” to determine the neutral position of the cervical vertebrae. The result was a gently downward curving neck beginning at the pectoral girdle, with the skull only 2 meters off the ground. (I agree with Matt that this would be an ambush predator’s delight!)
Also, could compressive or tensional forces of cartilage and ligaments affect the neutral position of the cervical vertebra? (I believe Matt also alluded to this condition.)
This is the longest question, but maybe the one I’m best positioned to comment on.
First of all, the perennial question of what sauropods’ long necks were for. There are a few candidate explanations out there. The obvious one is that they enabled high browsing, and on the whole we feel that’s the strongest single explanation. Another candidate factor is sexual selection — that sauropods were particularly attracted to long-necked individuals of the opposite sex — but we don’t feel that is a strong explanation for reasons explained in our 2011 paper (Taylor et al. 2011). Predator avoidance would certainly have been aided by the long visual distances allowed by elevated heads, and we are confident that at least some sauropods used their necks in combat — primarily in intraspecific combat (Taylor 2015) but no doubt also against predators when the occasion arose. And we may well have missed other good uses for long necks.
In reality of course all these factors likely played a role: structures do not always, or even often, evolve for a single reason. When people who know much more about ceratopsians tell me “The horns of Triceratops were for intraspecific display and combat”, I don’t doubt them. But I also don’t doubt that, whatever the primary purpose of the horns, a Triceratops confronted by a Tyrannosaurus would do its damnedest to stick its horns into it. In the same way, while high feeding seems like the strongest driver of sauropod neck elongation, the other factors will surely have played in, too.
I’m not sure what radiological imaging papers you have come across, but the one I know about is Berman and Rothschild (2005) in the Thunder Lizards edited volume. This paper rather questionably partitions all sauropod cervicals into two bins, “robust” and “gracile”, and concludes, based on functional stress analysis, that “the robust-type centrum supported a neck held in a vertical, or near-vertical, pose, whereas the gracile-type centrum supported a neck held in a horizontal, or near-horizontal, pose”. If this is right, and their categorization holds, then Camarasaurus and an unidentified titanosaur had vertical necks; and Diplodocus, Apatosaurus, Haplocanthosaurus, Barosaurus and Brachiosaurus all had horizontal necks. We find every part of this unconvincing. At some point we should explain why in detail; but it is not this day.
Finally, yes, compressive and tensile forces in cartilage and ligaments definitely did affect neutral posture. My 2014 paper (Taylor 2014) shows this rather dramatically.
What we’re seeing here is what the neutral posture would be if cartilage is added to a neck that is otherwise articulated in horizonzal pose. The importance of intervertebral cartilage has often been overlooked, but can make a dramatic difference to neck posture.
Question #2
I recently read a report that indicated Apatosaurus survived at the species level for a period of approximately 8 million years ! So is this a success, average, or a short run?
I’m not sure where you read that, but the problem here is that no-one really knows what Apatosaurus means. We have the type species Apatosaurus ajax, sure, and the referred species Apatosaurus louisae, and the genus Brontosaurus based on the species Brontosaurus excelsus which is sometimes but not always synonymised with the genus Apatosaurus yielding the combination Apatosaurus excelsus, and don’t even get me started on Apatosaurus parvus, Apatosaurus laticollis, Atlantosaurus and whatever the heck AMNH 460 is.
So if we say that Apatosaurus survived for 8 million years, what exactly are we saying? That Apatosaurus ajax is known from sediments that differ in age by 8 million years? That would be interesting if true, but it’s very hard to establish because the referral of any given individual to a particular sauropod species tends to be very uncertain — largely because most specimen are so fragmentary and distorted. And if all we mean is that 8 million years separate the oldest and youngest specimens that have been referred to the genus Apatosaurus — well, that statement is all but meaningless, given the huge uncertainty about what is and is not part of that genus, if indeed genera even really mean anything.
Putting it all together, I’m not confident that there is any reason to think that Apatosaurus was particularly longer lived than other sauropods. Probably Camarasaurus outlasted it if you include all the taxa that have been referred to Camarasaurus. But then I’m far from convinced that that’s the right thing to do, too.
Question #3
Why so many heavy predators during the age of apatosaurs? Predator to prey ratios were in the 6 to 8% range as compared to modern ratios of 2 to 3%!
I’m not sure I can say much about this without knowing the source of the figures, but I assume that what’s being counted here is the number of individuals represented in the fossil record, and the ratio of a predator species to prey species. The problem is that there is a huge amount of vagueness in these numbers, but it’s not obvious that the apatosaur-age figures are comparable to the modern ones.
Consider first the modern ratio. Which animals are counted in each category? In the Serengeti, lions prey on zebras. So far, so simple, but there are also dwarf moongooses, which are predators — but they don’t hunt zebras. So do we count them in the numbers? If so, do we count their prey animals, too? Including invertebrates? And if not, then where do we draw the line between predators that we consider do and do not hunt the prey animals that we’ve decided we’re interested in?
Then there’s the matter of which animals get counted. If you do your Serengeti counts on dead animals, you might find disproportionately many predators because prey animals tend to be consumed. Or you might find disproportionately many prey animals because they tend to die in areas where the corpses are more easily found and counted. You might be able to do better by counting live animals, but then you might easily undercount secretive predators, or perhaps overcount predators because they stand fearlessly around to be counted.
Now consider trying to measure the predator/prey ratio in the Morrison formation. You have all the problems I already mentioned, plus a bunch of others. If you only count complete-ish articulated skeletons then your sample size is too small to be meaningful. If you count isolated elements, you’re at risk of registering multiple instances of the same individual. Counting individuals represented in bonebeds is difficult because of these problems. Assigning an element to a taxon is error-prone (though should generally be OK at the high level of sauropod vs. theropod — or are you?). Bones of different taxa may survive taphonomy better or worse than others. Life history differences will mean that the fossils of long-lived taxa under-represent their live populations. And so on, and on, and on.
Putting it all together, I would tend to be very sceptical that a difference in ratios of 6–8% to 2–3% is necessarily telling us anything.
With all that said, it’s perfectly possible that the average predator:prey body-size ratio was closer in the Morrison than in modern ecosystems. But we’d do better trying to measure that directly from body-fossils than to infer it from population densities.
Question #4
Are all apatosaur tracks on emergent surfaces? (Some depth of water over the prints)
This I don’t know. But then I wouldn’t know how to pick out apatosaur tracks from those of other diplodocids, and I bet no-one else does, either. Tracks are notoriously variable in shape, and can very wildly from the that of the feet that made them. Given that diplodocid feet were mostly pretty similar anyway, I would not be easily persuaded that any track can be confidently identified down to the genus level.
One other thing to be aware of is that there is often not agreement on the conditions under which a given track is made. One palaeontologist may think a given a track is a direct print, another will think it’s an underprint. I don’t mean to say that it’s hopeless and all we can do is throw our hands up in despair — good work is being done on interpreting tracks, but we have a long way to go. And this is not an area that I’m at all expert in.
Question #5
I read recently that in order for a skin impression to be made the Dermal tissue must undergo a type of chemical alteration! Do you think this is what allows the impression to be made?
That doesn’t sound right to me. The first thing that has to happen for an animal to be fossilized is that it needs to be buried in sediment really fast after it dies — before it’s eaten by scavengers. For something as fine as skin impressions to be preserved, that sediment needs to be very fine — which sadly tends to conflict with the first condition, since course sediments can be deposited more quickly than fine ones. It’s really hard for enough fine sediment to be laid down quickly enough to cover an animal of the size of a sauropod, which is why we don’t have sauropod specimens like those gloriously preserved theropods from the Yixian Formation in China(*). So sauropod skin impressions are pretty rare.
(*) Alternatively: there are spectacularly preserved partial sauropod specimens in the Yixian, but Chinese researchers can’t be bothered to write them up because they’d rather spend their time getting a slam-dunk Nature paper out of yet another little feathered theropod. Unduly cynical? Maybe. But I continue to live in hope.
Well, that about wraps up the five questions — to the best of my ability at least. But I’d love to hear from people who know more than I about these topics: leave a comment, and fame and glory could be yours!
And finally … if you, too, would like to have us answer five questions on the sauropod-related topic of your choice, quite possibly in the less than three years, you should consider getting yourself across the The SV-POW! Patreon and making an unreasonably extravagant financial commitment.
References
- Berman David S., and Bruce M. Rothschild. 2005. Neck posture of sauropods determined using radiological imaging to reveal three-dimensional structure of cervical vertebrae. pp. 233–247 in: Virgina Tidwell and Ken Carpenter, Thunder-lizards: the sauropodomorph dinosaurs. Bloomington: Indiana University Press.
- Taylor, Michael P. 2014. Quantifying the effect of intervertebral cartilage on neutral posture in the necks of sauropod dinosaurs. PeerJ 2:e712. doi: 10.7717/peerj.712
- Taylor, Michael P., David W. E. Hone, Mathew J. Wedel and Darren Naish. 2011. The long necks of sauropods did not evolve primarily through sexual selection. Journal of Zoology 285:150-161. doi: 10.1111/j.1469-7998.2011.00824.x
- Taylor, Michael P., Mathew J. Wedel, Darren Naish and Brian Engh. 2015. Were the necks of Apatosaurus and Brontosaurus adapted for combat?. p. 71 in Mark Young (ed.), Abstracts, 63rd Symposium for Vertebrate Palaeontology and Comparative Anatomy, Southampton. 115 pp.
Sauropod Vertebra Picture of the Week 