Mesozoic dinosaurs
tetrapodzoology | July 21, 2007
It isn't every day that your friends make the cover of Science magazine. Belated congrats to my friend Randy Irmis and his colleagues Sterling Nesbitt, Kevin Padian and others for their neat work on the dinosauromorph assemblage of Hayden Quarry, New Mexico (Irmis et al. 2007). Exciting stuff. Why? Well...
At Hayden Quarry, Norian-aged sediments of the Chinle Formation preserve temnospondyls, drepanosaurids, aetosaurs and diverse other crurotarsans, and dinosauromorphs. The big deal is this: despite the Late Triassic date of the assemblage, Irmis et al. (2007) have been able to demonstrate…
tetrapodzoology | July 18, 2007
Long-time blog readers will know that I am atrocious at keeping promises. And I will confess that part of the reason for titling an article 'Goodbye Tetrapod Zoology' was to cause a burst of panic, a rash of visitors (the strategy didn't really work: look at the counter... no spike on the graph). In seriousness, fear ye not oh followers, as I will indeed keep the blog ticking over, it's just that the only things I'll post will be short and sweet. And, unfortunately/fortunately, some bits of news come in that just demand a quick write-up...
Lurking in the Tet Zoo shadows are a number of…
tetrapodzoology | July 17, 2007
You all know that I'm just dying to publish those articles on biarmosuchians, dinocephalians and edaphosaurids, not to mention the dinoceratans, astrapotheres, pantodonts, pantolestans and nesophontids that I've been busy with lately. Then there are the stem-group monstersaurian lizards, the palaeophiids, the miniature ground sloths, the meiolaniids, the giant iguanas; and those long-overdue articles on Piltdown, de-hominization, knuckle-walking, amphisbaenians, tortoises, kinglets and (cough) Eotyrannus. The fact is, I just don't have the time. And time is such a problem right now...
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tetrapodzoology | June 14, 2007
The gigantic mystery coelurosaur alluded to here in one of the ornithomimosaur articles - yes, you heard it here first - has at last been published, and it is an immense long-legged oviraptorosaur, as big as a tyrannosaur. But it is just one of three fantastic new discoveries from the world of dinosaurs that, sorry, I just had to cover...
Every now and again in the world of Mesozoic palaeontology a new discovery comes from left field and slams you in the ribs; something so surprising and counter-intuitive that it would have made a good April Fool's joke were it not actually real.…
tetrapodzoology | June 5, 2007
When most people (and that includes palaeontologists and dinosaur specialists) think of Brachiosaurus, they think of the east African taxon B. brancai, named by Werner Janensch in 1914. But they shouldn't: the 'real' Brachiosaurus is B. altithorax from the Morrison Formation of Colorado [later reported from Utah, Wyoming and Oklahoma], named by Elmer Riggs in 1903. The two species are actually quite different, leading Greg Paul to coin a new name - Giraffatitan - for the African taxon. This photo, kindly provided by Dr Matt Wedel (aka Dr Vector), shows the mounted B. altithorax skeleton that…
tetrapodzoology | June 5, 2007
Today, a new picture by my good friend Mark Witton, shamelessly stolen from his flickr site. And, yes, it shows the Campanian ceratopsid Styracosaurus albertensis eating a theropod carcass. If you think that the idea of a bristly omnivorous ceratopsid is odd and requires some justification, I will direct you to Mark's accompanying essay. As he admits, he has - for sure - used artistic license... however, both the presence of bristles in these animals, and the possibility of omnivory, do have some reasonable basis to them. I will say no more. Must do horned dinosaurs on the blog some time (…
tetrapodzoology | May 26, 2007
Following a recent phone discussion with Dave Hone of Ask A Biologist, I'm going to try something really lame in a desperate effort to boost my number of hits. Shudder. I am going to start posting a new picture every day. Yes, every day. The pictures might be of anything, so long as they are within the Tet Zoo remit of course. This will not impact the number/quality/timing of those super-lengthy 'proper' posts you all visit for. So here we are with # 1. It features a dromaeosaur coughing up a pellet: a possibility suggested by the discovery of a regurgitalite in Cretaceous rocks from Russia…
tetrapodzoology | May 24, 2007
Same old story: Naish plans to blog on long-promised subjects, Naish gets distracted by cool new stuff, Naish ends up writing about cool new stuff and delaying long-promised subjects for even longer. Here, inspired by a paper I recently published with University of Bristol's Barbara Sánchez-Hernández and Mike Benton (Sánchez-Hernández et al. 2007), I've made a concerted effort to finish writing about the Mesozoic tetrapods of the Galve region of Teruel Province, NE Spain. In the previous post I covered crocodyliforms and pterosaurs. This time we get to the dinosaurs [adjacent image shows…
tetrapodzoology | May 20, 2007
Another one of those projects too-long-in-gestation has finally appeared and, unlike the others (e.g., the much-delayed British dinosaurs article), it's one that I haven't previously mentioned on the blog (I think). For the last couple of years I've been working, on the side as it were, with University of Bristol's Barbara Sánchez-Hernández and Mike Benton on the fossil vertebrates from the Galve region of Teruel Province, NE Spain. This is a really rich site, best known for its sauropods and mammals, and it's been the focus of much research since the 1950s. Our new paper - a large synthesis…
tetrapodzoology | April 27, 2007
So, on to more ornithomimosaurs, aka ostrich dinosaurs (part I here). This time, the ornithomimids: this is the ornithomimosaur clade that includes only the edentulous arctometatarsalian taxa. Yes, I said arctometatarsalian*. However, note that some authors have incorrectly regarded Ornithomimidae as synonymous with Ornithomimosauria... and one author has even included therizinosauroids and alvarezsaurids within Ornithomimosauria. For those who don't keep up to date with the phylogeny of non-avian theropods, character evidence indicates that ornithomimosaurs are stem-group coelurosaurs,…
tetrapodzoology | April 25, 2007
As events conspire, I again find myself unable to devote time to completing any new blog posts. That's a shame, as I'm desperate to finish and publish my article on the terrifying sex organs of male turtles (yes really: stay tuned). In desperation, I've opted to dig out and recycle some old text. If you like dinosaurs, you might be pleased...
We've seen before that - perhaps more than most scientist-authors - I've lost/wasted an unbelievable amount of time on projects that ultimately failed, or have yet to come to fruition. There was the taphonomy book, and there are a long string of…
tetrapodzoology | April 12, 2007
Yesterday the most remarkable thing happened. No, I have not been handed new DNA work on the Dufftown rabbit-headed cat, nor has the rest of Yaverlandia been found. An articulated azhdarchid has not been discovered on a Cretaceous savannah ashfield, nor have the islands of the SW Pacific yielded an assortment of ten new cursorial, durophagous and scansorial mekosuchine crocodiles. No, it's something far, far more significant than any of those things...
Ok, it's not. Regular readers will be aware of one of the biggest proverbial thorns in my side: that bloody review paper on the British…
tetrapodzoology | March 13, 2007
Predators don't just kill 'prey' species; they also kill other predators whenever given the chance. Lions kill hyenas and cheetahs, tigers kill dholes, dholes kill tigers, wolves kill bears, otters kill mink... dinosaurs kill dinosaurs...
For various reasons my early plan to produce a new blog post every day has fallen by the wayside, as well it might given that this would cause me to spend what 'computer time' I have doing blog writing and nothing else. So in the interests of churning out new material, I have for a while been recycling old texts wherever possible. Several years ago, Dave…
tetrapodzoology | March 11, 2007
Most of us have grown up with the idea that the Mesozoic Era was, excepting the Early Triassic, a time when dinosaurs dominated life on land. Or, put another way, a time when dinosaurs were the most ecologically significant and most obvious of all land animals. The familiar generalization, recounted in every book on Mesozoic life, is that dinosaurs were the only diverse big-bodied land vertebrates during the Jurassic and Cretaceous and, for as long as this was the case, other tetrapod groups were unable to achieve big body size. But in the same way that the modern world isn't really '…
tetrapodzoology | March 2, 2007
In the previous post we looked at the feathers and filament-like structures that covered the bodies of coelurosaurian theropods. While basal coelurosaurs - compsognathids and tyrannosauroids - possessed filament-like 'Stage 1' structures alone, members of Maniraptora (the coelurosaur clade that includes oviraptorosaurs, therizinosauroids, birds, deinonychosaurs and, probably, alvarezsaurids) possessed indisputable vaned feathers. That is, complex feathers that had a distinct central rachis with vanes on either side composed of parallel barbs. What is surprising is how luxuriant some of this…
tetrapodzoology | February 28, 2007
By now most people know that feathers are no longer unique to birds. Thanks mostly to a series of wonderful fossils from the Lower Cretaceous Yixian Formation of Liaoning Province, China, we now know that feathers first appeared in non-avian theropods, and were - later on - inherited by early birds...
What doesn't seem so widely recognised is that several researchers had been predicting the presence of feathers in non-avian theropods for an awfully long time, it's just that these people had been mostly dismissed as cranks indulging in way too much speculation. As it happens, the logic they…
tetrapodzoology | February 21, 2007
A story of cheeks, beaks, feathers, bizarre theropod dinosaurs, and truly, truly amazing fossils....
Yesterday I made a special visit to the University of Portsmouth's School of Earth and Environmental Sciences in order to attend a talk by, and meet, Professor Altangerel Perle, the famous Mongolian palaeontologist and finder of awesome Cretaceous dinosaur fossils. From the 1970s onwards, Perle has personally excavated and described such incredible fossils as the fighting Velociraptor and Protoceratops, the alvarezsaurid Mononykus, the unusual giant dromaeosaurid Achillobator, and the…
tetrapodzoology | January 29, 2007
It turns out that Cretaceous troodontid dinosaurs had asymmetrical ears. This makes them like owls, which also have asymmetrical ears. But not all owls have asymmetrical ears and, what's more, the story of ear asymmetry in owls is itself a pretty remarkable one....
Before getting distracted by godwits, I was talking about troodontids and their asymmetrical ears (and this itself came as a distraction, as beforehand I was talking about the evolution of blood-feeding in birds). The irresistible comparison that comes to mind is of course with owls, as owls also have asymmetrical ears (though…
tetrapodzoology | January 26, 2007
Apologies if you're here for the vampires. I'll come back to them soon, I promise, but in the meantime I got distracted...
Some biologists - and scientists from other fields - have been quite critical of the fact that people speculate, and speculate, and speculate about dinosaurs (and by 'people' I don't necessarily mean palaeontologists, as in fact most technical palaeontological literature is appropriately dry, boring and conservative). But let's be fair: how can anyone not try to imagine what these animals were like when they were alive? I will also say that informed (note: informed)…