Garth’s posterous

Bent in a kinda straight way 
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Stephen Fry observes a modern coelurosaur mating ritual

I basically pinched the title from an email sent to the Dinosaur Mailing List by Dr Thomas Holtz from the University of Maryland.

In cladistic terms birds are simply highly derived coelurosaurian dinosaurs. (Though of couse it depends where you want to draw your line. They - and us - just as legitimately could be described as highly derived sarcopterygian fish. I suppose it depends which common ancestor you are more keen on.)

Follow the link and watch the video.

Fry finds 'funniest ever' mating ritual

When Stephen Fry goes in search of the rare kakapo - "the old night parrot of New Zealand" - he finds himself privy to an unusual mating ritual which is "one of the funniest things he has ever seen".

Fry and zoologist Mark Carwardine have been tracking down some of the most endangered animals on the planet in a six-part series.

Last Chance to See goes in search of the Kakapo on Sunday 4 October at 2000BST on BBC Two.

Previous episodes are available at the Last Chance to See website.

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Filed under  //   coelurosaurs   dinosaurs   evolution   kakapo   natural history   Stephen Fry  

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Raptorex, the new tiny tyrant

Weighing only a fraction as much as Tyrannosaurus rex, the 125 million-year-old Raptorex nevertheless exhibits a similar body plan in this artwork depicting both species.

Who would have thought Tyrannosaurus rex had such a murderous "mini-me" in its family tree?

Not Stephen Brusatte, a paleontologist at the American Museum of Natural History. "This was completely unexpected," he said.

And not University of Chicago paleontologist Paul Sereno, who along with Brusatte and other colleagues figured out that the tiny tyrannosauroid had virtually all the lethal weapons brandished tens of millions of years later by a behemoth 90 times more massive.

"From the teeth to the enlarged olfactory bulbs, the enlarged jaw muscles, the enlarged head, the small forelimbs, the lanky, running, long hindlimbs with thick-pressed foot for hunting prey - we see this all, to our great surprise, in an animal that is basically the body weight of a human," he told reporters.

The 125 million-year-old fossil dinosaur, unearthed in China and dubbed Raptorex kriegsteini, is "as close to the proverbial missing link on a lineage as we might ever get for tyrannosaurs," Sereno said.

The researchers laid out their conclusions in a paper published online today by the journal Science.

More reports:

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Filed under  //   archosaurs   dinosaurs   evolution   palaeontolgy   Raptorex kriegsteini  

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Pot-Bellied Dinosaur Skeleton Found in Utah

The kind of dumbed-down science writing I hate, but that's the world we live in these days apparently.

But still, anything about therizinosaurs is welcome in my view.
The most complete skeleton of a type of pot-bellied dinosaur, a therizinosaur, has been discovered in southern Utah.

Such remains shed light on the evolution of leafy and meaty diets back in paleo times, suggesting that iconic predators like Velociraptor may have evolved from less fearsome plant-eating ancestors.

The http://www.livescience.com/php/multimedia/imagedisplay/img_display.php?s=animals&c=news&l=on&pic=090714-nothronychus-02.jpg&cap=Nothronychus+graffami+shown+foraging+in+a+mangrove+forest+near+the+shoreline+93+million+years+ago.+A+bull+Zuniceratops+is+passing+in+the+background.+Credit%3A+%A9+Victor+Leshyk+2009.&title=">newly discovered dinosaur, dubbed Nothronychus graffami, lived some 93 million years ago. When alive, the animal would have stood at 13 feet (4 meters) and sported a beaked mouth and forelimbs tipped with 9 inch- (22 cm)-long http://www.livescience.com/php/multimedia/imagedisplay/img_display.php?s=animals&c=news&l=on&pic=090714-dinosaur-claw-02.jpg&cap=The+gigantic+claws+on+the+%22hands%22+of+Nothronychus+graffami+likely+helped+the+dinosaur+grasp+tree+branches+to+find+leafy+snacks.+The+claws+also+may+have+served+to+intimidate+predators+and+as+display+for+wooing+mates.+Credit%3A+David+D.+Gillette.&title=">sickle claws.

Its stumpy legs, large gut and other features suggest the lumbering giant scarfed down plants rather than chasing after meaty prey.

Article here

This is the second species assigned to the genus Nothronychus.

The genus even has its own YouTube tribute!

Very interesting to see the range of ideas these days about how to depict what dinosaurs may have looked like.

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Filed under  //   biology   dinosaurs   evolution   Nothronychus graffami   therizinosaurs  

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Limusaurus – an herbivorous ceratosaur?

Limu spec
 
limu skel
 
This is a bit different! I hadn't picked up on this in the previous piece I posted. I'd just assumed it was another coelurosaur.
 
As Archosaur Musings notes, while not unsurprising that a number of theropods became herbivores, it is surprising "...that Limusaurus is a ceratosaur and thus part of a clade which would normally not be associated with this kind of lifestyle at all – at least the others are consistent. Ceratosaurs such as the eponymous Ceratosaurus, bizarre Carnotaurus and Abelisaurus while obviously having their differences do have one thing in common, namely being tanking great animal with shredding carnivorous teeth. Because, well, they killed and ate their dinner and it had a tendency towards a) being alive, and thus unlike plants, b) could run away."
 
Also interesting that this critter apparently dates from the middle Jurassic and thus, given that it already shows a number of seeming adaptations to herbivory, must have had a number of herbivorous and omnivorous antecedents. This pushes herbivory much further back in time for Theropoda, and I suppose phylogenetically as well.
 
That "...a basal member of a basal clade of theropods adopted herbivory far earlier than we thought."
 
Much more at the Archosaur Musings link.
 

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Filed under  //   ceratosurs   dinosaurs   evolution   finger homology   herbivory   Limusaurus inextricabilis   theropods  

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Beaked, Bird-like Dinosaur Tells Story of Finger Evolution

This image shows a reconstruction of Limusaurus with no evidence of feather structures.
This image shows a reconstruction of Limusaurus
 
Introducing Limusaurus inextricabilis ("mire lizard who could not escape").
 
June 17, 2009
Scientists have discovered a unique beaked, plant-eating dinosaur in China. The finding, they say, demonstrates that theropod, or bird-footed, dinosaurs were more ecologically diverse in the Jurassic period than previously thought, and offers important evidence about how the three-fingered hand of birds evolved from the hand of dinosaurs.
 
The discovery is reported in a paper published in this week's edition of the journal Nature.
 
"This work on dinosaurs provides a whole new perspective on the evolution of bird manual digits," said H. Richard Lane, program director in the National Science Foundation (NSF)'s Division of Earth Sciences, which funded the research.
 
Full article here.
 

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Filed under  //   birds   dinosaurs   evolution   finger homology   Jurassic   Limusaurus inextricabilis   theropods  

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Evidence birds did not evolve from dinosaurs?

 
I don't think so.
 
John Ruben is a well known BANDit. BAND = birds are not dinosaurs. This is allied to ABSRD (pronounced "absurd"), or anything but a small running dinosaur.
 
Membership of these groups is comprised of people who "know" that birds could not have evolved from dinosaurs, and are on a ceaseless quest to try and find evidence to support this "knowledge."
 
They "know" that feathers had to have evolved for flight directly and that flight evolved from the trees down, not the ground up.
 
But these are a priori beliefs, not facts established by evidence.
 
They are also a salutary lesson that clever and well educated people, experts in their own way and in their own fields, can also be very wrong about things and almost wilfully so.
 
On any reckoning of the available evidence, the case that birds are highly derived theropod dinosaurs is overwhelming. (Theropods were the two-legged carnivorous dinosaurs. A group ranging from the immense T rex to the tiny microraptor.)
 
It is now absolutely clear that feathers did evolve in the context of becoming volent, but were exapted for that purpose. Exaptation is where a character that originally fulfilled another function is put to another use.
 
While we can never be certain about these things, (the Deep Time problem makes this impossible), it does seem that primitive filamentous feathers, akin (but probably not exactly the same) to those found on Kiwis evolved with the Theropoda long before the first theropod became the first bird, and probably for the purpose of insulation.
 
We now have numerous fossils of what are clearly dinosaurs covered in this "dino-fuzz." But even more astounding, (and how the BANDits reconcile this with their views is simply beyond me), we have many fossils now of again unequivocal dinosaurs not only covered in this fuzz, but also with modern looking feathers adorning their arms and tails. Other than being symmetrical rather than asymmetrical (for those on the arms), they are identical to the flight and body feathers found on modern birds.
 
Now, these are mostly maniraptorans. Velociraptor was such a creature, as was oviraptosaurus and its kin.
 
However, one of the very first of the animals discovered in China covered in dino-fuzz, Sinosauropteryx prima, was not a maniraptoran.
 
It was a primitive compsognathid dinosaur. A "living fossil," (yes I know the term is very suspect, but you get my drift), even in its own day. This would indicate that feathers or their antecedents evolved much earlier on and further back along the dinosaur family tree than people had previously imagined, and that such structures were widespread amongst several lineages within the Theropoda.
 
You really would think that this would close the case on this question. But never underestimate people's ability to believe what they want to believe and build elaborate houses of cards to support it.
 
It's not just UFO enthusiasts or 9/11 conspiracy cranks who do this.
 
So the BANDits start looking further back in time to search for any poorly preserved reptile that has some vaguely avian characteristic which they then cite as a possible contender as an ancestor to birds. And at times by vague, I really do mean vague. A somewhat triangular skull is put forward as indicating possible avian affinities.
 
That some of these reptiles don't appear to be anywhere near to the archosaurs, the group of diapsid reptiles that birds, (along with crocodilians and dinosaurs), clearly belong to, doesn't seem to faze them.
 
That they can't give a plausible evolutionary line from said primitive reptile to birds supported by any fossil evidence, doesn't seem to faze then either. The argument runs something like this - "this Triassic reptile has some vague similarity to modern birds and somehow, we don't know how though, may have given rise to them.
 
"We just know however that birds didn't evolve from theropod dinosaurs and therefore something like this must have been the ancestor."
 
Not a particularly strong argument I'd suggest.
 
Here are some artists' interpretation of the modern understanding of maniraptoran dinosaurs, oviraptosaurs in this case:
 
 
 
These are dinosaurs.
 

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Filed under  //   ABSRD   BAND   BANDit   birds   Deep Time   dino-fuzz   dinosaurs   evolution   feathers   John Ruben   maniraptorans   science   Sinosauropteryx prima   thecodont hypothesis  

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Land Of Improbable Dinosaur Pee

National Geographic asked Dr Thomas Holtz, a dinosaur paleontologist at the University of Maryland’s Department of Geology, to give a professional's reaction to Will Ferrell's new film Land of the Lost.

It includes this explanation as to why you could not douse yourself in dinosaur urine, even if that was your thing:

For example?

[He] assumes that if he douses himself in hadrosaur urine …

And a hadrosaur is?

A duck-billed, plant-eating dinosaur.

Now, back to the urine.

He assumes that dousing himself will keep the predators from going after him. Everyone else would think the urine would attract the predators, which it does. They sniff him out easily. It’s a good gag, but the premise isn’t based on biology.

How so?

Dinosaurs wouldn’t pee lots and lots and lots of urine. They’re part of this group of reptiles called diapsids. Today’s diapsids are lizards, snakes, crocodiles, and birds. The way they get rid of nitrogenous wastes from their kidneys is not by peeing lots of liquid. It’s by excreting this white sticky paste. So when you find the white paste on your car, the bird hasn’t pooped on it; it’s peed on it. That way they conserve a lot more liquid than mammals or amphibians.

The pee mistake has been made before?

Even Walking with Dinosaurs got this infamously wrong. In one scene in this 1999 BBC documentary, a big predator marked its territory by peeing all over it. Mammals do that because we pee a lot. Reptiles wouldn’t.

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Filed under  //   amphibians   diapsids   dinosaurs   Dr Thomas Holtz   evolution   films   hadrosaurs   Land of the Lost   mammals   nitrogenous waste   palaeontolgy   reptiles   urine   Walking with Dinosaurs  

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First definitive carcharodontosaurid from Asia

shaochilonglowres1

Shaochilong maxilla (top), braincase (middle) and skull roof (bottom) from Brusatte et al., 2009.

 

"While in Beijing I figured I should try to see the specimen, as some authors had suggested that it was a tyrannosauroid or a basal coelurosaur of some kind. Either way, it would provide important data for my thesis. But when I opened the drawer and saw the maxilla and braincase staring back at me, I quickly realized something was wrong. “C.maortuensis is not a coelurosaur, but possesses a number of unique features seen in Carchrodontosaurus, Giganotosaurus, Mapusaurus, and Acrocanthosaurus—colossal theropods closely related to Allosaurus that are grouped within their own subclade, the Carcharodontosauridae (the shark-toothed reptiles, named for obvious reasons)."

The new name given to this animal, Shaochilong, "meaning “shark teeth dragon” in Chinese, [is an] obvious reference to the carcharodontosaurids."

Brusatte, S., Benson, R., Chure, D., Xu, X., Sullivan, C., & Hone, D.(2009). The first definitive carcharodontosaurid (Dinosauria: Theropoda) from Asia and the delayed ascent of tyrannosaurids Naturwissenschaften DOI: 10.1007/s00114-009-0565-2

Abstract:  Little is known about the evolution of large-bodied theropod dinosaurs during the Early to mid Cretaceous in Asia. Prior to this time, Asia was home to an endemic fauna of basal tetanurans, whereas terminal Cretaceous ecosystems were dominated by tyrannosaurids, but the intervening 60 million years left a sparse fossil record. Here, we redescribe the enigmatic large-bodied Chilantaisaurus maortuensis from the Turonian of Inner Mongolia, China. We refer this species to a new genus, Shaochilong, and analyze its systematic affinities. Although Shaochilong has previously been allied with several disparate theropod groups (Megalosauridae, Allosauridae, Tyrannosauroidea, Maniraptora), we find strong support for a derived carcharodontosaurid placement. As such, Shaochilong is the first unequivocal Asian member of Carcharodontosauridae, which was once thought to be restricted to Gondwana. The discovery of an Asian carcharodontosaurid indicates that this clade was cosmopolitan in the Early to mid Cretaceous and that Asian large-bodied theropod faunas were no longer endemic at this time. It may also suggest that the ascent of tyrannosaurids into the large-bodied dinosaurian predator niche was a late event that occurred towards the end of the Cretaceous, between the Turonian and the Campanian.

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Filed under  //   carcharodontosaurids   dinosaurs   evolution   science   Shaochilong   theropods  

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