February 28, 2013
From Jensen (1987, page 604):
“In 1985 I found the proximal third of an extremely large sauropod femur (Figs. 8A, 12A) in a uranium miner’s front yard in southern Utah. The head of this femur is 1.67 m (5’6″) in circumference and was collected from the Recapture Creek Member of the the Morrison Formation in Utah near the Arizona border. It is the largest bone I have ever seen.”
Jensen included not one but two figures of this immense shard of excellence. Here they are:
The specimen was heavily reconstructed, as you can see from the big wodge of unusually smooth and light-colored material in the photo. So we can’t put much stock in that part of the specimen.
Unfortunately, the only measurement of the specimen that Jensen gives in the paper is that circumference; there are no straight-line linear measurements, and the figures both have the dreaded scale bars. Why dreaded? Check this out:
As you can see, when the scale bars are set to the same size, the bones are way off (the scale bar in the drawing is 50 cm). This is not an uncommon problem. I make the Fig 8 version 30% bigger in max mediolateral width of the entire proximal end, and still 17% bigger in minimum diameter across the femoral head, as measured from the slight notch on the dorsal surface (on the right in this view).
Can we figure out which is more accurate based on the internal evidence of the paper? For starters, the Fig 12 version is a drawing (1), that does not match the outline from the photo (2), and the hand-drawn scale bar (3) does not actually coincide with any landmarks (4), and that’s plenty of reasons for me not to trust it.
What about that circumference Jensen mentioned? Unfortunately, he didn’t say exactly where he took it, just that the head of the femur had a circumference of 1.67 meters. Is that for the entire proximal end, or for the anatomical head that fits in the acetabulum, er wot? I’m afraid the one measurement given in the paper is no help in determining which of the figures is more accurately scaled.
The obvious thing to do would be to see if this bone is in the BYU collections, and just measure the damn thing. More on that at the end of the post.
In the meantime, Jensen said that the shape of the Recapture Creek femur was most similar to the femur of Alamosaurus, or to that of Brachiosaurus among Morrison taxa, and he referred it to Brachiosauridae. So how does this thing–in either version–compare with the complete femur of FMNH P25107, the holotype of Brachiosaurus altithorax?
The first thing to notice is that the drawn outline from Figure 12 is a much better match for the Brachiosaurus altithorax femur–enough so that I wonder if Jensen drew it from the Recapture Creek specimen, or just traced the B.a. proximal femur and scaled it accordingly (or maybe not accordingly, since the scale bars don’t match).
But let’s get down to business: how long would the complete femur have been?
Using the scale bar in the photograph from Figure 8 (on the left in above image), I get a total femur length of 2.36 meters.
Which is long, but only 7.7% longer than the 2.19-meter femur of FMNH P25107, and therefore only 25% more massive. So, 35 tonnes to Mike’s 28-tonne B.a., or maybe 45 tonnes to a more liberal 36-tonne B.a. Big, yeah, but not world-shattering. Update 2014-05-19: I don’t know where I got the 2.19-meter femur length for Brachiosaurus altithorax, but it’s a mistake. So the rest of that paragraph should read: Which is 16% longer than 2.03-meter femur of FMNH P25107, and therefore 57% more massive. So, 44 tonnes to Mike’s 28-tonne B.a., or maybe 57 tonnes to a more liberal 36-tonne B.a. That’s nowhere near the 2.5-meter femur and estimated 70-tonne mass of the largest Argentinosaurus, but it’s pretty darned good for a brachiosaur.
Using the scale bar in the drawing from Figure 12 (on the right in the above image)–which, remember, is 50 cm, not 1 meter–I get a total femur length of about 1.9 meters, which is considerably smaller than the B.a. holotype. That is very much at odds with Jensen’s description of it as “the largest bone I have ever seen”, and given that we have many reasons for not trusting the scale bar in the drawing, it is tempting to just throw it out as erroneous.
So it would seem that unless Jensen got both scale bars too big, the Recapture Creek brachiosaur was at most only a shade bigger than the holotype specimen of Brachiosaurus altithorax.
But wait–is the Recapture Creek brachiosaur a brachiosaur at all? Jensen didn’t list any characters that pushed him toward a brachiosaurid ID, and I don’t know of any proximal femur characters preserved in the specimen that would separate Brachiosaurus from, say, Camarasaurus. And in fact a camarasaur ID has a lot to recommend it, in that Camarasaurus femora have very offset heads (the ball- or cylinder-like articular surface at the top end sticks out a big more to engage with the hip socket–see Figure 12 up near the top of the post), moreso than in many other Morrison sauropods, and that would make them better matches for the Recapture Creek femur photo. Here’s what the comparo looks like:
I make that a 2.07-meter femur using the photo on the left, and a 1.66-meter femur using the drawing on the right. The one decent femur in the AMNH 5761 Camarasaurus supremus collection is 1.8 meters long, so these results are surprisingly similar to those for the B. althithorax comparison–the drawing gives a femur length shorter than the largest known specimens, and the photo gives a length only slightly longer. A camarasaur with a 2.07 meter femur would be 15% larger than the AMNH C. supremus in linear terms, and assuming isometric scaling, 1.5 times as massive–maybe 38 tonnes to AMNH 5761’s estimated 25. A big sauropod to be sure, but not as big as the largest apatosaurs, and not nearly as big as the largest titanosaurs.
I have always been surprised that the Recapture Creek femur frag has attracted so little attention, given that “Dinosaur Jim” himself called it the biggest bone he had ever seen. But it appears that the lack of attention is justified–whether it was a brachiosaur or a camarasaur, and using the most liberal estimates the scale bars allow, it simply wasn’t that big.
Update about half an hour later: Okay, maybe I was a little harsh here. IF the photo scale bar is right, the Recapture Creek femur might still represent the largest and most massive macronarian from the Morrison Formation (Edit: only if it’s a brachiosaur and not a camarasaur; see this comment), which is something. I suppose I was particularly underwhelmed because I was expecting something up in OMNH 1670-to-Argentinosaurus territory, and so far, this ain’t it. I’ll be interested to see what the actual measurements say (read on).
The Moral of This Story
So, if it wasn’t that big after all, and if no-one has made a stink about it being big before now, why go to all this trouble? Well, mostly just to satisfy my own curiosity. If there was a truly gigantic brachiosaur from the Morrison, it would be relevant to my interests, and it was past time I crunched the numbers to find out.
But along the way something occurred to me: this should be a cautionary tale for anyone who gets all wound up about the possible max size of Amphicoelias fragillimus. As with A. fragillimus, for the Recapture Creek critter we have part of one bone, and at least for this exercise I was working only from published illustrations with scale bars. And as with A. fragillimus, the choice of a reference taxon is not obvious, and the size estimates are all over the place, and some of them just aren’t that big.
It always amuses me when A. fragillimus comes up and people (well, trolls) accuse us of being big ole’ wet blankets that just don’t want to believe in 200-tonne sauropods. It amuses me because it’s wrong on so many levels. Believe me, when we have our sauropod fanboy hats on, we most definitely do want to believe in 200-tonne sauropods. That would rock. But when we put our scientist hats on, wanting and belief go right out the window. We have to take a cold, hard look at the data, and especially at its limitations.
Oh, the other moral is to go buy a tape measure, and use it. Sheesh!
As I said above, the obvious thing to do would be to just track down the bone and measure it. It does still exist, it’s in the BYU collections, and Brooks Britt has kindly offered to send along some measurements when he gets time. So we should have some real answers before long (and here they are). But I wanted to work through this example without them, to illustrate how much uncertainty creeps in when trying to estimate the size of a big sauropod from published images of a single partial bone.
February 27, 2013
I was reading Stephen Curry’s excellent summary of Monday’s Royal Society’s conference on “Open access in the UK and what it means for scientific research”. One point that Stephen made is:
[David Willetts's] argument is that pursuance of green OA leads to an unstable situation in which the cancellation of subscriptions (because readers have free access) drains the system of the funds needed to manage peer review and other publishing costs.
As an analysis of the difficulties of Green OA, this is admirably precise. But my eye was caught by that phrase “funds needed to manage peer review and other publishing costs.”
I think we should make an effort to wean ourselves off the habit of talking about “managing peer review and other publishing costs”. We all recognise that publishers do not provide peer-review — we do. But it’s also true that publishers don’t manage peer-review, either. Once again, we do that, by acting as unpaid academic editors.
I know that this is not news. We all know this. But a habit of speech is affording publishers a degree of credit that their efforts don’t merit, and that clouds the debate. Let’s apportion credit where it belongs.
Of course there are still “other publishing costs”. These are real and not negligible (even though PeerJ’s financial model suggests they are much less than we have sometimes assumed). It’s right that we should acknowledge that there really are publishing costs; and that whatever financial model we end up will need to pay them somehow. But let’s make an effort to be more precise about what those publishing costs are. Managing peer-review is not one of them.
February 27, 2013
Well, this is rad. And adorable. Brian Switek, whom we adore, commissioned a fuzzy juvenile sauropod from Niroot, whom we adore, for his (Brian’s) upcoming book, My Beloved Brontosaurus, which I am gearing up to adore. And here is the result, which I adore, borrowed with permission from Love in the Time of Chasmosaurs.
There is much to like here. Here’s my rundown:
- Small forefeet that are the correct shape: good. Maybe too small, given that young animals often have big feet. But better too small than too big, given how often people screw this up.
- Pronounced forelimb-hindlimb disparity: win.
- Fat neck: pretty good.
In fact, let me interrupt the flow of praise here to put in Brant Bassam’s dorsal view of his mounted Phil Platt model Apatosaurus skeleton. I’ve been meaning to post about this for a while now and haven’t gotten to it, so now’s a good time: just look at how friggin’ FAT that neck is, and how it blends in with the body, and how the tail gets a lot skinnier a lot quicker (and, yeah, caudofemoralis, but not that much). Now, go look at a bunch of life restorations of Apatosaurus–drawings, paintings, sculptures, toys, whatever–and see how many people get this wrong, by giving Apatosaurus a too-skinny neck. The answer is, damn near everyone.
Okay, back to Niroot’s baby:
- Proportionally shorter neck and tail because it’s a juvenile: win.
- Neck wrinkles possibly corresponding to vertebrae: okay, just this once.
- Greenish fuzz possibly functioning as camouflage: We-ell…
Yes, it’s true that all of the known sauropod skin impressions show scales, not fuzz. But. We don’t have anything like full-body coverage. And I suspect that there is a collection bias against fuzzy skin impressions. Scaly skin impressions are probably easier to recognize than 3D feathery skin impressions (as opposed to feathers preserved flat as at Liaoning and Solnhofen) because the latter probably just look like wavy patterns on rock, and who is looking for feather impressions when swinging a pickaxe at a sauropod’s back end? And how many sauropods get buried in circumstances delicate enough to preserve dinofuzz anyway? Also, some kind of fuzz is probably primitive for Ornithodira, and scales do not necessarily indicate that feathers were absent because owl legs. So is this speculative? Yes. Is it out of the question? I think not. In the spirit of Mythbusters, I’m calling it ‘plausible’.
Oh, one more thing: Niroot posted this in honor of Brian Switek’s birthday. Happy birthday, Brian! (You owe me a book!)
My spouse, Vicki, the other Dr. Wedel, is a physical and forensic anthropologist. And she’s one of a very small number of scientists who have (a) learned something new about the human body, and (b) used it to help identify dead people. And since that process involves the sciences of hard-tissue histology and skeletochronology–not to mention lots of dead folks–I reckon it might be of interest here. Hence this post.
This started about a decade ago, when Vicki was working on her PhD under Alison Galloway at UC Santa Cruz. Vicki worked with Alison on a ton of forensic cases, including some you probably heard of–they analyzed the remains of Laci Peterson and her unborn baby, Connor, for Scott Peterson’s murder trial. I had the unusual privilege of assisting a couple of times, on other cases, once to take some pictures in the lab while Vicki fished the skeleton out of the bag of skin that was all that was left of the body, and once to crawl around on my hands and knees picking human finger bones out of a muddy slough near Santa Cruz. All in all, I’m happy that my usual victims have been dead a lot longer.
Incidentally, the only show with forensic content that Vicki will watch voluntarily is Dexter. She cannot stand CSI, NCIS, or the other “behind the scenes” forensic investigation shows. We’ve tried watching them, but the inaccuracies drive her crazy (paleo people: imagine getting the Clockwork Orange therapy and being forced to watch Clash of the Dinosaurs). Real cases are solved by teams of specialists, not two omnicompetent protagonists; it takes weeks or months, not half an hour; and if the forensics people carry guns, it’s because they know waaaay too much about how some very bad, very organized people dispose of bodies (the short answer is, not thoroughly enough*).
* Once a guy who was threatening to testify against a certain criminal organization was shot in the head, his body burned, and his burnt remains scattered along the side of the road. Vicki and Alison picked the bone shards out of the roadside gravel, identified some of them as bits of skull, and found bevelling diagnostic of ballistics trauma on some of those. The way the bone had shattered showed that the gunshot had been inflicted perimortem–around the time of death–and before the body was burned. Bottom line, whatever plan you have to get rid of the body, it is probably not going to be enough to keep someone like Vicki from figuring out how you did it. That much, the TV shows do get right.
Not only is hard to really, truly get rid of a human body, it’s also hard to tell exactly when a person died, especially if all you have is a body in the woods. Insects are good–there’s a whole field of forensic entomology, whose practitioners age cadavers based on what insects are present and what stages of their life cycles they’re in. But what if all that is left is a pile of bones in the woods (which happens more often that you might think, and sometimes for completely innocuous reasons)? I’m preaching to the choir here, but bones can survive for a long time, so general wear-and-tear doesn’t tell you much. Rapetosaurus looks like it died last year.
There’s another side to this, which is figuring out how old someone was at the time of death based on their skeleton. Tooth eruption is good, and fusion of the epiphyseal growth plates, but both of those processes are basically done by the time people are in their mid-20s (teeth) to mid-30s (epiphyseal fusion). After that, there are methods based on the morphology of the auricular surface of the ilium and the public symphyses, but these only narrow things down to intervals of 5 to 15 years, and that’s a lot of missing persons reports to sift through. And none of the regular skeletal methods work past the age of 55 or 60. After that, no matter how healthy you are, the primary skeletal changes are attritional (i.e., you’re wearing out), and that process varies so much among individuals and populations that there are basically no predictive guidelines.
All of this was on Vicki’s mind when she was a grad student, so she was alert to anything that might help forensic anthropologists narrow down the possibilities for identifying dead folks. She was teaching in an osteology course and one of her students, Josh Peabody, brought up dental cementum increment analysis (DCIA), which is used in zooarcheology to determine the age and season at death of animal remains found at archaeological sites. Josh wanted to know if the method worked on humans.
At the time–2004–DCIA was being tested for age at death in some historical human populations from archaeological sites, but no-one had tried using it for season at death. So Vicki and Josh set out to see if it would work.
Our teeth, like those of other mammals, are held in their sockets by periodontal ligaments. The periodontal ligament of each tooth attaches via Sharpey’s fibers to the dental cementum on the tooth root(s). Cementum is laid down in annual bands, so you can count the number of bands on a tooth, add the normal age at which that tooth erupts, and get a pretty tight estimate of when the animal died. So much for age at death, which was already being done on humans in a limited way in the early 2000s, albeit in archaeological rather than forensic contexts.
But wait, there’s more. Actually two bands of cementum are laid down every year–a dark band in the winter (roughly October to March) and a light band in the summer (roughly April to September). ‘Dark’ and ‘light’ describe the appearance of the bands under polarized light microscopy. In the summer months, the collagen fibrils that make up the cementum are aligned parallel to the tooth root, so more light comes through. In the winter, the collagen is aligned perpendicular to the root, so less light is transmitted, and the winter bands appear darker by comparison. So not only does the number of pairs of light-and-dark bands tell you the number of years since the tooth erupted, the color of the outermost band tells you in which six-month period the individual died, and the thickness of the outermost band might help you narrow that down even further.
At least, that’s how it works in other mammals. Would it hold up in humans? After all, we’re pretty good at adjusting our environments to suit us, rather than vice versa. If the winter-summer banding pattern was present in humans, it would be a huge boon to forensic science. Even people in their 40s and beyond with no very reliable skeletal indicators of age could be aged to within a year or two, and their season at death narrowed down to a 2-3 month window.
To find out, Vicki and Josh had a dentist in Santa Cruz collect 112 teeth pulled from patients over the course of a year (with full IRB approval and informed consent from the dental patients). For their purposes, a tooth pulled from a live person is just as good as one from a cadaver or skeleton–extraction kills the tooth as surely as death of the body. Better, even, in that it was easier to quickly get lots of teeth with very precise extraction data.
Vicki and Josh cut a few teeth together and they found dark and light bands right away. They presented those preliminary results at the American Academy of Forensic Sciences meeting in 2005. After that, Josh got busy with his own research, but Vicki pressed on (while finishing a dissertation on different project, and being a first-time mom).
If this was a movie, this is the part where there would be a montage of inspirational music to get us quickly past a lot of hard, boring work. Each of the 112 teeth had to be embedded in plastic, a section through the root cut out with a saw, that section mounted on a slide and ground down until it was translucent (this process will be familiar to bone histologists of all stripes, paleo or neo). Then Vicki had to go all the way around the perimeter of the each root to find the place where the cementum bands showed the most clearly, and count them. This part is trickier than it sounds, unless you’ve done some histo and know just how butt-ugly some sections can be under the scope.
The results? In the words of the Bloodhound Gang, which Vicki quotes in her DCIA talks, “You and me baby ain’t nothin’ but mammals”. Here’s the payoff graph:
The one out-of-place measurement was probably caused by the dark band not being thick enough to register clearly on the image.
Now that she knew that DCIA could be used to determine season at death in humans, Vicki started applying it in her forensic cases, of which there have been many. The vast majority of the work of forensic anthropologists is invisible to the public: after analyzing a set of remains, a forensic anthropologist writes a case report for whatever law enforcement office (or, much less frequently, law firm or other entity) brought them in, and that’s that. The case reports are almost always confidential, but they have to be written to exacting standards since they may be used as evidence in court. So forensic anthropologists spend a lot of time toiling over papers that hardly anyone gets to read.
However, sometimes a case is written up for journal publication–if it’s sufficiently novel or unusual, and if permission can be secured from all of the relevant parties. In 2008, Vicki was approached by the Merced County sheriff’s office to help try to identify the remains of a young woman who had been murdered in 1971. That’s the 37-year-old cold case mentioned in the title of this post, and rather than tell you about it, I’ll point you to Vicki’s case report (Wedel et al. 2013), published last month in the Journal of Forensic Identification and freely available here.
I wasn’t sure whether to post about this or not–as cool as they are, murder cases are not our normal stock in trade on this blog. What decided me was talking with Andy Farke. He read Vicki’s paper as soon as it came out, and he said that he really enjoyed getting to see how forensic anthropologists work in the real world. I sometimes take for granted that, since I am married to a forensic anthropologist, I get to see how this works all the time. But that’s a pretty rare experience–if paleontology is a small field, forensic anthropology is positively tiny. So if you want to see an example of the real science that CSI and the like are based on, here’s your window.
What’s next? Vicki has several validation studies on DCIA in progress, for which she and her collaborators have collected a much larger sample size–over 1000 teeth–to try to answer questions like: what tooth is best to use for DCIA? Should the histological sections be made longitudinally or transversely through the tooth root? Does cementum banding vary with latitude? And since banding patterns are reversed in the Southern Hemisphere, following the flip-flopped season, what happens at the equator? Watch this space, and keep an eye out for Vicki’s future publications–including a book due out next year–at her website, Bodies, Bugs, and Bones.
- Wedel, V.L. 2007b. Determination of season at death using dental cementum increment analysis. Journal of Forensic Sciences 52(6): 1334-1337.
- Wedel, V.L., G. Found, and G.L. Nusse. 2013. A 37 year-old cold case identification using novel and collaborative methods. Journal of Forensic Identification 63(1): 5-21.
February 24, 2013
I was cruising the monographs the other night, looking for new ideas, when the humerus of Opisthocoelicaudia stopped me dead in my tracks. I think you’ll agree it is an arresting sight:
I’d seen it before, but somehow I had never grokked its grotesque fatness. I mean, damn, Opisthocoelicaudia, you really let yourself go. Especially compared to the slenderness and grace of this juvenile Alamosaurus humerus:
Now, I realize that part of the slenderness of this Alamosaurus humerus might be because it’s a juvenile–other alamosaur humeri are a bit more robust–but it’s still a striking contrast. I couldn’t help but superimpose them, scaled to the same midshaft width:
I flipped the Alamosaurus humerus left-to-right to match that astonishing lump of Opisthocoelicaudia. The result reminds me of one of Abrell and Thompson’s Actual Facts:
If you put Woodrow Wilson inside William Howard Taft, he would have stuck out by a good 18 inches.
None of that probably signifies anything more than that I am easily amused. And also, Opisthocoelicaudia is Just Plain Wrong. You hear me, Opisthocoelicaudia? Don’t make me make you cry mayonnaise!
- Borsuk-Bialynicka, M. 1977. A new camarasaurid sauropod Opisthocoelicaudia skarzynskii, gen. n., sp. n. from the Upper Cretaceous of Mongolia. Palaeontologia Polonica 37: 5-64.
- Lehman, Thomas M. and Alan B. Coulson. 2002. A juvenile specimen of the sauropod dinosaur Alamosaurus sanjuanensis from the Upper Cretaceous of Big Bend National Park, Texas. Journal of Paleontology 76(1): 156-172.
February 23, 2013
Well, yesterday was insane.
I happened to be going out yesterday evening; when I left the house it had been the worst day for open access in recent memory. Then when I got back three hours later it was to the news the the US Office of Science and Technology Policy (OSTP) had responded to the #OAMonday petition, issuing a memorandum that greatly increases access to US government-funded research.
So it’s one step back in the UK, two steps forward in America. With my nationalist hat on, it’s a shame to see Britain so cravenly abandon its position of leadership in the worldwide move to open access. But I can’t really care too much about that. Progress towards open access is not a zero-sum game: when America wins, we all win. And when we in the UK win — as we surely win — everyone will benefit from that, too.
I won’t go into details — there’s no need to, as Peter Suber has done a fantastically detailed job of explaining what the new policy does and doesn’t include, and how it resembles and differs from the still very important FASTR legislation. Get yourself over there are read up on the details.
Then crack open a bottle a wine and celebrate. This policy isn’t perfect, no, and there is still a lot of work to do. But it represents significant progress. O happy day.
February 22, 2013
Here’s a timeline of what’s happened with the RCUK’s open access policy (with thanks to Richard Van Noorden for helping to elucidate it).
March 2012: draft policy released for comment. As I noted in my submission, it was excellent. It did not accept non-commercial clauses (on either Gold or Green OA), and allowed Green-OA embagoes of no more that six months (with a twelve-month exception for two humanities councils). “It is anticipated that the revised policy will be adopted in summer 2012″
July 2012: actual policy released. Weakened to allow publishers to impose non-commercial clauses on Green OA. (They didn’t tell anyone they’d made this change, as far as I ever saw. I discovered it for myself.) “The policy applies to all research papers whose work was funded by RCUK being submitted for publication from 1 April 2013″
November 2012: RCUK announce that they will only fund APCs for 45% of articles as Gold OA.
January 2013: RCUK announce that they “will not enforce” embargo periods.
February 2013: In response to House of Lords enquiry, RCUK clarifes “that it will gradually phase in its open access policy over a five year implementation phase”. BIS and RCUK both endorse embargo-period “decision tree” that allows embargoes of up to two years.
At every single step of the way, the RCUK policy has been weakened. From being the best and most progressive in the world, it’s now considerably weaker than policies already in action elsewhere in the world, and hardly represents an increment on their 2006 policy. Crucially, all three of the key differences discussed in March’s draft policy have now been eliminated:
- “Specifically stating that Open Access includes unrestricted use of manual and automated text and data mining tools; and unrestricted reuse of content with proper attribution.” — not if you use Green OA.
- “Requiring publication in journals that meet Research Council ‘standards’ for Open Access.” — this will not be enforced.
- “No support for publisher embargoes of longer than six months from the date of publication (12 months for research funded by the Arts and Humanities Research Council (AHRC) and the Economic and Social Research Council (ESRC)).” — no, embargoes of up to 24 months allowed even in the sciences.
Can anyone doubt that the nobbling of a truly progressive policy was the result of lobbying by a truly regressive publishing industry? It’s been a tragedy to watch this policy erode away from something dramatic to almost nothing. Once more, it’s publishers versus everyone else.
Again, I have to ask this very simple question: why do we tolerate the obvious conflict of interest in allowing publishers to have any say at all in deciding how our government spends public money on publication services?