I didn't get a chance to see last night's Jurassic Fight Club (you can see my thoughts on the first episode here) but someone has put the "main event" up on the web. I don't know whether to laugh or cry;
I know I promised to try to be more even-handed in reviewing science media but there are some real howlers in that clip. First is that it has yet to be conclusively established that Nanotyrannus was an actual distinct genus of tyrannosaurid; the fossils attributed to the "pygmy tyrant" may just be young Tyrannosaurus. The debate is ongoing, and I hope that this point was made in the show. Still, I found it strange that Nanotyrannus was asserted to be a Tyrannosaurus hunter, deliberately sniffing out and killing young Tyrannosaurus. To the best of my knowledge there's no evidence for this, and finding a young Tyrannosaurus skeleton with teeth ascribed to Nanotyrannus would have to be provided before such an idea could gain support.
The presence of a narrow-snouted Nanotyrannus is made even worse by the fact that the baby Tryannosaurus look like miniature adults, however. Fossils of young Tyrannosaurus have shown this is not the case, and juveniles looking distinctly different from adult individuals. This can be seen in other tyrannosaurs, as well, like the juvenile Tarbosaurus I wrote about last week. (Added to all this irritation is the use of terms like "tyrannosauruses." It might make me a pedant but it's a little grating to hear genus names misused in such a way.)
The second thing that popped out at me was the claim that the young Tyrannosaurus would have had a "septic bite," their mouths full of bacteria because their arms were too short to brush their teeth of all the rotting flesh left in their mouths. If this was true of Tyrannosaurus it would have been true for many, many other predatory dinosaurs and there's no reason to suggest that it was a special "weapon" that they specifically used to defend themselves with.
Third, if you take a look at the plate tectonic map near the beginning of the clip you'll see that the continents are all in modern form and simply shift around. This is not what actually happened (where the heck is the Western Interior Seaway?). It might be another minor thing but it if you're going to take the time to do something you might as well do it right. I recognized that JFC is not NOVA or Nature but it seems that the shows are created with a particular story set in place and pieces of existing evidence are picked out to match the idea. The show definitely could have benefited from some more technical input; there's no reason that it can't be entertaining and accurate.
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To be fair, the episode did spend a good deal of time on whether nanotyrannus is a separate genus or a juvenile tyrannosaurus, but ultimately declared it a separate genus for the purpose of this show.
I recorded both the Majungatholus episode and this new one last night. I intend to watch them both and blog on their quality. I am not expecting great things.
I believe the "sir william" juvenile Tyrannosaurus specimen was supposed to have been found with a) tyrannosaur bite marks and b) isolated "Nannotyrannus" teeth, I'm assuming this provided the inspiration for the show (which I haven't seen.)
As far as I know a taphonomic study of "Sir William" hasn't been published. The "septic bite" claim gets thrown around so much it would be interesting to try and test it. Do Varanus bites leave osteological evidence of infection?
What does the latest work on infant and juvenile tyrannosaur appearance tell us?
Should that be "to the best of my knowledge there's no evidence for this"?
Yeah, my hed asplode too. With regards to the status of Nano-T: they fights were all plotted and being animated by the time the interviews with the talking heads took place, so I think George was honestly surprised to find out that not everyone is convinced that it is anything other than a juvenile T. rex.
As for juvenile T. rex: at present there are no definite T. rex individuals as young or younger than the specimens some call Nanotyrannus (except the very imcomplete 2 year old at LACM), while there are no adult "Nanotyrannus" specimens. Make of that what you will.
Thanks for the comments and corrections, everyone.
Although I have commented a lot about my doubts about Nanotyrannus I think the debate over it a fascinating and I definitely want to know more. Hopefully some more work will be done (like what "Thomas" at the Los Angeles museum might tell us) and the "Jane" volume will be published soon.
I remember reading Gregory Paul's arguments in favor of running tyrannosaurs in Predatory Dinosaurs of the World. There's been a lot of biomechanics done since then... When they showed the shots of grown Tyrannosaurs with both feet off the ground -- you know, running! -- I think I made a small involuntary noise indicating disbelief.
The tails seem too flexible to me; on the other hand, I always think that, based on my limited experiences in handling reptiles.
Something I forgot to mention in my comment on the Majungotholus episode -- they show a great deal of (forgive me if I'm using the wrong terminology here -- autodidact at work) lateral flexibility in the pelvis. They sprawl and straddle. They look like chickens. On the other hand, maybe that's accurate.
I found the discussion of Nanotyrannus to be the high point of the show. I wish there'd been an opportunity for Messrs. Currie, Holtz (to whom a tip of the hat -- I'm enjoying the dickens out of your encyclopedia), & Co. to respond to each other's arguments.
The questions left in my mind were whether the specific anatomical details (specifically tooth structure and brain/head orientation) that distinguish Tyrannosaurus from Nanotyrannus are the kinds of things that could change as the animal matured, and if so how do these features reflect the differences in lifestyle between immature and mature Tyrannosaurs?
They did devote a fair amount of time to the nano-t species issue. They based their decision that nano-t was a separate species because of a a few significant differences.
1)Tooth shape - TRex have almost conical teeth, NanoT have blade like teeth.
2)Tooth number - the number of teeth in the lower jaw of TRex and NanoT is significantly different.
3)Head/Jaw shape/structure - NanoT had an elongated head
4)Leg bone ratios - NanoT appears to have had longer legs.
5)Brain shape - differences in braincase structure.
6)Inner ear canal area - NanoT would have held it's head at more of an angle than TRex.
I'm not saying all these are true, but that's what the show put forth. All that combined pointed to a separate species of dinosaur. They based the NanoT as a TRex hunter theory on a juvenile TRex find that had markings on the bones that didn't match what they see in TRex attack evidence, but it did match NanoT teeth in number and markings.
The hypothesis of the septic bite was based on looking at tooth and jaw structures they seemed to imply that were unique to TRex that were very similar to Komodo Dragon structures.
Again, I'm not saying I know any of this to be 100% accurate, I'm just clarifying what the show said.
Since the producers of JFC decided ab initio that they were using Nanotyrannus as a valid taxon, they obviously kept most of the interviews that emphasized the differences. As I admitted in my interview some of the internal features (pneumatic chambers and the semicircular canal issue) *might* make the case, but it is not like these cannot change with ontogeny either!
As for the other "differences" they showed: given we do not have juvenile T. rex skeletons is Nanotyrannus is valid, then there is no basis for the argument that juvenile T. rex had different tooth shape, tooth number, head shape, leg ratio, or brain shape than did Nanotyrannus.
The leg ratio issue REALLY pissed me off, actually!! Currie (who is definitely pro-Nano) demonstrated in a paper a few years ago that limb allometry in tyrannosaurines and albertosaurines are pretty conservative, so a juvenile T. rex the same size as Nanotyrannus would have essentially the same limb proportions. Regardless of the issue of NanoT, you can't ignore allometry. (Or rather you can, but you abandon what we know about science in the process...)
And next week: featherless Deinonychus with broken wrists...
I dislike maps showing modern continents moving around to represent tectonics. Even the better quality representations still seem iffy to me, once they go further than the miocene.
Who cares if the show has faults (Walking with Dinosaurs & company had too),at least for me it's entertaining...I saw the T.rex vs Nano-T fight just a couple of minutes ago on youtube and i really liked it,even if somewhat unrealistic (the Nano would have ran away when the female T.rex appeared).
As i said in the past...Dinosaurs tearing eachother apart;there's something cooler than that? ;)