Can we distinguish taphonomic distortion and (paleo)pathology from normal biological variation?
February 12, 2021
Taylor 2015: Figure 8. Cervical vertebrae 4 (left) and 6 (right) of Giraffatitan brancai lectotype MB.R.2180 (previously HMN SI), in posterior view. Note the dramatically different aspect ratios of their cotyles, indicating that extensive and unpredictable crushing has taken place. Photographs by author.
Here are cervicals 4 and 8 from MB.R.2180, the big mounted Giraffatitan in Berlin. Even though this is one of the better sauropod necks in the world, the vertebrae have enough taphonomic distortion that trying to determine what neutral, uncrushed shape they started from is not easy.
Wedel and Taylor 2013b: Figure 3. The caudal vertebrae of ostriches are highly pneumatic. This mid-caudal vertebra of an ostrich (Struthio camelus), LACM Bj342, is shown in dorsal view (top), anterior, left lateral, and posterior views (middle, left to right), and ventral view (bottom). The vertebra is approximately 5cm wide across the transverse processes. Note the pneumatic foramina on the dorsal, ventral, and lateral sides of the vertebra.
Here’s one of the free caudal vertebrae of an ostrich, Struthio camelus, LACM Ornithology Bj342. It’s a bit asymmetric–the two halves of the neural spine are aimed in slightly different directions, and one transverse process is angled just slightly differently than the other–but the asymmetry is pretty subtle and the rest of the vertebral column looks normal, so I don’t think this rises to the level of pathology. It looks like the kind of minor variation that is present in all kinds of animals, especially large-bodied ones.
This is a dorsal vertebra of a rhea, Rhea americana, LACM Ornithology 97479, in posteroventral view. Ink pen for scale. I took this photo to document the pneumatic foramina and related bone remodeling on the dorsal roof of the neural canal, but I’m showing it here because in technical terms this vert is horked. It’s not subtly asymmetric, it’s grossly so, with virtually every feature–the postzygapophyses, diapophyses, parapophyses, and even the posterior articular surface of the centrum–showing fairly pronounced differences from left to right.
That rhea dorsal looks pretty bad for dry bone from a recently-dead extant animal, but if it was from the Morrison Formation it would be phenomenal. If I found a sauropod vertebra that looked that good, I’d think, “Hey, this thing’s in pretty good shape! Only a little distorted.” The roughed-up surface of the right transverse process might give me pause, and I’d want to take a close look at those postzygs, but most of this asymmetry is consistent with what I’d expect from taphonomic distortion.
Which brings me to my titular question, which I am asking out of genuine ignorance and not in a rhetorical or leading way: can we tell these things apart? And if so, with what degree of confidence? I know there has been a lot of work on 3D retrodeformation over the past decade and a half at least, but I don’t know whether this specific question has been addressed.
Corollary question: up above I wrote, “It looks like the kind of minor variation that is present in all kinds of animals, especially large-bodied ones”. My anecdotal experience is that the vertebrae of large extant animals tend to be more asymmetric than those of small extant animals, but I don’t know if that’s a real biological phenomenon–bone is bone but big animals have larger forces working on their skeletons, and they typically live longer, giving the skeleton more time to respond to those forces–OR if the asymmetry is the same in large and small animals and it’s just easier to see in the big ones.
If either of those questions has been addressed, I’d be grateful for pointers in the comments, and thanks in advance. If one or both have not been addressed, I think they’re interesting but Mike and I have plenty of other things to be getting on with and we’re not planning to work on either one, hence the “Hey, you! Want a project?” tag.
References
- Taylor, Michael P. 2015. Almost all known sauropod necks are incomplete and distorted. PeerJ Preprints 3:e1767. doi:10.7287/peerj.preprints.1418v1
- Wedel, Mathew J., and Michael P. Taylor. 2013. Caudal pneumaticity and pneumatic hiatuses in the sauropod dinosaurs Giraffatitan and Apatosaurus.PLOS ONE 8(10):e78213. 14 pages. doi:10.1371/journal.pone.0078213 [PDF]
Long before Matt and others were CT-scanning sauropod vertebrae to understand their internal structure, Werner Janensch was doing it the old-fashioned way. I’ve been going through old photos that I took at the Museum für Naturkunde Berlin back in 2005, and I stumbled across this dorsal centrum:
Dorsal vertebra centum of ?Giraffatitan in ventral view, with anterior to top.
You can see a transverse crack running across it, and sure enough the front and back are actually broken apart. Here there are:
The same dorsal vertebral centrum of ?Giraffatitan, bisected transversely in two halves. Left: anterior half in posterior view; right: posterior half in anterior view. I had to balance the anterior half on my shoe to keep it oriented corrrectly for the photo.
This does a beautiful job of showing the large lateral foramina penetrating into the body of the centrum and ramifying further into the bone, leaving only a thin midline septum.
But students of the classics will recognise this bone immediately as the one that Janensch (1947:abb. 2) illustrated the posterior half of in his big pneumaticity paper:
It’s a very strange feeling, when browsing in a collection, to come across a vertebra that you know from the literature. As I’ve remarked to Matt, it’s a bit like running into, say, Cameron Diaz in the corner shop.
Reference
- Janensch, W. 1947. Pneumatizitat bei Wirbeln von Sauropoden
und anderen Saurischien. Palaeontographica, supplement
7:1-25.
Remember this broken Giraffatitan dorsal vertebra, which Janensch figured in 1950?
It is not only cracked in half, anteroposteriorly, it’s also unfused.
Here’s a better view of the broken face, more clearly showing that the neural canal is (a) much taller than wide – unlike all vertebrate spinal cords – and (b) almost entirely situated ventral to the neurocentral joint, getting close to the condition in the perverted Camarasaurus figured by Marsh.
Here’s a dorsal view, anterior to the top, with Mike’s distal forelimbs for scale.
Left lateral view.
Right lateral view – note the subtle asymmetries in the pneumatic foramen/camera. A little of that might be taphonomic distortion but I think much of it is real (and expected, most pneumatic systems produce asymmetries).
And postero-dorsal view, really showing the weird neural canal to good advantage. In this photo and in the pure dorsal view, you can see that the two platforms for the “neural arch” – which, as in the aforementioned Camarasaurus, is neither neural nor an arch – converge so closely as to leave only a paper-thin gap.
A few points arise. As explained in this post, it makes more sense to talk about the neurocentral joint migrating up or down relative to the neural canal, which is right where it always is, just dorsal to the articular faces of the centrum.
So far, in verts I’ve seen with “offset” neurocentral joints, the joint tends to migrate dorsally in dorsal vertebrae, putting the canal inside the developmental domain of the centrum (which now includes a partial or total arch in an architectural sense, even though the chunk of bone we normally call the neural arch develops as a separate bit) – as shown in the first post in this series. In sacral and caudal vertebrae, the situation is usually reversed, with the joint shifted down into what would normally be the centrum, and the canal then mostly or completely surrounded by the arch – as shown in the second post in the series. This post then doesn’t really add any new concepts, just a new example.
Crucially, we can only study this in the vertebrae of juveniles and subadults, because once the neurocentral joints are fused and remodeled, we usually can’t tell where the old joint surface was. So it’s like cervicodorsal and caudal dorsal pneumatic hiatuses, in that the feature of interest only exists for part of the ontogeny of the animal, and our sample size is therefore inherently limited. Not necessarily limited by material – most museums I’ve visited have a fair amount of juvenile and subadult material in the collections – but limited in published visibility, in that for many sauropods only the largest and most complete specimens have been monographically described.
So once again, the answer is simply to visit collections, look at lots of fossils, and stay alert for weird stuff – happily, a route that is open to everyone with a legitimate research interest.
Reference
- Janensch, W. 1950. Die Wirbelsaule von Brachiosaurus brancai. Palaeontographica (Suppl. 7) 3:27-93.
Paul Graham on blogging as a way to generate papers
January 16, 2018
Computer programmer, essayist and venture capitalist Paul Graham writes:
In most fields, prototypes have traditionally been made out of different materials. Typefaces to be cut in metal were initially designed with a brush on paper. Statues to be cast in bronze were modelled in wax. Patterns to be embroidered on tapestries were drawn on paper with ink wash. Buildings to be constructed from stone were tested on a smaller scale in wood.
What made oil paint so exciting, when it first became popular in the fifteenth century, was that you could actually make the finished work from the prototype. You could make a preliminary drawing if you wanted to, but you weren’t held to it; you could work out all the details, and even make major changes, as you finished the painting.
You can do this in software too. A prototype doesn’t have to be just a model; you can refine it into the finished product. I think you should always do this when you can. It lets you take advantage of new insights you have along the way. But perhaps even more important, it’s good for morale.
– Paul Graham, “Design and Research”
Mike and I have long been drawn by the idea that blog posts, like conference talks and posters, could be first drafts of research papers. In practice, we haven’t generated many successful examples. We basically wrote our 2013 neural spine bifurcation paper as a series of blog posts in 2012. And Mike’s 2014 neck cartilage paper grew out of this 2013 blog post, although since he accidentally ended up writing 11 pages I suppose the blog post was more of a seed than a draft.
I should also note that we are far from the first people to do the blog-posts-into-papers routine. The first example I know of in paleo was Darren’s Tet Zoo v1 post on azhdarchid paleobiology, which formed part of the skeleton of Witton and Naish (2008).
Nevertheless, the prospect of blogging as a way to generate research papers remains compelling.
And as long as I’m on about blogging and papers: sometimes people ask if blogging doesn’t get in the way of writing papers. I can’t speak for anyone else, but for me it goes in the opposite direction: I blog most when I am most engaged and most productive, and drops in blogging generally coincide with drops in research productivity. I think that’s because when I’m rolling on a research project, I am constantly finding or noticing little bits that are cool and new, but which aren’t germane to what I’m working on at the moment. I can’t let those findings interfere with my momentum, but I don’t want to throw them away, either. So I blog them. Also the blog gives me a place to burn off energy at the end of the day, when I can still produce words but don’t have the discipline to write technical prose.
– – – – – – – – – – – –
The photo at the top of the post is of Giraffatitan dorsal vertebrae in a case at the MfN Berlin, from Mike’s and my visit with the DfG 533 group back in late 2008. I picked that photo so I could make the following dumb off-topic observation: with its upturned transverse processes, the dorsal on the right looks like it’s being all faux melodramatic, a la:
Ten years of sauropod vertebrae!
October 1, 2017
Amazingly (to me, anyway), SV-POW! is ten years old today. It was on 1st October 2007 that we published Hello world!, our first post, featuring a picture of what may still be our favourite single sauropod vertebra: the ?8th cervical of the Giraffatitan brancai paralectotype MB.R.2181. Of course, back then, we thought it was the type (it’s not), it was thought to belong to Brachiosaurus brancai (mea culpa), and the specimen number was HMN SII. A lot has changed in ten years, but the vertebra is still heart-breakingly beautiful.
Some other things have changed in those ten years, of course. Three of us started the blog, but one (Darren) has become a sleeping partner due to the enormous success of his other blog, Tetrapod Zoology. We began intending to be a picture blog, but we’ve ended up as a 50-50 blend of sauropod palaeontology and open-access advocacy. Along the way, I (Mike) got my Ph.D, and Matt moved from UC Merced to Western University of Health Sciences, where both he and his wife Vicki now have tenure. Darren meanwhile has carved out a unique niche for himself as a writer and consultant, and has his own cconference.
We never thought this blog would run for so long — I seem to remember the original plan was to make 52 weekly posts, then call it a day after one year. In fact, over the last ten years, we’ve posted 1160 articles, for an average of one every 3.15 days: more than twice as often as the weekly schedule that the blog title suggests. But not all those posts have included sauropod vertebrae — so, guessing that about half of them have, we’re more or less on target.
In the mean time, you have written 16820 comments, for a pretty healthy average of 14.5 per post. One of the things I’m proudest about regarding this blog is that we’ve only once had to shut a thread down because it became unproductive; and I think on only two other occasions have we had to issue a public warning. We have a fantastic community of commenters here, and my deeply felt gratitude goes out to you all.
Our most-read post at the time of writing is Every attempt to manage academia makes it worse (with 214,438 views), followed by Elsevier is taking down papers from Academia.edu (62,695), SV-POW! showdown: sauropods vs whales (35,944) and How big was Amphicoelias fragillimus? I mean, really? (35,531). These lead a list of 35 posts that have each garnered more than 10,000 views, contributing to an overall total of 3,573,821 views (which gives us an average of 3,080 views per post). We are alternately delighted, baffled and impressed that the world has shown such interest.
We have one or two things planned for this week of the 10th anniversary, but for this post I just want to leave it like this: THANK YOU ALL for reading, commenting and engaging with this blog. Thank you, palaeontologists for putting up with the open-access posts, and thank you scholarly communication specialists for putting up with the sauropods. We hope it’s been interesting, entertaining and sometimes thought-provoking; and we hope we can continue in the same vein. (We certainly have no plans to stop any time soon.)
We love you guys.
How horrifying was the neck of Barosaurus?
September 16, 2016
Suppose that I and Matt were right in our SVPCA talk this year, and the
“Supersaurus” cervical BYU 9024 really is the C9 of a gigantic Barosaurus. As we noted in our abstract, its total length of 1370 mm is exactly twice that of the C9 in AMNH 6341, which suggests its neck was twice as long over all — not 8.5 m but 17 m.
How horrifying is that?
I realised one good way to picture it is next to the entire mounted skeleton of Giraffatitan at the Museum für Naturkunde Berlin. That skeleton is 13.27 m tall. At 17 m, the giant barosaur neck would be 28% longer than the total height of Giraffatitan.
Giraffatitan brancai mounted skeleton MB.R.2181 at the Museum für Naturkunde Berlin, with neck of Barosaurus ?lentus BYU 9024 at the same scale. Photo by Axel Mauruszat, from Wikipedia; drawing from Scott Hartman’s Supersaurus skeleton reconstruction.
Yes, this looks ridiculous. But it’s what the numbers tell us. Measure the skeleton’s height and the neck length off the image yourself if you don’t believe me.
(Note, too, that the size of the C9 in that big neck is about right, compared with a previous scaled image that Matt prepared, showing the “Supersaurus” vertebra in isolation alongside the Chicago Brachiosaurus.)
Copyright: promoting the Progress of Science and useful Arts by preventing access to 105-year-old quarry maps
October 11, 2015
In my recent preprint on the incompleteness and distortion of sauropod neck specimens, I discuss three well-known sauropod specimens in detail, and show that they are not as well known as we think they are. One of them is the Giraffatitan brancai lectotype MB.R.2181 (more widely known by its older designation HMN SII), the specimen that provides the bulk of the mighty mounted skeleton in Berlin.
That photo is from this post, which is why it’s disfigured by red arrows pointing at its epipophyses. But the vertebra in question — the eighth cervical of MB.R.2181 — is a very old friend: in fact, it was the subject of the first ever SV-POW! post, back in 2007.
In the reprint, to help make the point that this specimen was found extremely disarticulated, I reproduce Heinrich (1999:figure 16), which is Wolf-Dieter Heinrich’s redrawing of Janensch’s original sketch map of Quarry S, made in 1909 or 1910. Here it is again:
Taylor 2015: Figure 5. Quarry map of Tendaguru Site S, Tanzania, showing incomplete and jumbled skeletons of Giraffatitan brancai specimens MB.R.2180 (the lectotype, formerly HMN SI) and MB.R.2181 (the paralectotype, formerly HMN SII). Anatomical identifications of SII are underlined. Elements of SI could not be identified with certainty. From Heinrich (1999: figure 16), redrawn from an original field sketch by Werner Janensch.
For the preprint, as for this blog-post (and indeed the previous one), I just went right ahead and included it. But the formal version of the paper (assuming it passes peer-review) will by very explicitly under a CC By licence, so the right thing to do is get formal permission to include it under those terms. So I’ve been trying to get that permission.
What a stupid, stupid waste of time.
Heinrich’s paper appeared in the somewhat cumbersomely titled Mitteilungen aus dem Museum fur Naturkunde in Berlin, Geowissenschaftliche Reihe, published as a subscription journal by Wiley. Happily, that journal is now open access, published by Pensoft as The Fossil Record. So I wrote to the Fossil Record editors to request permission. They wrote back, saying:
We are not the right persons for your question. The Wiley Company holds the copyright and should therefore be asked. Unfortunately, I do not know who is the correct person.
I didn’t know who to ask, either, so I tweeted a question, and copyright guru Charles Oppenheim suggested that I email permissions@wiley.com. I did, only to get the following automated reply:
Dear Customer,
Thank you for your enquiry.
We are currently experiencing a large volume of email traffic and will deal with your request within the next 15 working days.
We are pleased to advise that permission for the majority of our journal content, and for an increasing number of book publications, may be cleared more quickly by using the RightsLink service via Wiley’s websites http://onlinelibrary.wiley.com and www.wiley.com.
Within the next fifteen working days? That is, in the next three weeks? How can it possibly take that long? Are they engraving their response on a corundum block?
So, OK, let’s follow the automated suggestion and try RightsLink. I went to the Wiley Online Library, and searched for journals whose names contain “naturkunde”. Only one comes up, and it’s not the right one. So Wiley doesn’t admit the existence of the journal.
Despite this, Google finds the article easily enough with a simple title search. From the article’s page, I can just click on the “Request Permissions” link on the right, and …
Well, there’s lots to enjoy here, isn’t there? First, and most important, it doesn’t actually work: “Permission to reproduce this content cannot be granted via the RightsLink service.” Then there’s that cute little registered-trademark symbol “®” on the name RightsLink, because it’s important to remind me not to accidentally set up my own rights-management service with the same name. In the same vein, there’s the “Copyright © 2015 Copyright Clearance Center, Inc. All Rights Reserved” notice at the bottom — copyright not on the content that I want to reuse, but on the RightsLink popup itself. (Which I guess means I am in violation for including the screenshot above.) Oh, and there’s the misrendering of “Museum für Naturkunde” as “Museum für Naturkunde”.
All of this gets me precisely nowhere. As far as I can tell, my only recourse now is to wait three weeks for Wiley to get in touch with me, and hope that they turn out to be in favour of science.
It’s Sunday afternoon. I could be watching Ireland play France in the Rugby World Cup. I could be out at Staverton, seeing (and hearing) the world’s last flying Avro Vulcan overfly Gloucester Airport for the last time. I could be watching Return of the Jedi with the boys, in preparation for the forthcoming Episode VII. Instead, here I am, wrestling with copyright.
How absolutely pointless. What a terrible waste of my life.
Is this what we want researchers to be spending their time on?
Promoting the Progress of Science and useful Arts, indeed.
Update (13 October 2015): a happy outcome (this time)
I was delighted, on logging in this morning, to find I had email from RIGHTS-and-LICENCES@wiley-vch.de with the subject “Permission to reproduce Heinrich (1999:fig. 16) under CC By licence” — a full thirteen working days earlier than expected. They were apologetic and helpful. Here is key part of what they said:
We are of course happy to handle your request directly from our office – please find the requested permission here:We hereby grant permission for the requested use expected that due credit is given to the original source.If material appears within our work with credit to another source, authorisation from that source must be obtained.Credit must include the following components:– Journals: Author(s) Name(s): Title of the Article. Name of the Journal. Publication year. Volume. Page(s). Copyright Wiley-VCH Verlag GmbH & Co. KGaA. Reproduced with permission.
So this is excellent. I would of course have included all those elements in the attribution anyway, with the exception that it might not have occurred to me to state who the copyright holder is. But there is no reason to object to that.
So, two cheers for Wiley on this occasion. I had to waste some time, but at least none of it was due to deliberate obstructiveness, and most importantly they are happy for their figure to be reproduced under CC By.
References
- Heinrich, Wolf-Dieter. 1999. The taphonomy of dinosaurs from the Upper Jurassic of Tendaguru, Tanzania (East Africa), based on field sketches of the German Tendaguru expedition (1909-1913). Mitteilungen aus dem Museum fur Naturkunde in Berlin, Geowissenschaftliche Reihe 2:25-61.
My name is Giraffatitan, king of kings
April 30, 2015
Look on my works, ye mighty, and despair!
[Giraffatitan brancai paralectotype MB.R.2181 (formerly HMN S II), mounted skeleton in left anteroventrolateral view. Presacral vertebrae sculpted, skull scaled and 3d-printed from specimen T1. Round the decay of that colossal wreck, boundless and bare, the lone and level sands stretch far away.]
Sauropod Vertebra Picture of the Week 