February 6, 2014
In a recent comment, Doug wrote:
If I want to be a truly educated observer of Tyrannosaurus rex mounts, what 5 things should I look for in a reconstruction to assess if it is true to our current scientific understanding? I’m not talking tail dragging/upright at this point…we are well past that I hope.
If he had asked about Apatosaurus, I could have written him a novel. But it is a point of pride with me not to contribute to the over-application of human attention to T. rex; not only would it be vulgar, it would also be a waste of resources, considering how many people already have that covered. So, you theropod workers and avocational “rexperts”, we’re finally inviting you to the high table. Please, tell us–and Doug–what separates the good T. rex mounts from the crappy ones. Big piles of SV-POW! bucks will be showered on whoever brings the most enlightenment, especially if you adhere to the requested List of 5 Things format.
The comment lines are open–go!
October 17, 2013
convincing genetic engineers that everyone would look better if they had sauropod tails.
If you have no idea what I’m on about, go check out XKCD.
June 30, 2013
Well, I’m back. Been on the road a lot–to Flagstaff for a few days around Memorial Day, and in Oklahoma to visit family in the first half of June. Now I’m busy with the summer anatomy course, but I finally found time to post some pictures.
One of my favorite museums in the world is the Museum of Osteology in Oklahoma City. It hits all the right notes for me: just shedloads of stuff on display, mounts you can walk all around and even touch (all they ask is that you don’t climb on them), and nary an interactive gizmo in sight. Plus a gift shop at the end where I could easily spend an hour (and several thousand dollars, if I had that much disposable dough and someplace to put all the loot). This was my second visit, but I never got around to posting the photos from my last visit, so maybe I can make up for that this summer. This post just has some highlights–I’ll try to get more photos up before another month goes by.
One of my favorite things in the museum is this awesome and appropriate triple display of the three-banded armadillo.
And old friend, from a new perspective.
In my experience, in the Great Plains states it is a rare museum indeed that does not have a two-headed calf. Not just natural history museums, either–historical museums and roadside attractions usually have at least one. The first I ever encountered was at the Dalton Gang Hideout in Meade, Kansas–maybe someone knows if it is still there? Even as a kid, I understood that the link between bovine developmental anomalies and Old West outlaws was pretty tenuous–basically, both crop up in Kansas–but I didn’t mind then and I don’t mind now. IMHO, finding two-headed calves on display in unexpected places only reinforces the concept of museums as cabinets of wonder.
Of course, it is entirely appropriate to find two-headed calves in an osteology museum, and the Museum of Osteology has more specimens than I’ve ever seen in one place.
The herp case is rad: the anaconda in the middle is a 14-footer, and the king cobra at lower right is 13’7″. And check out the super-fat Gaboon viper below the anaconda. If you’re wondering about turtles and crocs, they’re in the next case over.
As anyone who followed Darren’s multi-part series on matamatas (1, 2, 3, 4, 5) knows, they are fabulously weird. As I conceive it, there are two kinds of turtles: matamatas, and “regular-ass turtles”, the latter being the paraphyletic group that includes all non-matamata turtles.
My favorite mounts in the Museum of Osteology are the smallest: a pair of impossibly tiny ruby-throated hummingbirds.
I spend a lot of time with vertebrate bodies and skeletons, both taking them apart and putting them back together, and I am not exaggerating when I say that these are the most astonishing skeletal mounts I have ever seen. Unfortunately there aren’t any external indicators of scale with these skeletons, and perspective effects would defeat any attempt to put a scale bar up against the glass. These ruby-throated hummingbirds are slightly longer-billed than the Anna’s hummingbird mentioned in this post, but even so the skulls are probably no more than 30mm long. I recently helped London clean up a rat skull (yet another thing I need to blog about), and that skull was about as big as one of these skeletons minus the bill.
That’s all for now. If you’re ever in Oklahoma City, go check out the Museum of Osteology. I recommend it to anyone who is interested in bones, anatomy, animals, nature, or even, like, things.
April 20, 2013
It’s well worth reading this story about Thomas Herndon, a graduate student who as part of his training set out to replicate a well-known study in his field.
The work he chose, Growth in a Time of Debt by Reinhart and Rogoff, claims to show that “median growth rates for countries with public debt over roughly 90 percent of GDP are about one percent lower than otherwise; average (mean) growth rates are several percent lower.” It has been influential in guiding the economic policy of several countries, reaffirming an austerity-based approach.
So here is Lesson zero, for policy makers: correllation is not causation.
To skip ahead to the punchline, it turned out that Reinhart and Rogoff made a trivial but important mechanical mistake in their working: they meant to average values from 19 rows of their spreadsheet, but got the formula wrong and missed out the last five. Those five included three countries which had experienced high growth while deep in debt, and which if included would have undermined the conclusions.
Therefore, Lesson one, for researchers: check your calculations. (Note to myself and Matt: when we revise the recently submitted Taylor and Wedel paper, we should be careful to check the SUM() and AVG() ranges in our own spreadsheet!)
Herndon was able to discover this mistake only because he repeatedly hassled the authors of the original study for the underlying data. He was ignored several times, but eventually one of the authors did send the spreadsheet. Which is just as well. But of course he should never have had to go chasing the authors for the spreadsheet because it should have been published alongside the paper.
Lesson two, for researchers: submit your data alongside the paper that uses it. (Note to myself and Matt: when we submit the revisions of that paper, submit the spreadsheets as supplementary files.)
Meanwhile, governments around the world were allowing policy to be influenced by the original paper without checking it — policies that affect the disposition of billions of pounds. Yet the paper only got its post-publication review because of an post-grad student’s exercise. That’s insane. It should be standard practice to have someone spend a day or two analysing a paper in detail before letting it have such a profound effect.
And so Lesson three, for policy makers: replicate studies before trusting them.
Ironically, this may be a case where the peer-review system inadvertently did actual harm. It seems that policy makers may have shared the widespread superstition that peer-reviewed publications are “authoritative”, or “quality stamped”, or “trustworthy”. That would certainly explain their allowing it to affect multi-billion-pound policies without further validation. [UPDATE: the paper wasn't peer-reviewed after all! See the comment below.]
Of course, anyone who’s actually been through peer-review a few times knows how hit-and-miss the process is. Only someone who’s never experienced it directly could retain blind faith in it. (In this respect, it’s a lot like cladistics.)
If a paper has successfully made it through peer-review, we should afford it a bit more respect than one that hasn’t. But that should never translate to blind trust.
In fact, let’s promote that to Lesson four: don’t blindly trust studies just because they’re peer-reviewed.
June 23, 2012
Here’s a cool skeleton of the South American pleurodire Podocnemis in the Yale Peabody Museum.
What’s that you’re hiding in your neck, Podocnemis?
Laminae! Here’s a closeup:
The laminae run from the transverse processes to the prezygapophyses and the centrum, which I reckon makes them analogues of the PRDLs and ACDLs of sauropods.
As long as I’m posting on Peabody turtles, here’s Archelon. It’s not bad, if you’re into that sort of thing. Which Mike clearly ain’t, but for a good reason, which will be revealed soon.
In the recent post on serial variation in sauropod cervicals, I wrote:
Even in ‘adult’ sauropods like the big mounted Apatosaurus and Diplodocus skeletons, the anterior cervicals are less complex than the posterior ones. Compared to posterior cervicals, anterior cervicals tend to have simpler pneumatic fossae and foramina, fewer laminae, and unsplit rather than bifid spines. In all of these things the anterior cervicals are similar to those of juveniles of the same taxa, and to those of adults of more basal taxa. This is also true in prosauropods–in Plateosaurus, the full complement of vertebral laminae is not present until about halfway down the neck.
I was working from memory there and actually understated things a bit. Plateosaurus presacral vertebrae don’t have well-developed spinal laminae, but they do eventually get the four major diapophyseal laminae–the anterior centrodiapophyseal lamina (ACDL), posterior centrodiapophyseal lamina (PCDL), prezygodiapophyseal lamina (PRDL), and postzygodiapophyseal lamina (PODL–please see the lamina tutorial if you need a refresher on these and the other 15 commonly identified laminae). But they aren’t all present halfway down the neck–the ACDL doesn’t really show up until the cervicodorsal transition. The other three kick in sequentially down the neck, as shown in the above image. I think that’s pretty cool, that you get different character states expressed at different points along the neck, in one individual organism, at one time. And possibly also at different times–in sauropods, the anterior cervicals tend to look more ‘juvenile’ or ‘primitive’, even in adult animals, so all of the cervicals go through a juvenile stage, but not all of them grow out of it. I don’t know if there’s a word for that–some kind of serial heterochronotopomorphy or the like–but hopefully someone will enlighten me.
I took the original photo in the collections at the Staatliches Museum für Naturkunde Stuttgart in the spring of 2004. Markus Moser and Rainer Schoch were wonderful hosts during my visit. Mike did all the work of turning the raw photo into a figure, so thanks to him for getting this off my hard drive and out into the world.