Friday, December 18, 2009

Dinosaur Roud-up 6


Tawa hallae: New Meat-Eating Dinosaur Alters Evolutionary Tree

Yeah, this update is courtesy of Dr. Michael Ryan in Pittsburgh (whom we visited, but he was out digging up dinosaurs while we were Pennsylvania).

Looks pretty bad-ass, right? The paper that describes this animal says:

Characterizing the evolutionary history of early dinosaurs is central to understanding their rise and diversification in the Late Triassic. However, fossils from basal lineages are rare. A new theropod dinosaur from New Mexico is a representative of the early North American diversification. Known from several nearly complete skeletons, it reveals a mosaic of plesiomorphic and derived features that clarify early saurischian dinosaur evolution and provide evidence for the antiquity of novel avian character systems including skeletal pneumaticity. The taxon further reveals latitudinal differences among saurischian assemblages during the Late Triassic, demonstrates that the theropod fauna from the Late Triassic of North America was not endemic, and suggests that intercontinental dispersal was prevalent during this time.

Dr. Ryan elaborates:
One of Tawa’s most important contributions to science has to do with what it says about Herrerasaurus, an unusual theropod placed either just outside or just inside the evolutionary tree of theropods.

Tawa has a mix of Herrerasaurus-like characteristics (for example, in the pelvis) and features found in firmly established theropod dinosaurs (for example, pockets for airsacs in the backbone). Therefore, the characteristics that Herrerasaurus shares uniquely with theropods such as Tawa confirm the characteristics didn’t arise independently and that Herrerasaurus is indeed a theropod.

The firm placement of Herrerasaurus within the theropod lineage suggests that once dinosaurs appeared, they very rapidly diversified into the three main dinosaur lineages that persisted for more than 170 million years.


Awesome.

Yet, there are more important values to the Tawa than its age

Other important items from "Archosaur Musings":

The thing that interested me was the evidence for pneumatisation of parts of the skeleton (hence the awful pun in the title of this post). Those who keep up with the excellent SV-POW (or even the occasional comments on here on the subject) will know that a variety of archosaurs have (or rather had in the case of the extinct ones) extensions of the lungs called air sacs that sat alongside or invaded various bones of the skeleton. Of obvious note are the birds, pterosaurs and sauropods, but actually most theropods show at least some pneumaticy (though some, like Areosteon, more than others).

The relevant point here is [my emphasis] that although there is some evidence to suggest that all archosaurs had at least some minor pneumaticy early on in their evolution, there remains the strong possibility that the pterosaurs, sauropods and theropods all gained their pneumaticy independently. The fossil evidence is rather ambivalent. While the idea that theropods and saruopods are very closely related is hardly troubled by the possibility that they did not inherit pneumatic bones from their saurischian ancestors, it does seem a little odd and of course causes a few problems for the ‘pterosaurs-as-ornithodirans’ idea.

Happily, while not exactly solving this, Tawa does provide some new information here. In addition to being an especially basal theropod, Tawa does have pleurocoels on some of its vertebrae – they are pneumatic (and there are pneumatic invasions in parts of the skull too). The new information that Tawa brings to the table also appears to help resolve some phylogenetic questions about early theropods and other saurischians, and another early and pneumatic theropod, Chindesaurus, can now be positioned with more confidence.

Between the two this provides quite a high level of confidence that pneumaticy was around at least in the very earliest theropods and thus closes the gap between the later pneumatic theropods and the sauropods and pterosaurs. In other words while there is still no perfect continuum of pneumatic taxa between the groups, the gap has been shrunk with this new find.

See? That's much more interesting than it simply being very old! right?

Clash of the Dinosaurs review
The Discovery Channel's new mini-series Clash of the Dinosaurs is not receiving high praise from academics - which is disappointing. Not surprisingly, there are many people (some paleontologists, even) who are speaking up about their distaste for the series.

Me, I'll make comments with regularity on the deplorable state of "science journalism" where basically, someone who knows nothing about dinosaurs writes absolute nonsense and ends up embarrassing themselves.

Well, I'm no paleontologist, so I can only imagine how upset they must get when this happens. Actually, here is someone who was actually interviewed to be on the Clash of the Dinosaurs, and is more upset with the finished project than you could imagine!

Lies, Damned Lies, and Clash of the Dinosaurs
To begin, this website is run by three paleontologists who dedicate much of their academic pigeon-holing to sauropods. One of these men was used as an expert for the science in Clash of the Dinosaurs. MATHEW JOHN WEDEL from the Department of Anatomy and College of Podiatric Medicine atWestern University of Health Sciences in Pomona, California, got his big chance to be on TV and be a part of a cool-sounding show all at once - sounded too good to be true, and it was.

At this link you can view his initial impression in whole - which is worth reading, I promise you. Imagine having such high hopes, and then realizing you'd trusted manipulative fools with your reputation. Truly discouraging.

Says Wedel:

I need to preface what follows by saying that I thought the other talking heads did a great job. My experience suggests that the scientific problems with the series didn’t originate with the scientists, infrasound weapons excepted. Tom Holtz–another of the talking heads, and a good one–nailed it on the DML:

For those going to watch the show, a warning:
The documentarians often take anything that any of the talking heads speculated about, and transformed these into declarative statements of fact. In some cases this is particularly egregious, because I strongly disagree with some of these statements and believe the facts are against some of these (say, about tyrannosaurid cranial kinesis…) and they present these as facts rather than suppositions.

His thoughts were intentionally misconstrued by the producers at Dangerous Ltd and now he's unhappy about it.

No doubt, Dr. Wedel contacted Dangerous Ltd to get an explanation - and without receiving an adequate apology/retraction of the material in the episode he disliked so much, he's published his action plan against them.

I’m going to write back to Dangerous Ltd and request a copy of the release that I signed, to see what legal rights, if any, I may have to get this fixed. What would fixing it entail? Simple: I don’t care if they leave in the bit where they discuss the “second brain”, just cut out my speaking part. It’s probably all of ten seconds. They could even replace it with something or someone else, I don’t care. Just stop making me lie. I’d prefer to see that edited version replace the one currently in circulation, both for future broadcasts and for the DVD/Blu-ray release.

If they could fix my name while they’re at it, that would be nice, but it’s really small potatoes. “Matthew” Wedel is a dumb error, but it’s just an error. What they did in the ’second brain’ segment is a lie, and one that is corrosive to my public credibility.

I'm following along to see how this goes - things like this should cost a producer their job, but we'll have to wait and see. The motto of the story is: don't piss of paleontologists.

* Update: "Great news! I just got off the phone with someone at the Discovery Channel. He asked not to be named, but he has responsibility for Clash of the Dinosaurs and the authority to do what he promised, which is to fix the “second brain” segment exactly as I asked in the previous post! He said that the program would not be broadcast again until that segment was fixed, and that the fixed version would be in the DVD/Blu-ray release," said Wedel.

Later in the post, Wedel explains exactly how something like this happens. Basically, it's for entertainment purposes rather than scientific exposition, regrettably. Also, that link provides an excellent exposition of the behind-the-scenes stuff that goes into making these documentaries. A good read.

More venom towards the Clash

Turns out, allot of people were unimpressed with the show:
Sunday night, I watched Clash of the Dinosaurs, the show which I totally acknowledged to be a very bad show to watch. Not because of the animation which was incredible and well made, but because of the bad science behind it and the constant repetitious showing of dinosaur footage again and again and again. In fact this show is just as bad as the creationist films shown at Ken Ham's stupid crackhouse. Come to think of it, CotD is among the many science shows that's adding fuel to the creationists' efforts to find fault with everything science including dinosaurs.

Like creationists, the show is chock load of bad science and made up claims about certain dinosaurs and one pterosaur such as Quetzalcolatlus having eyes like a hawk that allows it to see from far distance (when no such evidence has ever been found!) and Sauroposeidon having a "second brain" despite the fact that the claim about the so-called second brain has long been clearly debunked.

[More hate for the show] here
Dinosaur Sunday: Good + Bad + Ugly from DinoGoss

and here
Clash of the Dinosaur TV Specials - From The Paleo King
Yikes. Guess they'll try better next time.

No comments: