January 26, 2017
It’s now been widely discussed that Jeffrey Beall’s list of predatory and questionable open-access publishers — Beall’s List for short — has suddenly and abruptly gone away. No-one really knows why, but there are rumblings that he has been hit with a legal threat that he doesn’t want to defend.
To get this out of the way: it’s always a bad thing when legal threats make information quietly disappear; to that extent, at least, Beall has my sympathy.
That said — over all, I think making Beall’s List was probably not a good thing to do in the first place, being an essentially negative approach, as opposed to DOAJ’s more constructive whitelisting approach. But under Beall’s sole stewardship it was a disaster, due to his well-known ideological opposition to all open access. So I think it’s a net win that the list is gone.
But, more than that, I would prefer that it not be replaced.
Researchers need to learn the very very basic research skills required to tell a real journal from a fake one. Giving them a blacklist or a whitelist only conceals the real issue, which is that you need those skills if you’re going to be a researcher.
Finally, and I’m sorry if this is harsh, I have very little sympathy with anyone who is caught by a predatory journal. Why would you be so stupid? How can you expect to have a future as a researcher if your critical thinking skills are that lame? Think Check Submit is all the guidance that anyone needs; and frankly much more than people really need.
Here is the only thing you need to know, in order to avoid predatory journals, whether open-access or subscription-based: if you are not already familiar with a journal — because it’s published research you respect, or colleagues who you respect have published in it or are on the editorial board — then do not submit your work to that journal.
It really is that simple.
So what should we do now Beall’s List has gone? Nothing. Don’t replace it. Just teach researchers how to do research. (And supervisors who are not doing that already are not doing their jobs.)
March 7, 2016
This one is for journalists and other popularizers of science. I see a lot of people writing that “scientists believe” this or that, when talking about hadrons or hadrosaurs or other phenomena grounded in evidence.
Pet peeve: believing is what people do in the absence of evidence, or despite evidence. Scientists often have to infer, estimate, and even speculate, but all of those activities are grounded in evidence and reason, not belief.1
In addition to doing science, scientists may also believe in the proper, spiritual sense, in which case you are free to explain what certain individual scientists believe. But that’s not how the word “believe” is used most of the time when it comes up in science stories.
So stop it. It’s lazy, and it’s damaging, because it gives (some) people the impression that scientists are clueless buffoons who make stuff up out of the whole cloth in a cynical bid to keep their jobs. Given that we have an entire political party pushing that view and trying to defund science and education at every turn, we don’t need that caricature promoted any further.
Even if you don’t accept that argument, it’s still bad writing. Good writing explains why people think as they do. So do that instead. In addition to the aforementioned “infer”, “estimate”, and “speculate”, you can use “surmise”, “reason”, “predict”, or – if you must – “think”. “Scientists have found” would be better still.
Best of all would be if the “scientists X” clause was preceded by, “Based on this evidence” (which you’ve just explained in the previous sentences), so readers can connect cause (evidence) and effect (scientists think) – which is what science is mostly about in the first place.
1. I realize that I am grossly oversimplifying – evidence, reason, and belief can interact in complicated ways in both spiritual and scientific spheres. But my purpose here is fixing poor word choice, not exploring that interaction.
February 29, 2016
Functional Anatomy of the Vertebrates: An Evolutionary Perspective, by Liem et al. (2001), is by some distance my favorite comparative vertebrate anatomy text. When I was a n00b at Berkeley, Marvalee Wake assigned it to me as preparatory reading for my qualifying exams.
The best textbooks, like Knut Schmidt-Nielsen’s Animal Physiology (which deserves a post or even series of its own sometime), have a clarity of writing and illustration that makes the fundamentals of life seem not only comprehensible, but almost inevitable – without losing sight of the fact that nature is complex and we don’t know everything yet. FAotV has both qualities, in spades.
I’m writing about this now because Willy Bemis, second author on FAotV, has just made ALL of the book’s illustrations available for free on his website, in a series of 22 PowerPoint files that correspond to the 22 chapters of the book. All told they add up to about 155 Mb, which is trivial – even the $5 jump drives in the checkout lanes at department stores have five to ten times as much space.
Of course, to get the full benefit you should also pick up a copy of the book. I see used copies going for under $40 in a lot of places online. Mine will have pride of place on my bookshelf until I enter the taphonomic lottery. And I’ll be raiding these PPTs for images from now until then, too.
So do the right thing, and go download this stuff, and use it. Be sure to credit Liem et al. (2001) for the images, and thank Willy Bemis for making them all available. It’s a huge gift to the field. Here’s that link again.
But wait – that’s not all! Starting on June 28, Dr. Bemis will be one of six faculty members from Cornell and the University of Queensland teaching a 4-week massively open online course (MOOC) on sharks. Freakin’ sharks, man!
“What did you do this summer? Hang out and play Nintendo?”
“Yep. Oh, and I also took a course on freakin’ sharks from some awesome shark experts. You?”
As the “massively open” part implies, the course is free, although you have the option of spending $49 to get a certificate of completion (assuming you finish satisfactorily). Go here to register or get more info.
- Liem, K.F., Bemis, W.E., Walker, W.F., and Grande, L. 2001. Functional Anatomy of the Vertebrates. (3rd ed.). Thomson/Brooks Cole, Belmont, CA.
That paper that says women are better coders than men but are judged on their gender? It doesn’t say that at all
February 20, 2016
As a long-standing proponent of preprints, it bothers me that of all PeerJ’s preprints, by far the one that has had the most attention is Terrell et al. (2016)’s Gender bias in open source: Pull request acceptance of women versus men. Not helped by a misleading abstract, we’ve been getting headlines like these:
- Study: Female Coders Better Than Men, But Perceived As Worse (LiveScience)
- Women accepted as better coders as long as no gender link (TechXplore)
- Women devs – want your pull requests accepted? Just don’t tell anyone you’re a girl (The Register)
But in fact, as Kate Jeffrey points out in a comment on the preprint (emphasis added):
The study is nice but the data presentation, interpretation and discussion are very misleading. The introduction primes a clear expectation that women will be discriminated against while the data of course show the opposite. After a very large amount of data trawling, guided by a clear bias, you found a very small effect when the subjects were divided in two (insiders vs outsiders) and then in two again (gendered vs non-gendered). These manipulations (which some might call “p-hacking”) were not statistically compensated for. Furthermore, you present the fall in acceptance for women who are identified by gender, but don’t note that men who were identified also had a lower acceptance rate. In fact, the difference between men and women, which you have visually amplified by starting your y-axis at 60% (an egregious practice) is minuscule. The prominence given to this non-effect in the abstract, and the way this imposes an interpretation on the “gender bias” in your title, is therefore unwarranted.
Your most statistically significant results seem to be that […] reporting gender has a large negative effect on acceptance for all outsiders, male and female. These two main results should be in the abstract. In your abstract you really should not be making strong claims about this paper showing bias against women because it doesn’t. For the inside group it looks like the bias moderately favours women. For the outside group the biggest effect is the drop for both genders. You should hence be stating that it is difficult to understand the implications for bias in the outside group because it appears the main bias is against people with any gender vs people who are gender neutral.
Here is the key graph from the paper:
(The legends within the figure are tiny: on the Y-axes, they both read “acceptance rate”; and along the X-axis, from left to right, they read “Gender-Neutral”, “Gendered” and then again “Gender-Neutral”, “Gendered”.)
So James Best’s analysis is correct: the real finding of the study is a truly bizarre one, that disclosing your gender whatever that gender is reduces the chance of code being accepted. For “insiders” (members of the project team), the effect is slightly stronger for men; for “outsiders” it is rather stronger for women. (Note by the way that all the differences are much less than they appear, because the Y-axis runs from 60% to 90%, not 0% to 100%.)
Why didn’t the authors report this truly fascinating finding in their abstract? It’s difficult to know, but it’s hard not to at least wonder whether they felt that the story they told would get more attention than their actual findings — a feeling that has certainly been confirmed by sensationalist stories like Sexism is rampant among programmers on GitHub, researchers find (Yahoo Finance).
I can’t help but think of Alan Sokal’s conclusion on why his obviously fake paper in the physics of gender studies was accepted by Social Text: “it flattered the editors’ ideological preconceptions“. It saddens me to think that there are people out there who actively want to believe that women are discriminated against, even in areas where the data says they are not. Folks, let’s not invent bad news.
Would this study have been published in its present form?
This is the big question. As noted, I am a big fan of preprints. But I think that the misleading reporting in the gender-bias paper would not make it through peer-review — as the many critical comments on the preprint certainly suggest. Had this paper taken a conventional route to publication, with pre-publication review, then I doubt we would now be seeing the present sequence of misleading headlines in respected venues, and the flood of gleeful “see-I-told-you” tweets.
(And what do those headlines and tweets achieve? One thing I am quite sure they will not do is encourage more women to start coding and contributing to open-source projects. Quite the opposite: any women taking these headlines at face value will surely be discouraged.)
So in this case, I think the fact that the study in its present form appeared on such an official-looking venue as PeerJ Preprints has contributed to the avalanche of unfortunate reporting. I don’t quite know what to do with that observation.
What’s for sure is that no-one comes out of this as winners: not GitHub, whose reputation has been wrongly slandered; not the authors, whose reporting has been shown to be misleading; not the media outlets who have leapt uncritically on a sensational story; not the tweeters who have spread alarm and despondancy; not PeerJ Preprints, which has unwittingly lent a veneer of authority to this car-crash. And most of all, not the women who will now be discouraged from contributing to open-source projects.
January 12, 2016
I was a bit disappointed to hear David Attenborough on BBC Radio 4 this morning, while trailing a forthcoming documentary, telling the interviewing that you can determine the mass of an extinct animal by measuring the circumference of its femur.
We all know what he was alluding to, of course: the idea first published by Anderson et al. (1985) that if you measure the life masses of lots of animals, then measuring their long-bone circumferences when they’ve died, you can plot the two measurements against each other, find a best-fit line, and extrapolate it to estimate the masses of dinosaurs based on their limb-bone measurements.
This approach has been extensively refined since 1985, most recently by Benson et al. (2014). but the principle is the same.
But the thing is, as Anderson et al. and other authors have made clear, the error-bars on this method are substantial. It’s not super-clear in the image above (Fig 1. from the Anderson et al. paper) because log-10 scales are used, but the 95% confidence interval is about 42 pixels tall, compared with 220 pixels for an order of magnitude (i.e. an increment of 1.0 on the log-10 scale). That means the interval is 42/220 = 0.2 of an order of magnitude. That’s a factor 10 ^ 0.2 = 1.58. In other words you could have two animals with equally robust femora, one of them nearly 60% heavier than the other, and they would both fall within the 95% confidence interval.
I’m surprised that someone as experienced and knowledgeable as Attenborough would perpetuate the idea that you can measure mass with any precision in this way (even more so when using only a femur, rather than the femur+humerus combo of Anderson et al.)
More: when the presenter told him that not all scientists buy the idea that the new titanosaur is the biggest known, he said that came as a surprise. Again, it’s disappointing that the documentary researchers didn’t make Attenborough aware of, for example, Paul Barrett’s cautionary comments or Matt Wedel’s carefully argued dissent. Ten minutes of simple research would have found this post — for example, it’s Google’s fourth hit for “how big is the new argentinian titanosaur”. I can only hope that the actual documentary, which screens on Sunday 24 January, doesn’t present the new titanosaur’s mass as a known and agreed number.
(To be clear, I am not blaming Attenborough for any of this. He is a presenter, not a palaeontologist, and should have been properly prepped by the researchers for the programme he’s fronting. He is also what can only be described as 89, so should be forgiven if he’s not quite as quick on his feel when confronted with an interviewer as he used to be.)
Update 1 (the next day)
Thanks to Victoria Arbour for pointing out an important reference that I missed: it was Campione and Evans (2012) who expanding Anderson et al.’s dataset and came up with the revised equation which Benson et al. used.
Update 2 (same day as #1)
It seems most commenters are inclined to go with Attenborough on this. That’s a surprise to me — I wonder whether he’s getting a free pass because of who he is. All I can say is that as I listened to the segment it struck me as really misleading. You can listen to it for yourself here if you’re in the UK; otherwise you’ll have to make do with this transcript:
“It’s surprising how much information you can get from just one bone. I mean for example that thigh bone, eight feet or so long, if you measure the circumference of that, you will be able to say how much weight that could have carried, because you know what the strength of bone is. So the estimate of weight is really pretty accurate and the thought is that this is something around over seventy tonnes in weight.”
(Note also that the Anderson et al./Campione and Evans method has absolutely nothing to do with the strength of bone.)
Also if interest was this segment that followed immediately:
How long it was depends on whether you think it held its neck out horizontaly or vertically. If it held it out horizontally, well then it would be about half as big again as the Diplodocus, which is the dinosaur that’s in the hall of the Natural History Museum. It would be absolutely huge.
Interviewer: And how tall, if we do all the dimensions?
Ah well that is again the question of how it holds its neck, and it could have certainly reached up about to the size of a four or five storey building.
Needless to say, the matter of neck posture is very relevant to our interests. I don’t want to read too much into a couple of throwaway comments, but the implication does seem to be that this is an issue that the documentary might spend some time on. We’ll see what happens.
- Anderson, J. F., A. Hall-Martin and D. A. Russell. 1985. Long-bone circumference and weight in mammals, birds and dinosaurs. Journal of Zoology 207:53-61.
- Benson, Roger B. J., Nicolás E. Campione, Matthew T. Carrano, Philip D. Mannion, Corwin Sullivan, Paul Upchurch, and David C. Evans. 2014. Rates of dinosaur body mass evolution indicate 170 million years of sustained ecological innovation on the avian stem lineage. PLOS Biology 12(5):e1001853. doi:10.1371/journal.pbio.1001853
- Campione, Nicolás E., and David C. Evans. 2012. A universal scaling relationship between body mass and proximal limb bone dimensions in quadrupedal terrestrial tetrapods. BMC Biology 10:60 (22 pages). doi:10.1186/1741-7007-10-60
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:
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.
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.
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 fÃ¼r 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?
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.
- 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.
April 13, 2015
We had a short email exchange which quickly converged on, “This would work well for some projects, but not for others.” That’s the same conclusion I came to in my recent review of my own paper titles: I am increasingly enamored of titles that are full sentences, because then if all someone reads is your title, they still know what you found. But not every paper can be summarized so neatly.
Beginning a tight little internet eddy that will be complete at the end of this post, Andy Farke posted my paper title review post on Facebook and it fired some discussion in the comments. Victoria Arbour wrote, “I’m trying to move more towards ‘sentence’ titles, but it’s difficult to come up with something that’s concise, accurate and nuanced sometimes!” I responded, “Totally agreed. There’s no one size fits all solution. I have no idea how John Foster and I could have turned the Snowmass Haplocanthosaurus title into a sentence that wouldn’t have been a disaster. ‘Concise, accurate, and nuanced’ are all good goals, but they pull in different directions.”
But it got me thinking about the different ways that we can craft our results for effective delivery. The default package is long-form: the paper. Not just long, but narrowly targeted: just about every sub-sub-subfield has a core of diehards who will read your paper because it’s right in their wheelhouse and they basically have to, to stay caught up. You were going to reach them anyway. The real question – the question that, iterated over all of your papers, will decide the shape of your career – is who else are you going to reach? The answer is going to depend a lot on serendipity, but you can improve your chances by building something easily digestible – scattering the seeds of your results over as many brains as possible, to increase the number of successful germinations (which in this metaphor could be anything from citations to one-off collaborations to life-long friendships). Here’s what I have so far.
Four ways to efficiently package your results
I almost wrote, “four ways to weaponize and aerosolize your science”. You’re trying to infect people with your ideas. Here are some potential delivery mechanisms.
First, and already mentioned: a good title. Not “Aspects of the history, anatomy, taxonomy and palaeobiology of good heavens I have lost feeling in my extremities” but, whenever possible, something that either tells people what you found (the sentence title) or at least indicates that you found something interesting (the question title, some ‘hook’ titles – “Why giraffes have short necks”). See these three posts for more.
Second, a summary figure. Discussed here. Nice because once people have seen that figure, they basically have your results in one convenient, portable, easily-digestible package. Downside: figures are usually entombed in papers, so this doesn’t count as an outreach maneuver unless you let the figure out into the wild some other way. Blog it, put it on Facebook, do something with it so that it functions as a funnel, catching people and pointing them toward your work.
Third, a punchy poster, like O’Hanlon’s. This has a similar caveat as the summary figure: if the only place people can see it is in its native environment (the paper, the scientific meeting), it’s still only preaching to the converted. Get it out where other people can see it. Second caveat: if the poster doesn’t point to something outside of itself, it doesn’t really count as outreach material. The best part of O’Hanlon’s poster is the QR code. If anyone is unhappy with how brief the poster is, they can follow the link and go down the rabbit hole. The depth of the engagement is in the user’s hands. Corollary: if your poster doesn’t have a QR code or a (tiny)URL, it’s a dead end. Why not make it into a gateway? It’s not a question of either/or, it’s an opportunity for yes/and.
Fourth, an infographic, like this one Victoria Arbour made to summarize some of the results from her big 2013 paper on Alberta ankylosaurs (borrowed from here). I thought it was ingenious when I first saw it (on Facebook), and I still do. You know why? Because I know jack about ankylosaurs, but this thing makes them seem both cool and tractable. Victoria is conveying, “There is structure here, and it makes sense. Let me guide you through it.” I instantly wanted something like this for every group of dinosaurs. You know who will appreciate you building something like this? Every other person besides the half-dozen grognards who work on the exact same thing you do (and maybe them, too). Gratitude leads to citations – people will go out of their way to cite your work just because they want other people to know about it.
Conclusions: give people a destination, give them choices, give them something
Three final points about all of this. First, none of these things work if there’s nowhere for interested parties to go, or nothing for them to find when they get there. If there’s a paper already, it had better justify the interest that made people look at it. Don’t let your catchy title be like the trailer for that movie that was 2 minutes of awesome and 1:58 of zzzzzzz. If there’s no paper yet, what are you pointing people to – a blog, a research website, a PeerJ preprint, some files on FigShare, a YouTube video, your open notebook, what? Give them somewhere to go. Immediate implication: if there’s nowhere else for interested people to go, why are you presenting now? Again: don’t build dead-ends, build gateways.
Next, if you think that crafting a second, tighter package strictly for the purposes of promotion is a bit gauche, here’s another perspective: you’re giving people more choices about how to engage with your work. A paper alone presents a very limited set of options. Read me (or skim me, or look at my figures), or don’t. Some people don’t have the activation energy that requires, and by ‘some people’ I mean everyone outside of your little niche. Most of them will never know that your work even exists. Craft something that will reach those people and give them an easy way in. Even for those closer to home, it may still make their lives easier. Have I actually read Arbour and Currie (2013)? No, but I looked at the pretty figures, because I saw the infographic on Facebook. So when I do need to know something about ankylosaurs (hey, stranger things have happened), I know where to turn – and who to cite. I, the user, have options. Give your users more options, and you may find that you get more users.
Third, it pays to stop and think about how people who aren’t in your narrow sub-sub-subfield are going to find out about your work. Do you have a blog? A Facebook account? Active on a mailing list or a forum? As long as that figure or poster or infographic sits in its native habitat, it’s only reaching the converted. Put it on your blog or on Facebook, now it’s something else, carrying your ideas out into the world: a missive, a missile, a missionary – all from the Latin mittere, ‘to send’. You’re already doing the work. Package it, neatly and tightly, and send it.
– – – – – – –
Many thanks to Victoria Arbour for permission to post her diagram, and for her patience over the 23 months that it has taken me to get around to doing so. You really should go check out Arbour and Currie (2013) – the figures are stunning – and Victoria’s extensive and entertaining series of blog posts that followed. That rabbit hole starts here.
- Arbour VM, Currie PJ (2013) Euoplocephalus tutus and the Diversity of Ankylosaurid Dinosaurs in the Late Cretaceous of Alberta, Canada, and Montana, USA. PLoS ONE 8(5): e62421. doi:10.1371/journal.pone.0062421
- Wedel, M.J., and Taylor, M.P. 2013. Neural spine bifurcation in sauropod dinosaurs of the Morrison Formation: ontogenetic and phylogenetic implications. Palarch’s Journal of Vertebrate Palaeontology 10(1): 1-34. ISSN 1567-2158.