So I had cause to revisit Acrocanthosaurus over the last weekend; that means that the promised Peck's Rex revision is yet to come to fruition, but you can enjoy some non-tyrannosaur-larger-theropod goodness anyways: [link]

My original acro skeletal was done about a decade ago, with a quick revisit in 2003 to change the limbs to the modern inward-facing palm position (this was the version that was available on the web). It held up reasonably well, the proportions were fine, etc. The largest problem was I had restored the dorsal neural spines after the BHI reconstruction of "Fran" NCSM 14345, which by their own admission was excessive - none of the neural spines were complete in the dorsal region, so they made them as impressive-looking as possible.

Now I've gone back and set them at a more conservative height, and one that is more in line with the other specimens. I also updated the forelimbs after the work of Senter & Robbins (2005), as I'd protracted the humerus too far back in 2003.

That's it, pretty minor, but since I had to do the work anyways I figured I'd share it here on DA.

-Scott

As advertised, here is Stan: [link]

As I changed the copyright information I noted that it was last updated in 2004. What happened the last five years?

Both less and more than with Sue. I was able to measure Stan directly, so most of the individual measurements didn't change much, with one large exception: the head.

After I took my measurements (not surprisingly of the cast that resides at the Wyoming Dinosaur Center) I lost some of my notes (paper is such a tenuous medium) so I had a colleague remeasure the skull for me. In a unit-error conundrum similar to the famous Lockheed/NASA mistake that sent a Mars probe hurtling to its fiery death (but a lot less expensive!) centimeters and inches were transposed and I ended up scaling the skull too small.

If you've ever seen a mount of Stan in person, you probably noticed that the head looks disproportionately large, while I had it proportionately small relative to other specimens of T. rex. This was noted a couple years ago (by more than one person) so I've had the correct measurement for a while. By that time I'd identified some other questions (skull articulation, cervical series articulation, etc.), and with T. rex not very high on my priority list at the time, it didn't get taken care of.

So now it's fixed. So is the position of the cervicals (which reflect their actual articulation, rather than that of AMNH 5027). Also, in the last two ears the people at BHI had all of the skull bones scanned into a computer, and reconstructions that take into account postmortem distortion have been trickling out. As a result the famous upward kink to the snout is no longer there (it was the result of squishing) as well as some other, less obvious changes.

Also, no pectoral girdle remains were found with Stan. I had scaled the shoulder blades a bit smaller than predicted in 2004 (it went well with the small head..!) but have now restored the chest to the full predicted length (via ratios with with femur). Of course I also took the opportunity to update the forelimbs to reflect current data (as with Sue).

And that's about it. The limbs and tail may look like they're different in size, but that's only relative to the skull and chest alterations. Almost nothing else had to be changed, yet the cumulative effect is quite radical if you look at the old and new ones together.

Coming up next will be Peck's Rex. Give me a week or two (more little changes have to be made, as with Sue).

-Scott

Here is the first piece of tyrannosaur goodness: [link]

If you like, you can compare it to the rigorous version that still adorns my skeletaldrawing.com gallery here: [link]


So what's changed? First a bit of personal history as relates to this specimen. I first restored Sue back in 2000, when it was first mounted in Chicago. I worked from nothing but a photo, and I am thankful that my initial attempt was not widely distributed. It was an important lesson in the pitfalls of working from photographs.

In 2002 the Brochu monograph was published by SVP, simultaneously showing me how wrong-headed my original approach was and providing an opportunity to improve my technique. That version was essentially what you can see on the webpage.

That was one of the first skeletal drawings I did in Photoshop, and parts were hand-drawn and scanned in, while others were done de novo in Photoshop. I also (as a short cut) scaled some items by using the scale bars in the publication, a technique I don't recommend after a few years of learning the hard way that most publications have scale bars that are not totally accurate.

So I have now reworked Sue from scratch. I have also followed the excellent morph work of Lipkin & Carpenter on the position of T. rex forelimbs. While I don't agree with all of their behavioral interpretations, their descriptive morph is spot on.

The result is a slightly more robust, and dare I say "real" feeling animal. The proportions aren't radically different from my 2002 attempt, but any changes I made better reflect the actual specimen.

Of interest is that the neck of Sue (and Peck's Rex...more on that later) is curved into a tighter "S-curve" than I had originally illustated. It's a bit different from the classic AMNH specimen (5027) and I'm unsure if that is do to individual variation, or if the original monograph has some errors. I will keep you posted as I find out.

Coming up next will be a rework of BHI 3033 ("Stan") and then Peck's Rex (MOR 980) which is not quite as large as I originally illustrated.

Let me know if these types of updates are of use/interest to visitors; if so I will try to provide more in depth coverage of new skeletal reconstructions as I post them.

- Scott

So...I don't actually love T. rex. Don't get me wrong, it's a cool animal, but I've had to devote waaaay too much of my time to the critter over the last decade, so in general I've avoided doing additional work on it unless someone needed it specifically (i.e. if someone paid me).

That said, several minor errors or scaling issues have come to my attention the last couple years (e.g. when I was asked to restore the "Peck's Rex" specimen much of it was being molded, so I had to rely on some second-hand measurements) and I've decided it's high time to update the whole series. AMNH 5027 and the Carnegie specimen are fine, but Sue, Stan, and Mr. Peck's all have revisions incoming.

So if you're just dying to do an illustration based on them, wait a little longer please.

- Scott