In praise of Jack McIntosh
December 14, 2015
A short one today, and a sad one.
I heard last night on Twitter that Jack McIntosh has died at the age of 92. It would be hard to overstate what an inspiration he’s been to me. As a professional in a non-palaeo field who went on to do crucial work in sauropod palaeontology, he blazed a trail that I have tried in my small way to follow. I think it’s true to say that, without his example, I would never have got into palaeo research — never even considered it a possibility.
Jack McIntosh, still going strong at a conference late in life. Picture from this tweet by ReBecca Hunt-Foster. Hans-Dieter Sues for scale.
Others have written more about McIntosh’s crucial work — for example, determining the correct skull skull for Apatosaurus (McIntosh and Berman 1975), his careful historical work in collections (McIntosh 1981), his detailed monographic descriptions (e.g. McIntosh et al. 1996) and most recently his re-evaluation of Barosaurus (McIntosh 2005). When I made my own start in palaeo, around 2000, his chapter in The Dinosauria (McIntosh 1990) was the definitive overview of the sauropods.
Perhaps the best overview of his life and work is the interview that Jeff Wilson and Kristi Curry Rogers conducted with him for the afterword of the volume that they edited in his honour in 2005 (Wilson and Curry Rogers 2005). It’s well worth reading.
Pittsburgh, Pennsylvania, USA — Leading sauropod expert Jack McIntosh beneath Apatosaurus Louisae at the Carnegie Museum of Natural History, a forty-ton vegetarian named after Andrew Carnegie’s wife, which is over seventy-seven feet (over 23 meters) long and is the longest mounted dinosaur in the world. — Image by © Louie Psihoyos/Corbis
I’ll close with my own brief experience of meeting Jack, a privilege that I had only once. It was the 2007 SVP meeting in Austin, Texas. I somehow got invited to a sauropod workers’ lunch one day. By careful manoeuvring, I managed to sit myself next to Jack. At that stage I had two very minor papers to my name — the 2005 note on the phylogenetic taxonomy of diplodocoids and the 2006 Mesozoic Terrestrial Ecosystems short-paper on dinosaur diversity. In short, I was a nobody.
But Jack was fascinated by what I was working on. At that time, the Xenoposeidon paper was in press — no-one had seen it but Darren (my co-author), the handling editor and three peer-reviewers. I sketched the holotype dorsal vertebra — literally on a napkin, if I remember rightly — and explained all the unique features. At this point, Jack was 84 years old and could certainly have been forgiven for just wanting to have his lunch in peace, but he was deeply interested. Even at the time I was aware of the honour of showing this work to a man who’d been at the forefront of my field for four decades.
I don’t remember whether we discussed it at the time, but I’d spent the previous week, with Matt, Randy Irmis and Sarah Werning, in the collections at the Sam Noble Oklahoma Museum of Natural History, working on the remains of a sauropod from the Hotel Mesa quarry in the Cedar Mountain Formation. When the paper finally came out four years later (Taylor, Wedel and Cifelli 2007), we named the new dinosaur Brontomerus mcintoshi in Jack’s honour. Very nearly but not quite a year earlier, Chure et al. (2010) had beat us to the punch by naming their brachiosaurid Abydosaurus mcintoshi after him.
To the best of my knowledge, that makes Jack the only person in history to have had two sauropods named after him in a year. A fitting tribute indeed.
Update 1 (16 December)
Ken Carpenter writes: “Mike, Here is the electronic card I made for McIntosh’s 90th birthday. I’d like to have posted at SVPoW.”
Update 2 (16 December)
Jeff Wilson has written a piece that goes into much more detail about McIntosh’s scientific achievements. Well worth a read.
References
- Chure, Daniel, Brooks B. Britt, John A. Whitlock and Jeffrey A. Wilson. 2010. First complete sauropod dinosaur skull from the Cretaceous of the Americas and the evolution of sauropod dentition. Naturwissenschaften 97(4):379-91. doi:10.1007/s00114-010-0650-6
- McIntosh, John S. 1981. Annotated catalogue of the dinosaurs (Reptilia, Archosauria) in the collections of Carnegie Museum of Natural History. Bulletin of the Carnegie Museum 18:1-67.
- McIntosh, John S. 2005. The Genus Barosaurus Marsh (Sauropoda, Diplodocidae). pp. 38-77 in Virginia Tidwell and Ken Carpenter (eds.), Thunder Lizards: the Sauropodomorph Dinosaurs. Indiana University Press, Bloomington, Indiana. 495 pp.
- McIntosh, John S. 1990. Sauropoda. pp. 345-401 in: D. B. Weishampel, P. Dodson and H. Osmólska (eds.), The Dinosauria. University of California Press, Berkeley and Los Angeles.
- McIntosh, John S., and David, S. Berman. 1975. Description of the palate and lower jaw of the sauropod dinosaur Diplodocus (Reptilia: Saurischia) with remarks on the nature of the skull of Apatosaurus. Journal of Paleontology 49(1):187-199.
- McIntosh, John S., Wade E. Miller, Kenneth L. Stadtman and David D. Gillette. 1996. The osteology of Camarasaurus lewisi (Jensen, 1988). BYU Geolgy Studies 41:73-115.
- Taylor, Michael P., Mathew J. Wedel and Richard L. Cifelli. 2011. A new sauropod dinosaur from the Lower Cretaceous Cedar Mountain Formation, Utah, USA. Acta Palaeontologica Polonica 56(1):75-98. doi: 10.4202/app.2010.0073
- Wilson, Jeffrey A., and Kristina A. Curry Rogers. 2005. A conversation with Jack McIntosh. pp. 327-333 in: Kristina A. Curry Rogers and Jeffrey A. Wilson (eds.), The Sauropods: Evolution and Paleobiology, University of California Press, Berkeley, Los Angeles and London. 349 pages.
Well, who knew? There I was posting images of “Pelorosaurus” becklesi‘s humerus, radius and ulna, and skin impression. There I was saying that this beast is due a proper description, and warrants its own generic name. And what should come out today but a new paper by Paul Upchurch, Phil Mannion and, oh yes, me, which does exactly that.
The headline news is the long-overdue establishment of a new genus name for this species — something that we’ve known was needed at least since Upchurch’s (1993) dissertation. Paul and Phil came up with the name Haestasaurus, from “Haesta”, the name of the putative pre-Roman chieftain whose people apparently settled the area of Hastings and gave the town its name. It’s nice that I can finally stop typing the scare-quotes around the no-longer-relevant old genus name “Pelorosaurus“!
Upchurch et al. (2015: figure 2). Left humerus of Haestasaurus becklesii (NHMUK R1870). A, anterior view; B, posterior view; Abbreviations: af, anconeal fossa; dp, deltopectoral crest; hh, humeral head; ltf, lateral triceps fossa; mtf, medial triceps fossa.
(As you can see, the photography is rather better than in my own illustrations, which I made independently some years ago.)
Of course Paul has had an eye on this work, on and off, since the early 1990s. Then in the late 2000s, when I was working on Xenoposeidon and other Wealden sauropods, I started work independently on a redescription — which of course is why I prepared the figures that have appeared in the last few posts. But that work petered out as I started working more on other specimens and on the problems of the sauropod neck. More recently, Paul and Phil hunkered down and got the nitty-gritty descriptive work done.
Once they had a complete draft manuscript, they very graciously invited me onto the authorship — not something they had to do, but they chose to based on my previous interest in the specimen. My contribution was minor: I provided two of the illustrations, tidied up the early versions of several others, and did an editing pass on the text.
Upchurch et al. (2015: figure 1). Map showing England and Wales, with boundaries for English counties. The magnified inset shows the Isle of Wight and East and West Sussex in more detail, marking the positions of selected major towns/cities and the fossil localities mentioned in the main text. Based on “English ceremonial counties 1998” by Dr. Greg, http://en.wikipedia.org/wiki/File:English_ceremonial_counties_1998.svg. CC By-SA 3.0.
(This map is one of the two illustrations that I provided; the other is the multi-view photograph of the Pelorosaurus conbeari humerus.)
I’m grateful to Paul and Phil, both for inviting me onto this project, and for taking into account my strong preference for an open-access venue. It’s largely because of the latter that the paper now appears in PLOS ONE, where the glorious colour illustrations appear at full resolution and may be re-used for any purpose subject to attribution.
So: what actually is Haestasaurus? Is it the early titanosaur that we’ve all been assuming? The unexciting answer is: we don’t really know. Our paper contains three phylogenetic hypotheses (all of them Paul and Phil’s work, I can’t take any credit). These results are from adding Haestasaurus to the Carballido and Sander (2014) matrix, to the Mannion et al. (2013) standard discrete matrix and to the Mannion et al. (2013) continuous-and-discrete matrix. Only the last of these recovers Haestasaurus as a titanosaur — as sister to Diamantinasaurus and then Malawisaurus, making it a lithostrotian well down inside Titanosauria.
Both both of the other analyses find Haestasaurus as a very basal macronarian — outside of Titanosauriformes. Here is the result of the analysis based on Carballido and Sander’s Europasaurus matrix:
![Upchurch et al. (2105: figure 15). Strict consensus tree (CSM). A strict consensus tree based on the 28 most parsimonious trees generated by analysis of the Carballido and Sander [19] data matrix with the addition of Haestasaurus and six new characters (Tendaguria excluded a priori). GC values (multiplied by 100) are shown in square brackets for all nodes where these values are greater than 0. The monophyletic Diplodocoidea has been collapsed to a single branch in order to reduce figure size. Abbreviation: Brc, Brachiosauridae.](https://svpow.files.wordpress.com/2015/06/upchurchetal-haestasaurus-fig15.jpeg)
Upchurch et al. (2105: figure 15). Strict consensus tree (CSM). A strict consensus tree based on the 28 most parsimonious trees generated by analysis of the Carballido and Sander [19] data matrix with the addition of Haestasaurus and six new characters (Tendaguria excluded a priori). GC values (multiplied by 100) are shown in square brackets for all nodes where these values are greater than 0. The monophyletic Diplodocoidea has been collapsed to a single branch in order to reduce figure size. Abbreviation: Brc, Brachiosauridae.
So it looks like Haestasaurus is either a very basal macronarian or a pretty derived titanosaur. We don’t know which.
But, hey, at least it has a proper name now!
Acknowledgements
It’s Matt’s birthday today. I’d like to dedicate a sauropod to him, but I don’t have the authority to do that. So instead, I dedicate this blog-post to him, and declare it the Mathew J. Wedel Memorial Blog Post.
References
- Carballido, Jose L., and P. Martin Sander. 2013. Postcranial axial skeleton of Europasaurus holgeri (Dinosauria, Sauropoda) from the Upper Jurassic of Germany: implications for sauropod ontogeny and phylogenetic relationships of basal Macronaria. Journal of Systematic Palaeontology 12(3):335-387. doi:10.1080/14772019.2013.764935
- Mannion, Philip D., Paul Upchurch, Rosie N. Barnes and Octávio Mateus. 2013. Osteology of the Late Jurassic Portuguese sauropod dinosaur Lusotitan atalaiensis (Macronaria) and the evolutionary history of basal titanosauriforms. Zoological Journal of the Linnean Society 168(1):98–206. doi:10.1111/zoj.12029
- Upchurch, Paul, Philip D. Mannion and Micahel P Taylor. 2015. The Anatomy and Phylogenetic Relationships of “Pelorosaurus” becklesii (Neosauropoda, Macronaria) from the Early Cretaceous of England. PLoS ONE 10(6):e0125819. doi:10.1371/journal.pone.0125819
Engaging with the media
April 27, 2015
We’ve been fortunate in having several of our papers get considerable attention in the mass media, and we’ve blogged a bit about how to make that happen more easily. The bottom line is that no-one knows which stories will take off and which ones will not, but you can stack the deck in your favor by making things as easy as possible for reporters.
- Xenoposeidon week, day 1-and-a-half: the media
- Sauropod neck posture: the world responds
- Brontomerus in magazines: preparing for the media
Making your story easily accessible for reporters is just a subset of making it accessible for any audience, so Tutorial 16: giving good talks is also relevant here.
Not all media interactions go smoothly. As an example, here are the links to the Clash of the Dinosaurs saga:
YPM 1980: Brontosaurus excelsus, the animal formerly known as Apatosaurus excelsus, the animal formerly known as Brontosaurus excelsus.
Today is a good day for sauropod science. Since we’re not getting this up until the afternoon, you’ve probably already seen that Emanuel Tschopp and colleagues have published a monstrous specimen-level phylogenetic analysis of Diplodocidae and, among other things, resurrected Brontosaurus as a valid genus. The paper is in PeerJ so you can read it for free (here).
I’ve already been pinged by lots of folks asking for my thoughts on this. I know that the return of Brontosaurus is what’s going to catapult this paper into the spotlight, but I hope what everyone takes away from it is just what a thorough piece of work it is. I’ve never seen so many phylogenetic characters illustrated so well. It sets a new standard, and anyone who wants to overturn this had better roll up their sleeves and bring a boatload of data. I’m also very, very happy that it’s open-access so everyone in the world can see it, use it, question it, tear it apart or build on it. Getting Brontosaurus back is just gravy. Although, being pro-brontosaur enough to have named a dinosaur in honor of Brontosaurus, I’m also pretty happy about that. If you need a quick guide to who’s who now, A. ajax and A. louisae are still Apatosaurus, and B. excelsus, B. yahnahpin (formerly Eobrontosaurus), and B. parvus (originally Elosaurus) are all Brontosaurus. For more details, go read the paper.
Apatosaurus lousiae CM 3018: still Apatosaurus. Photo from Wikipedia.
My personal feelings aside, a lot of people are asking how solid is this generic re-separation. I haven’t read the entire paper yet – it’s 299 pages long, for crying out loud – but the separation of Brontosaurus and Apatosaurus seems solid enough. Tschopp et al. didn’t do it lightly, they justify their decision in detail. I don’t hold with the idea that just because two taxa are sisters, means that they cannot be separated generically. As usual in phylogenetic taxonomy, it comes down to what we decide as a community constitutes “diagnosably distinct”. Tschopp et al. have actually put some thought into what that might mean here, and whether you agree with them or not, they’ve at least made all of their evidence and reasoning explicit. That’s both an opportunity and a challenge for critics: an opportunity to pin down exactly where and why you may disagree, and a challenge to do exactly that. You can’t just sit back and say, “I think the analysis is flawed” or “I wouldn’t have coded that character that way” (well, you can, but if that’s all you say, no-one is obliged to take that kind of lazy, drive-by criticism seriously). There are 477 characters here, most of them illustrated, for 81 OTUs, and a lot of post-hoc discussion of the results. So whether you agree with the authors or not, in whole or in part, both fans and critics should dig in and build on this work. Is it the last word on diplodocid taxonomy? Of course not. But it does move the field forward significantly, and the Tschopp et al. should be applauded for that.
There’s a lot more in there than just bringing back Brontosaurus. “Diplodocus” hayi is elevated to its own genus, Galeamopus. Neither of those things are super surprising. There have been rumors since the 90s at least that Brontosaurus might be coming back, and everyone has known for a while that D. hayi was a bit wonky. I was also not surprised to see Australodocus returned to Diplodocidae – when I saw the type material in 2011, it looked diplodocid to me (based on some characters I’ll have to unpack in some other post). More surprising to me are the sinking of Dinheirosaurus into Supersaurus, the finding that Tornieria is not particularly close to Diplodocus, and the uncertain positions of AMNH 460, the American Museum mount, which is an indeterminate apatosaurine pending further study, of FMNH 25112, the Field Museum “Apatosaurus”, which might not even be an apatosaurine at all(!). In several cases, Tschopp et al. come right out and say that X is going to need further study, so if you want to work on sauropods and you’re stuck for project ideas, go see what needs doing.
AMNH 460: we don’t know who this is anymore.
As I was scanning the paper again while composing the last paragraph, I almost fell down the rabbit hole. So much interesting stuff in this paper. Even if all you care about is morphology, the hundred or so figures illustrating the phylogenetic characters ought to keep you happy for a very long time. I look forward to reading through the vertebral characters in detail and seeing what I’ve been missing all these years.
I’m contractually obliged to point out that the authors chose to publish the complete peer-review history of the paper, so you can see what the editor (Andy Farke) and reviewers had to say. As always, I think this transparency (and credit for the reviewers) is great for science, and I can’t wait until it’s the norm at more journals.
FMNH 25112: what even IS that thing?
In addition to the paper, there’s also an interview with lead author Emanuel Tschopp on the PeerJ blog, and a nice shout-out for SV-POW!
Parting shot: why did Tschopp et al. get different results than anyone had previously? Because they used more specimens and more taxa – more data full stop. That’s also why their paper warrants serious consideration. It’s serious work. Let’s go stand on their shoulders.
Reference
(2015) A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda) PeerJ 3:e857 https://dx.doi.org/10.7717/peerj.857
You can predict how rabbits run by looking at their skulls (using this one weird trick!)
March 17, 2015
Meet some of my new friends: (A) Brachylagus idahoensis, (B) Lepus capensis, (C) Poelagus marjorita, (D) Pronolagus crassicaudatus, (E) Lepus americanus, (F) Oryctolagus cuniculus, (G) Nesolagus timminsi, (H) Bunolagus monticularis, and (I) Romerolagus diazi. Kraatz et al. (2015: fig. 1).
I have a new paper out today in PeerJ: “Ecological correlates to cranial morphology in leporids (Mammalia, Lagomorpha)”, with coauthors Brian Kraatz, Emma Sherratt, and Nick Bumacod. Get it free here.
I know, I know, I have fallen from grace. First Aquilops, now rabbits. And, and…skulls! I know what you’re thinking: that maybe I’m not just experimenting with the non-vertebrae of non-sauropods anymore – maybe I have an actual problem. But I don’t. I can quit anytime! You’ll see.
Actually rabbits are the freakiest of all mammals and their skulls are wicked cool. They have double incisors, with the second set right behind the first, hence the name Duplicidentata for rabbits and their close relatives. They have weird fenestrations in their maxillae (pretty much all taxa) and parietal and occipital bones (some more than others) – I’ll come back to that in a bit. And, as we discuss in our new paper, you can tell something about how a rabbit runs by looking at its skull. I thought it would be fun to relate how we figured that out, and why.
A long time ago in a graduate seminar far, far away…
1950: DuBrul, Laskin, and Moss
I met Brian Kraatz at Berkeley, where he and I were part of the cohort of students that came into the Integrative Biology Department in the fall of 2001 (faithful readers may remember Brian from his work tracking oliphaunts from, gosh, three years ago already). We took a lot of classes together, including a seminar by Marvalee Wake on evolutionary morphology. I’m pretty sure that seminar was the first time I’d actually read DuBrul and Laskin (1961), “Preadaptive potentialities of the mammalian skull: an experiment in growth and form”, or as I think of it, “How to turn a rat skull into a pika skull for fun and profit.”
Pikas (Ochotonidae) are the sister group to rabbits (Leporidae) and together these groups make up crown Lagomorpha. If you’re not familiar with pikas, Brian describes them as starting with bunny rabbits and then making them even cuter and cuddlier. Seriously, go do an image search for ‘pika’ and try not to die of cute overload.
Pikas are interesting because in many ways their skulls are intermediate between those of rodents, especially rats, and rabbits. This is maybe not surprising since rodents are the sister group to lagomorphs and are united with them in the clade Glires. E. Lloyd DuBrul was all over this rat-pika-rabbit thing back in the mid-twentieth century. Here’s an illustration from DuBrul (1950: plate 2; labels added by me):
So DuBrul knew from pikas and in particular he had the idea that you could maybe just tweak a rat skull – say, by knocking out the basicranial sutures in a baby rat to limit the growth of the skull base – and produce a gently domed skull like that of a pika. That’s what DuBrul and Laskin (1961) is all about. They did that experiment and here are their results (DuBrul and Laskin (1961: plate 3). Normal rat skull on the right, and dotted in the bottom diagram; experimental “pika-morph” rat skull on the left, and solidly outlined below.
What’s going on here morphogenetically is that the facial skeleton is getting tilted down and away from the back end of the skull. DuBrul was hip to that, too – here’s a relevant image from his 1950 paper (plate 4; labels added by me):
The common reference point against which these skulls are registered is the cranial base (the floor of the braincase just forward of the foramen magnum). Again, the pika is a pretty good intermediate between the rat and a ‘normal’ rabbit, and the dang-near-dog-sized Flemish Giant rabbit takes the lagomorph face-tilting thing to its extreme. (‘Flemish Giant rabbit’ is another entertaining image search that I will leave you as homework.)
Turns out there’s another way you can get rat skulls with different geometries: you can cut off their legs and make them walk on two feet. In an experiment that you might have trouble getting past an Institutional Animal Care and Use Committee today, Moss (1961) lopped off the forefeet or hindfeet in two experimental batches of rats, to see what effect this would have on their skulls. I’ll let Moss speak for himself on this one (Moss, 1961: pp. 301-303, emphasis in the original):
Circumnatal amputation of the forelimbs has successfully produced what are in essence “bipedal rats,” i.e., rats whose habitual mode of kinetic and static posture is permanently altered. […] The animals never became bipedal in the exact sense; that is, they never walked erect on two limbs at all times. […] Nevertheless, bipedal posture and motion were more frequently observed than in controls. […]
Animals whose hind limbs were removed represented another picture. They most certainly did not walk about on their intact forelimbs. Neither did they seem able to use their hind limb stumps as satisfactory substitutes. Their gait was not uniform and seemed to consist in a series of short pushes or hops. The most noticeable thing about them was, among other things, apparent accentuation of their cervical vertebral curvature. The sum of these changes was an upward rotation of the skull.
He wasn’t kidding: when the two groups of bipedal rats grew up, their facial skeletons were tilted relative to the control group, but in different directions (Moss, 1961: fig 3; ‘fore’ and ‘hind’ refer to which limbs the animals had left to locomote with):
Brian and I read Moss back at Berkeley, too. In fact, we were minor Moss junkies. If you’re interested in how living forms come into being, you owe it to yourself to read Moss (1968), “A theoretical analysis of the functional matrix”.
The upshot of all of this is that although neither Brian nor I had done anything with our deep (and, okay, deeply weird) knowledge of how to experimentally jack up rat skulls by the time we graduated from Berkeley, we were also primed to be thinking about how skulls attain their shapes – especially the skulls of rodents and rabbits.
2009: American Museum of Natural History
I went to the AMNH in February, 2009, to visit Brian, who was on a postdoc there at the time, and to spend one day looking at sauropods with Mike, who was over from England for a conference. What Brian and I planned to work on was the fenestration of rabbit skulls, because I’m always interested in the strategic loss of bone from skeletal structures. We spent probably half a day talking about that, and I filled a whole page in my notebook with related noodlings:
But as the sketch on the right shows, it didn’t take us long to figure out that there was something even more interesting to do with rabbit skulls. Brian had a whole shedload of rabbit skulls from different taxa sitting on his desk, and we noticed pretty quickly that one of the primary ways they varied was in the tilt of the facial skeleton relative to the back of the skull. Here’s the very next page of my notes from that trip:
Compare to Kraatz et al. (2015: fig. 2)
The skull up top belongs to Caprolagus, the Hispid hare, which I tend to think of as the “bulldozer hare”. Seriously, it looks like a tank. It doesn’t bound or even hop, it scrambles. Here, stare into the abyss:
That rabbit will cut you, man. And just look at how flat its skull is. Even in life Caprolagus looks more rodent-y than rabbit-y. Or, more precisely, more Ochotona-y.
At the the other extreme are taxa like Bunolagus and Pronolagus, which really push the “I’m going to cute you to death by dint of my incredible bunnosity” thing:
As Brian and I started going through skulls of as many extant rabbits as we could, we noticed that the flatter-skulled taxa, with less pronounced facial tilt, tended to be the stolid, foursquare scramblers like Caprolagus, whereas the speed demons tended to have more strongly tilted skulls. It also seemed like the latter group were achieving that pronounced facial tilt by changing the geometry of the occipital region of the skull. Look back up at the red quadrilaterals I drew on the Caprolagus and Bunolagus skulls in my notebook – those mark the basioccipital ventrally and the dorsal exposure of the supraoccipital. Perhaps unsurprisingly, supraoccipital length is not the whole story; it turns out that some face-tilters get that way by having longer or more strongly arched parietals, BUT it remains true that if you find a rabbit skull with a long dorsal exposure of the supraoccipital, it will also have pronounced facial tilt.
ANYWAY, by my last night in New York, Brian and I decided that the best way to attack this would be to go down to the basement and stay up most of the night drinking beer and measuring rabbit skulls. We then tried to correlate the various measurements and angles with information on the locomotor and burrowing habits of each species. That was a big job, and after a couple of years with little forward progress (to be fair, Brian was moving across the country and taking his first tenure-track job in this interval, and I was helping birth a sauropod) we brought in Brian’s graduate student, Nick Bumacod, to do most of it. Later on the three of us were forced to acknowledge that we knew enough statistics to get ourselves into trouble but not enough to get back out. Brian had taken a geometric morphometrics course for which Emma Sherratt was a TA, and he started bugging her for help with the stats. Emma has been involved in writing new software packages for R, and we realized that the paper would be a lot stronger if we just brought her on as an author and gave her free rein with the data. Along the way Brian and Nick were giving presentations on the project everywhere from the local Western Area Vert Paleo meeting to the World Lagomorph Conference in Vienna. I got my name on four abstracts along the way, which I think is record abstract-to-paper ratio for me (especially considering that 90% of my effort on the paper was invested in a single evening in 2009 over a couple of six-packs).
But enough navel-gazing, what did we find?
2015: Rabbit skulls reveal their mode of locomotion
Our results, which you can read for free, support the hunch that Brian and I had back in 2009: slow-moving rabbits that locomote by scrambling or scampering instead of hopping tend to have less facial tilt, and faster-moving saltatorial (hopping) and cursorial (leaping and bounding) rabbits have more facial tilt. Interestingly, facial tilt does not distinguish the saltators from the cursors. So the break here is between scrambling and any kind of hopping or leaping, but not between hoppers and leapers.
Kraatz et al. (2015: fig. 5a)
Why would that be so? We don’t know for sure yet, but our top hypothesis is that if you’re moving fast, it pays to see the ground in front of you more clearly, and getting your nose down out of the way probably helps with that. This is pretty similar to the hypothesis that tyrannosaurs have pinched nasals for better binocular vision (Stevens, 2006). Rabbits are prey animals and probably can’t afford to point their eyes forward, and they may need wide nasal airways as air intakes while they’re sprinting. Tilting the nose down may be the next best thing.
Some circumstantial support for this comes from the Caviidae, the family of South American rodents that includes guinea pigs, cavies, maras, and capybaras. Here’s another plate from DuBrul (1950: plate 6) contrasting the flatter skull of the guinea pig (Cavia porcellus, top) with the decidedly arched skull of the mara or Patagonian hare (Dolichotis magellanica, bottom). Compare the mara skull to the sectioned rabbit skull in the other DuBrul plate, above – there aren’t a lot of obvious characters to separate the two (beyond the lack of double incisors in the mara).
Mara photo from Wikipedia
Despite being commonly referred to as ‘hares’ and looking a lot like short-eared rabbits, maras are rodents that evolved their rabbit-like form independently. The acquisition of pronounced facial tilt in two separate lineages of small fast-moving herbivorous mammals is further evidence for the influence of locomotor mode on skull form. Irritatingly, I think we neglected to mention the guinea pig : mara :: pika : rabbit correspondence in the paper. Oh well, it wasn’t our novel observation, and we did cite DuBrul (1950).
Relevant to the next paragraph: DILU is ‘diastema length upper’ and BLD is ‘bulla diameter’. Kraatz et al. (2015: fig. 4).
We found lots of other interesting things, too. The PCA plots we produced from our data separate the living rabbits in unexpected ways. The length of the diastema (the toothless portion of the upper jaw) and the diameter of the auditory bulla seem to be particularly important. Diastema length isn’t too hard to figure out – most of the face-tilters have long diastemas, and the flat-heads tend to have short ones. We have no idea what bulla diameter means yet. I mean, obviously something to do with hearing, but we don’t have any ecological variables in our analysis to address that because we didn’t see it coming. So there’s a chunk of new science waiting to be done there.
Speaking of new science, or at least a relatively new thing in science, we published the full peer-review history alongside the paper, just as Mike and I did back in 2013 and as Mike did with his stand-alone paper last December. More than 80% of PeerJ authors elect to publish the peer review histories for their papers. I can’t wait until it’s 100%. PeerJ reviews are citeable – each one gets a DOI and instructions on how to cite it – and I’m tired of having my effort as a peer reviewer used once and then thrown away forever.
If you’ve been reading this whole post with gritted teeth, wondering why we were using linear measurements instead of geometric morphometrics, chillax. Brian and Emma are on that. They’ve been CT scanning the skulls of as many extant rabbits as possible and plotting landmarks for 3D morphometrics – if you were at SVP last fall, you may have seen their talk (Kraatz and Sherratt, 2014). So stay tuned for what will soon be a new ongoing series, Rabbit Skulls: The Next Generation. (Update: pilot episode here.)
I probably won’t be on that voyage. I’ve had fun getting acquainted with a completely different part of the tree of life, but there are an awful lot of shards of excellence – busted-up sauropod vertebrae, that is – crying out for my attention, and I need to stop neglecting them. I’m done with rabbit skulls, I promise. I’m going clean. (Wish me luck!)
References
- DuBrul, E. L. (1950). Posture, locomotion and the skull in Lagomorpha. American Journal of Anatomy, 87(2), 277-313.
- DuBrul, E. L., & Laskin, D. M. (1961). Preadaptive potentialities of the mammalian skull: an experiment in growth and form. American Journal of Anatomy, 109(2), 117-132.
- Kraatz, B., and Sherratt, E. (2014). Evolution, ecology, and modularity of the lagomorph skull. Journal of Vertebrate Paleontology, 35(3, Supplement), 162A.
- Kraatz, B.P., Sherratt, E., Bumacod, N., and Wedel, M.J. 2015. Ecological correlates to cranial morphology in leporids (Mammalia, Lagomorpha). PeerJ, 3:e844. https://dx.doi.org/10.7717/peerj.844
- Moss, M. L. (1961). Rotation of the otic capsule in bipedal rats. American Journal of Physical Anthropology, 19(3), 301-307.
- Moss, M. L. (1968). A theoretical analysis of the functional matrix. Acta Biotheoretica, 18(1), 195-202.
- Stevens, K. A. (2006). Binocular vision in theropod dinosaurs. Journal of Vertebrate Paleontology, 26(2), 321-330.
Reconstructing the skull of Aquilops
December 11, 2014
As I mentioned in my first post on Aquilops, I drew the skull reconstructions that appear in figure 6 of the paper (Farke et al. 2014). I’m writing this post to explain that process.
We’ve blogged here before about the back-and-forth between paleontologists and artists when it comes to reconstructing and restoring extinct animals (example 1, example 2). Until now, I’ve always been the guy making suggestions about the art, and asking for changes. But for the Aquilops project, the shoe was on the other foot: Andy Farke was my ‘client’, and he had to coach me through drawing a basal ceratopsian skull – a subject that I was definitely not familiar with.
I started from the specimen, OMNH 34557, which is more complete than you might think at first glance. The skull is folded over about 2/3 of the way up the right orbit, so in lateral view it looks like the top of the orbit and the skull roof are missing. They’re actually present, just bent at such a sharp angle that they’re hard to see at the same time as the lateral side of the skull.
I also used a cast skull of Archaeoceratops as a reference – it’s clear from what we have of Aquilops that the two animals were pretty similar.
I started with this pencil outline on a piece of tracing paper.
And then I went right ahead and stippled the whole thing, without showing it to Andy until I was done. Yes, that was dumb. Noe the lack of sutures in this version.
I added sutures and sent it off to Andy, who sent it back with these suggested changes. At this point I realized my error: I had already spent about a day and a half putting ink on the page, and I’d have to either start all over, or do a lot of editing in GIMP. I picked the latter course, since there were plenty of areas that were salvageable.
Next I did something that I’d never done before, which is to redraw parts of the image and then composite them with the original in GIMP. Here’s are the redrawn bits.
With those bits composited in, and a few more tweaks to sutures, we got to this version, which was included in the submitted manuscript.
Then we brought Brian Engh in to do the life restorations. When Brian takes on a project, he does his homework. If you’ve seen his post on painting Aquilops, you know that all of the ferns in the Cloverly scene are based on actual fossils from the Cloverly Formation. Brian came to Claremont this summer and he and Andy and I spent most of a day at the Alf Museum looking at the specimen and talking about possible layouts for the full-body life restorations. He took a bunch of photos of the specimen while he was there, and a day or two later he sent us this diagram. He’d chopped up his photos of the skull to produce his own undistorted version to guide his painting, and in doing so he’d noticed that I had the line of the upper jaw a bit off.
That required another round of digital revisions to fix. It ended up being a lot more work than the earlier round of edits in GIMP, because so many features of the skull had to be adjusted. I ended up cutting my own skull recon into about 8 pieces and then stitching them back together one by one. Here’s what the image looked like about halfway through that process. The back of the skull, orbit, and beak are all fixed here, but the snout, cheek, and maxilla don’t yet fit together.
After a little more work, I got the whole thing back together, and this is the final version that appears in the paper. It is not perfect – the area in front of the orbit where the frontal, nasal, maxilla, and premaxilla come together is a bit dodgy, and I’m not totally happy with the postorbital. But eventually you have to stop revising and ship something, and this is what I shipped.
I did the dorsal view after the submitted version of the lateral view was finished. It went a lot faster, for several reasons:
- Most of the gross proportional issues were already sorted out from doing the lateral view first.
- The bilateral symmetry didn’t cut down on the number of dots but it did cut the conceptual workload in half.
- I did all my roughs in pencil and didn’t start inking until after we had almost all of the details hashed out.
I did have to revise the dorsal view after getting feedback from Brian about the lateral view, but that revision was pretty minor by comparison. I stretched the postorbital region and tinkered a bit with the face and the frill, and both of those steps required putting in some new dots, but it was still just one afternoon’s worth of work. Here’s the final dorsal recon:
In addition to the Life Lessons already noted in this post, I learned (or rather relearned) this important principle: if you do a big drawing and then shrink it down to column width, fine errors – a shaky line here, an ugly dot there – get pushed down below the threshold of perception. But there’s a cost, too, which is that uneven stippling becomes more apparent. I was skipping back and forth a lot between 25% image scale to see where the problem areas were, and 200% to revise the lines and dots accordingly.
All in all, it was a fun project. It was my most ambitious technical illustration to date, I learned a ton about ceratopsian skulls, and it was nice to get to make at least one substantial contribution to the paper.
Now, here’s the take-away: this is my reconstruction, and both of those words are important. “Reconstruction” because it has a lot of extrapolation, inference, and sheer guesswork included. “My” because you’re getting just one possible take on this. You can download the 3D files for the cranium and play with them yourselves. I hope that other artists and scientists will use those tools to produce their own reconstructions, and I fully expect that those reconstructions will differ from mine. I look forward to seeing them, and learning from them.
For other posts about my stippled technical illustrations, see:
Reference
Please welcome Aquilops americanus
December 10, 2014
Life restoration of Aquilops by Brian Engh. Farke et al. (2014: fig. 6C). CC-BY.
Today sees the description of Aquilops americanus (“American eagle face”), a new basal neoceratopsian from the Cloverly Formation of Montana, by Andy Farke, Rich Cifelli, Des Maxwell, and myself, with life restorations by Brian Engh. The paper, which has just been published in PLOS ONE, is open access, so you can download it, read it, share it, repost it, remix it, and in general do any of the vast scope of activities allowed under a CC-BY license, as long as we’re credited. Here’s the link – have fun.
Obviously ceratopsians are much more Andy’s bailiwick than mine, and you should go read his intro post here. In fact, you may well be wondering what the heck a guy who normally works on huge sauropod vertebrae is doing on a paper about a tiny ceratopsian skull. The short, short version is that I’m here because I know people.
OMNH 34557, the holotype of Aquilops
The slightly longer version is that OMNH 34557, the holotype partial skull of Aquilops, was discovered by Scott Madsen back in 1999, on one of the joint Cloverly expeditions that Rich and Des had going on at the time (update: read Scott’s account of the discovery here). That the OMNH had gotten a good ceratopsian skull out of Cloverly has been one of the worst-kept secrets in paleo. But for various complicated reasons, it was still unpublished when I got to Claremont in 2008. Meanwhile, Andy Farke was starting to really rock out on ceratopsians at around that time.
For the record, the light bulb did not immediately go off over my head. In fact, it took a little over a year for me to realize, “Hey, I know two people with a ceratopsian that needs describing, and I also know someone who would really like to head that up. I should put these folks together.” So I proposed it to Rich, Des, and Andy in the spring of 2010, and here we are. My role on the paper was basically social glue and go-fer. And I drew the skull reconstruction – more on that in the next post.
One of the world’s smallest ceratopsians meets one of the largest: the reconstructed skull of Aquilops with Rich Cifelli and Pentaceratops for scale. Copyright Leah Vanderburg, courtesy of the Sam Noble Oklahoma Museum of Natural History.
Anyway, it’s not my meager contribution that you should care about. I am fairly certain that, just as Brontomerus coasted to global fame on the strength of Paco Gasco’s dynamite life restoration, whatever attention Aquilops gets will be due in large part to Brian Engh’s detailed and thoughtful work in bringing it to life – Brian has a nice post about that here. I am very happy to report that the three pieces Brian did for us – the fleshed-out head that appears at the top of this post and as Figure 6C in the paper, the Cloverly environment scene with the marauding Gobiconodon, and the sketch of the woman holding an Aquilops – are also available to world under the CC-BY license. So have fun with those, too.
Finally, I need to thank a couple of people. Steve Henriksen, our Vice President for Research here at Western University of Health Sciences, provided funds to commission the art from Brian. And Gary Wisser in our scientific visualization center used his sweet optical scanner to generate the hi-res 3D model of the skull. That model is also freely available online, as supplementary information with the paper. So if you have access to a 3D printer, you can print your own Aquilops – for research, for teaching, or just for fun.
Cloverly environment with Aquilops and Gobiconodon, by Brian Engh (CC-BY).
Next time: Aquilöps gets röck döts.
Reference
Tutorial 29, Appendix A: good, bad and ugly titles of Mike’s papers
October 21, 2014
In light of yesterday’s tutorial on choosing titles, here are the titles of all my own published papers (including co-authored ones), in chronological order, with my own sense of whether I’m happy with them now I look back. All the full references are on my publications page (along with the PDFs). I’ll mark the good ones in green, the bad ones in red and the merely OK in blue.
The Phylogenetic Taxonomy of Diplodocoidea (Dinosauria: Sauropoda).
OK, I suppose. It does at least clearly state what the paper is about. I’ll give myself a pass on this since it was my very first paper.
Dinosaur diversity analysed by clade, age, place and year of description.
NOT BAD, since the paper was basically a list of many, many results that could hardly have been summarised in the title. I give myself some points for listing the ways I analysed the data, rather than just saying “An analysis of dinosaur diversity” or something equally uninformative.
Phylogenetic definitions in the pre-PhyloCode era; implications for naming clades under the PhyloCode.
NOT BAD again, I suppose, since it was a discussion paper that couldn’t be summarised in a short title. Could I have said what the alluded-to implications are? I think probably not, in a reasonably concise title.
An unusual new neosauropod dinosaur from the Lower Cretaceous Hastings Beds Group of East Sussex, England.
RUBBISH, since it doesn’t name the new dinosaur (which was of course Xenoposeidon). I was young and stupid back then, and just followed convention. In mitigation, it does at least say when and where the specimen is from.
Case 3472: Cetiosaurus Owen, 1841 (Dinosauria, Sauropoda): proposed conservation of usage by designation of Cetiosaurus oxoniensis Phillips, 1871 as the type species.
DOUBLE-PLUS UGLY. But I am going to blame the journal on this one — they have a very firmly defined format for petition titles.
Head and neck posture in sauropod dinosaurs inferred from extant animals.
RUBBISH. What was I thinking, and why did my SV-POW!sketeer co-authors let me choose such an uninformative title? We should of course have gone with a title that says what posture we inferred. The associated blog-post had a much better title: Sauropods held their necks erect … just like rabbits.
A re-evaluation of Brachiosaurus altithorax Riggs 1903 (Dinosauria, Sauropoda) and its generic separation from Giraffatitan brancai (Janensch 1914).
ADEQUATE, since the title strongly implies the conclusion (generic separation) even if doesn’t quite come out and say it.
Electronic publication of nomenclatural acts is inevitable, and will be accepted by the taxonomic community with or without the endorsement of the Code.
BRILLIANT. The best title in my CV. You hardly even need to read the paper once you’ve read the title. The only downside: it’s 12 characters too long to tweet.
Sharing: public databases combat mistrust and secrecy.
GOOD, but I can’t take the credit for that (A) because I was third author behind Andy Farke and Matt, and (B) because the journal chose the title.
The Open Dinosaur Project.
OK, but we should have done better. Something like “The Open Dinosaur Project recruits volunteer effort to analyse dinosaur evolution”. Or, if we were being honest (and prescient), “The Open Dinosaur Project will lie embarrassingly moribund for more than two years”.
Sauropod dinosaur research: a historical review.
OK, since it does say what the paper is. But this title is not as good as that of the talk it was based on, “The evolution of sauropod dinosaurs from 1841 to 2008”. (I notice that Mark Witton nicked my title for his talk at TetZooCon.)
Running a question-and-answer website for science education: first hand experiences.
UNOBJECTIONABLE, but not my choice anyway — lead author Dave Hone presumably picked it. Could have done better by stating what at least one of those experiences was.
A new sauropod dinosaur from the Lower Cretaceous Cedar Mountain Formation, Utah, USA.
RUBBISH. At least this time it wasn’t entirely my fault. When we submitted this to Acta Palaeontologica Polonica, it was called “Brontomerus mcintoshi, a new sauropod dinosaur from the Lower Cretaceous Cedar Mountain Formation, Utah, USA”, but the journal made us take the taxon name out of the title. Why? Why why WHY?
The long necks of sauropods did not evolve primarily through sexual selection.
SWEET.
Why sauropods had long necks; and why giraffes have short necks.
EXCELLENT. Short, appealing and (hopefully) funny. When I give talks based on this paper, I use the even better short version, just “Why giraffes have short necks”. But that seemed a bit too cute for an academic setting.
Neural spine bifurcation in sauropod dinosaurs of the Morrison Formation: ontogenetic and phylogenetic implications.
WEAK. We should have stated the conclusion: a title like “Neural spine bifurcation in sauropods of the Morrison Formation is not an ontogenetic feature, but is phylogenetically significant” would have been better.
The neck of Barosaurus was not only longer but also wider than those of Diplodocus and other diplodocines.
GOOD. Not particularly exciting, but explicit.
Caudal pneumaticity and pneumatic hiatuses in the sauropod dinosaurs Giraffatitan and Apatosaurus.
NOT GOOD ENOUGH. We should have stated the main finding: “Caudal pneumaticity and pneumatic hiatuses reveal cryptic diverticula in the sauropod dinosaurs Giraffatitan and Apatosaurus“.
The effect of intervertebral cartilage on neutral posture and range of motion in the necks of sauropod dinosaurs.
UGH, rubbish. What the heck was I thinking? I should have written this post a couple of years ago, and used it to make me choose a much better title. As it is, it just leaves the reader assuming intervertebral cartilage probably has some effect, but they have no idea what.
—
I make that six good titles, seven bad ones and six indifferent. Awarding two points per good title and one per adequate title, I give myself 18 points out of a possible 38 — slightly less than half, at 47%. More worryingly, there’s no apparent trend towards choosing better titles.
Must do better.
Guest post: the genesis of Davide Bonadonna’s Spinosaurus painting
September 16, 2014
In the last post I pointed out some similarities between Davide Bonadonna’s new Spinosaurus painting and Brian Engh’s Spinosaurus painting from 2010. I also suggested that Davide might have borrowed from Brian and might have crossed a line in doing so. I was mistaken about that, as this post will show, and I’m sorry.
I woke up this morning to find that Mike and Davide had a very fruitful and collegial discussion going in email, which they had kindly copied me on. Davide had offered to send his in-progress sketches, Mike had offered to put them up here as a guest post, “because it’ll be a fascinating post — NOT as any kind of defense” (his words, with which I fully agree), and Davide had kindly assented (Brian’s post on how his Spinosaurus came to be is on his own blog). Davide and I corresponded directly this morning and he’s been very gracious and generous with his time, thoughts, and art.
We are always thrilled when we have the opportunity to show how awesome paleoart came into being (like this and this), and this case is no exception. Best now if I just get out of the way, so — over to Davide!
— Matt
——————-
About the illustration:
In early November 2013, I was commissioned by NGMag, via Nizar Ibrahim of the University of Chicago, to create an illustration for a page in the October 2014 issue.
Working for about six years with Simone Maganuco, co-author of the study, on the Spinosaurus (I made the digital model from which the model exhibited in Washington was printed, Nizar left us carte blanche.
Some key points were essential, however: showing the Spinosaurus while swimming, his webbed feet, show its prey in the environment of Kemkem, possibly including all the major players in the scene, Mawsonia, Alanqa and Carcharodontosaurus.
Problems: the Spinosaurus is very long, the subjects to be represented too many. It was decided first of all to exclude the Carcharodontosaurus and then framing a foreshortened Spinosaurus, which would allow us to make room for the actors. Given the size and shape of Spinosaurus we knew that we would inevitably get what I call the “Luis Rey-effect” style. So, after gathering plenty of references, I made my sketches, suggesting a frontal dynamic sight (4) and a back view (1-2-3), presenting both solutions to Nizar at last SVP in L.A.
1
2
3
4
Meanwhile the size of the final art had to be changed because from the mag they asked for a double opening page of the article. And in the same time, thanks to a friend suggestion, I drew a third version (5), with the Idea to put all them together (8).
5
8
But the scene was too crowded and we decided to use just two animals, so I tried different combinations (6).
6
And the best one was to put both frontal versions together, one close to the other (7).
7
And again the two-pages image had to be changed because NG decided to turn it in a three-pages wide illustration, something that helped me to put Mawsonia in the background (9).
9
When finished, before approval, the NG editorial staff asked me to put an animal familiar to the modern public, which could help the reader to feel how big was the Spinosaurus, and a turtle was the chosen one (10).
10
Brian Engh’s illustration:
I vaguely remember I once had seen Brian’s illustration before today and I did not put it in my archive as a reference. All my main references are these: crocodile photos, patchworks made with my 3D digital model and Dinoraul one (11).
11
The water view comes from an NG poster about marine reptiles (12).
12
Most of my illustrations have a fisheye distortion, this is not the first one I make (see on my website Scipionyx, Neptunidraco, Diplodocus–Allosaurus and others).
You can easily see from the sketches progress how a traditional vanishing point becomes gradually a curve.
Conclusion:
This is a case of illustrative convergence. ;-)
That’s all folks, I think. If you have any other doubt, just ask. I’m at your disposal.
Best,
Davide
http://www.davidebonadonna.it/
https://www.facebook.com/pages/Davide-Bonadonna/286308368137641?fref=ts
Sauropod Vertebra Picture of the Week 
