Day 22: Therizinosaurus cheloniformis! The exclamation mark is wholly warranted, trust me. If ever there were proof that Evolution likes its whisky neat, it's Therizinosaurus. Around twice as tall as our waving, size-guide man, and a good nine metres long, pot-bellied, covered in feathers (or feather-like integument), and with a metre-long claw on each finger, Therizinosaurus looked a bit like something out of Pan's Labyrinth. It was a herbivore though (probably!), and presumably used the claws to slash up vegetation rather than other dinosaurs. It was a theropod, a group of bipedal dinosaurs that were overwhelmingly carnivorous, so it may have started out that way and evolved. Sort of like a panda then, both in terms of diet and general absurdity.

From Mongolia in the late Cretaceous (c. 70 million years ago), Therizinosaurus was something of a mystery for years, as people kept finding odd bits like claws and hands, and wondering what the bloody hell they'd unearthed. Palaeontology is always a bit like putting together a jigsaw without the picture on the front of the box, though as you learn more, and find more, it is possible to use comparative anatomy and educated guesswork to help out. And then sometimes you find a disassociated bit of Therizinosaurus in the desert, and are left boggling for half a century.

Therizinosaurus. What happens when Evolution has a night on the tiles.
Day 21: I'm not sure why, but lately all my dinosaurs seem to be starting with 'p'. Here's another. You've got to love Pachycephalosaurus wyomingensis. Imagine a mediaeval monk, complete with tonsure, then sprinkle his head with bony knobs, and you're... okay, not very close to Pachycephalosaurus, but it's a start. Not a big dinosaur - this one might make it to your shoulders, depending on how tall you are - but what it lacked in size, it seems to have made up for in attitude. Pachycephalosaurus is famous for its skull, and rightly so. Bristling with bumps, and with crowns as much as ten inches thick, it looks like they were made for fighting - specifically, for headbutting. Perhaps they fought each other the way that goats do today. Perhaps they deterred would-predators. Perhaps both. Either way, without some serious protection, a knock from a skull like that could do some damage.

An interesting thing about Pachycephalosaurus - if you need more interesting than a skull that would put a dragon to shame - is that, whilst long assumed to be herbivorous (its teeth were the flat, grinding molars familiar to herbivores) a recent skull discovery also bore very definite canines. So, was it an omnivore? Was Pachycephalosaurus charging about the late Cretaceous (North America, c. 67 million years ago), munching on smaller dinosaurs? Maybe it headbutted them to death. Possibly further discoveries will shed a little light. In the meantime, Pachycephalosaurus skulls. Admire, and mourn your own skully shortcomings.
Day 20: When I was a kid, I had a little plastic toy Polacanthus foxii. It was one of my favourites. The current models don't look much like mine did back then! One of the great things about science is how it moves forward, but it doesn't do to get too attached to a particular image of a dinosaur, because even ten years can see them completely reimagined, let alone thirty-plus years.

An ankylosaur, Polacanthus was originally found on the Isle of Wight (further specimens have since been found elsewhere in Europe). It dates from the early Cretaceous period, around 125 million years ago, and although not many specimens are known, we do know that it was armour-plated, as were all the ankylosaurs, and had some spikes as well for good measure. It would have been an herbivorous quadruped, probably about five metres long, slow-moving, and very well defended against predators. It probably wasn't invulnerable, but it can't have made for easy eating!
Day 19: Parasaurolophus walkeri was a hadrosaurid, a family of dinosaurs that tended to go in for head ornaments. In the case of Parasaurolophus, this meant a long, hollow crest that was connected to the nasal passages, and thus seems to have been capable of producing noise. This rather suggests that Parasaurolophus went about hooting a lot. The crests should have been capable of making different noises (alarm-raising, parental communication with young, mating displays, etc), and you can hear a recreation here.

The hadrosaurids were herbivorous, and seem to have travelled in herds. They've been called "the cattle of the Cretaceous" due to their ubiquity, and they seem to have been a major part of the diet of a lot of large, Cretaceous carnivores. Parasaurolophus (North America, c. 75 million years ago) would presumably have been no exception, although at ten metres long it would have been no pushover. It's easy to imagine them living in herds, co-operating to protect their young, and hooting at each other as they went about their business. Due to the vast number of hadrosaurids that existed, they're fairly well known in the fossil record (including skin impressions and even preserved soft tissue). This helps to make the family as a whole much better known to science than some of their fellow dinosaurs. Parasaurolophus fossils are scarcer than those of some other hadrosaurs, but general similarities in the family at large help to give a pretty good picture of how they lived.
Day 18: Psittacosaurus is adorable. Not sure it needs a lot more saying about it than that! The name means "parrot lizard", although it didn't look especially parroty, if we're honest. From the early Cretaceous (around 125 million years ago, in Asia), it was quite small, and decidedly beaky, although its "beak" contained teeth. One interesting thing about Psittacosaurus is how much variation there is within the genus. There are currently some ten species known, all exhibiting an assortment of adaptations, presumably to suit particular locations and situations. Lots of specimens have been recovered, some in such good condition that it's been possible to analyse them at the microscopic level, and see from the melanosomes roughly what colour Psittacosaurus would have been.

Adding to its cuteness (or oddness, depending on your point of view) is the big tuft of bristly projections on its nether quarters, which makes it look a bit like it had a punk hairstyle, but on the base of its tail. Presumably this was used for display, or possibly to scare off predators. Or both.

Picture here.
Day 17: From Mongolia in the late Cretaceous (around 73 million years ago), Protoceratops andrewsii was an early horned ceratopsid. Unlike its cousins, such as Triceratops and Styracasaurus, it was just a little thing, and far less horny. Specimens have had a tendency to be found en masse, which suggests that they were social creatures. They were also very cute. (Or at least, I think so!)

There's a very famous Protoceratops skeleton found apparently locked in mortal combat with a Velociraptor, which suggests that Velociraptor either preyed on Protoceratops, or - probably more likely - tried to attack their nests. This has led to Protoceratops gaining some notoriety in a world that generally prefers large predators over small herbivores.

Here's a picture of a Protoceratops watching over a hatching nest of its chicks, drawn by Rod Ruth.
Day 16: I love Compsognathus longipes. Long thought to be the smallest dinosaur, it's since been roundly beaten to that title, but nonetheless, it was a little creature that scurried around Europe in the late Jurassic, some 150 million years ago. It's actually been found with stomach contents intact, so we know that (possibly amongst other things) it ate small, fast-moving lizards. It would have been fast, then, and possibly feathered to some extent. (No specimens have been found with traces of feathers, but several of its relatives are known to have had coats of what have come to be known as "proto-feathers", like feathery forerunners.) Again, it would be nice to have a look, please and thank you.
Day 15: A dinosaur that needs more love. Kryptops palaios was found in the same rocks as Eocarcharia dinops (see day one), and consequently also came from Niger, c. 110 million years ago. A (probably) carnivorous theropod, it was roughly the height of a tall man. Very few fossils are known for Kryptops, with what there is making it possible to project the shape, and make a few educated guesses about diet and lifestyle. It's not especially glamorous, but there it was, nonetheless, strutting about West Africa in the early Cretaceous. Hopefully some more of it will be found some day.

The name means "old covered face", because the single specimen currently known appears to have had some sort of face covering, possibly of keratin. This might have served the same purpose as a vulture's bald head (easier to keep clean than feathers when you're sticking your head into entrails - although it's also been suggested that it might play a role in thermoregulation), or it may have been something to do with display. It's also been suggested that it might be some sort of mutation or chimera, and that Kryptops might actually be another Eocarcharia. Given the tremendous unlikelihood of a: being decently fossilised, and b: your fossil surviving 110 million years in order to be found, it's seems unlikely that a chance mutation would make it into the fossil record; but of course, it's by no means impossible.
Day 14: Knowledge and discovery are a complicated business. When I was a kid, to underline the fact that the flying reptiles (Pterodactylus antiquus, etc), and the marine reptiles (Plesiosaurus dolichodeirus, etc) are not dinosaurs, there used to be a mantra: Dinosaurs walk. They don't fly, and they don't swim. Then we found out that actually yes, they did (and do!) fly. And then we found out that they swam as well. Spinosaurus aegyptiacus is the most famous swimming dinosaur, although its British cousin Baryonyx has been known about for longer, but wasn't properly associated with a semi-aquatic lifestyle until later. Spinosaurus aegypticus (Egypt, c. 100 million years ago) was an absolutely massive creature with a sail on its back, and although a theropod (traditionally bipedal), it may have preferred a semi-quadrupedal gait on land, with its mass and balance better suited for the water. It doesn't seem to have been an obligate piscivore, however, so can't have been too ungainly on dry land. Basically it would be nice to go and have a look, please.

There's a handy size guide for big theropod predators here. Why the silly sod at the front is waving, I have no idea. Run, you bloody idiot!
Day 13: The species for which the carcharadonts were named, Carcharodontosaurus saharicus was found (as you might expect) in the Sahara, and dates from the mid-Cretaceous, around 95 million years ago. Although the first fossils of its kind were destroyed during WWII, more have since been found, and the close similarity of the teeth to those of the Carcharodon genus of sharks led to their name. Carcharadontosaurus had a huge skull over a metre and a half long, and was probably slightly larger than T. rex. Its skull wasn't as powerfully built though. As the saying goes, size isn't everything! Not that it couldn't have done a heck of a lot of damage, to pretty much anything it chose.
Day 12: Hesperonychus dates from about 75 million years ago, in Canada. It was a microraptor, a line of small, birdlike dinosaurs, but quite a bit younger than the others, which have so far been found in much older rocks. Hesperonychus seems to have been very plentiful, and was probably a small, scurrying sort of carnivore. Although some of the other microraptors appear to have been capable of flight, at least to a degree, Hesperonychus probably couldn't. It probably had wings of some kind though, used for balance when running, and perhaps for display.
Day 11: As you can probably guess from its name, Australovenator wintonensis came from Australia, and dates from the later Cretaceous (about 95 million years ago). A smallish hunter, it probably relied on speed more than strength, and as such, rather than having the huge head and massive jaws of some of the more famous carnivorous dinosaurs, Australovenator had what appear to be very agile hands, and more manoeuvrable arms than was normal for its kind. Like all the therapods, it was bipedal, and probably used its hands to hold onto its prey.
Day 10: Who doesn't love Styracosaurus albertensis? Less well known than its fellow ceratopsid Triceratops horridus, Styracosaurus was from the later Cretaceous (about 75 million years ago), in Canada, and looks like a heavy metal version of its more famous, and more recent, cousin. Seriously though, it's way cooler (image here). The frill is probably more for display than anything else, so it's debatable as to whether it could have done anything with those horn-like projections, but it's still fab.
Day 09: Tarbosaurus bataar (The Asian T. rex) was slightly smaller than its North American cousin (from current fossil evidence), but just as formidable. It was another of the later dinosaurs, living around 70 million years ago, and some argue that it should be called Tyrannosaurus bataar, given the similarity between it and T. rex. At the moment, Tarbosaurus is holding its own though, as there are enough differences between them to make it appear that both species evolved to suit different environments, and probably slightly different prey. Which I'm glad about, as Tarbosaurus means "alarming lizard", which amuses me, and I should be sorry to lose the name.
Day 08: Another good one for the study of evolution, Aardonyx celestae is a bit like a bipedal Diplodocus. Although it lived at the same time as a lot of the more familiar-looking sauropods, so didn't evolve into them, it seems to have been a bit of a throwback to an earlier type of dinosaur, and helps us understand how the earlier, bipedal animals gradually evolved into the tree-trunk-legged quadrupeds that everybody knows.

Here's a picture of it, by the great Julius Csotonyi.
Day 07: From Lake Nyasa in the mid-Triassic, some 245 million years ago, Nyasasaurus parringtoni is the oldest known true dinosaur. Like with the evolution from dinosaurs to birds, it can be hard to say when the first dinosaur was, and there's some argument that Spondylosoma may be the oldest. Or it may not be. In the meantime, Nyasasaurus is, unless you're one of those arguing that it's not a dinosaur either. Evolution is complicated. Especially when you only have a few bones.
Day 06: Now this one's fun. Years ago, a pair of massive fossilised arms were found in Mongolia, dating from the late Cretaceous (about 70 million years ago). Nothing else was found in the area, and for some fifty years, people argued about these massive arms, with their big claws. What did the rest of the dinosaur look like?! Without a head it's hard to tell whether you have a herbivore, omnivore or carnivore. Then, eventually, better specimens were found, and Deinocheirus mirificus took shape. An ornithomimosaur (bird mimic), it was a big, bulky, possibly at least partially feathered humpback, that seems to have eaten just about everything going. Wiki has a picture of the original arms here, with a woman for scale, and you can see a lovely (soundless, so safe for work) video simulation of it being a total dork here.
Day 05: A late dinosaur, from Romania some 70 million years ago, Balaur bondoc is an interesting one. It seems to have come from an island, and shows signs of island dwarfism. It had big, retractable claws on its feet (two on each foot, whereas most of its relatives only had one). Despite that, it appears to have been omnivorous rather than especially fighty, and some palaeontologists have suggested that it might even have been herbivorous, which was rare amongst the therapods. Trapped on an island, it may well have had to adapt to suit its surroundings, so omnivory seems like a good bet.
Day 04: From China in the early Cretaceous (approx 130 million years ago), Sinosauropteryx prima was an adorable little fellow with another funky name (Chinese dragon bird!) There have been some amazing fossils coming out of China in recent years, showing some really terrific detail, and they've been particularly great for preserved feathers. Sinosauropteryx was the first dinosaur to undergo microscopic analysis of its feathers, to examine the fossilised melanosomes (cells that give colour to feathers). Consequently, with an obvious nod to the fact that error is always possible, we now know that it was an orangey-brown, with white stripes. Knowing what colour dinosaurs were will never cease to be awesome.

Cute fossil here.
Day 03: Archaeopteryx, one of the most important dinosaurs in our unfolding understanding of the evolution of therapod dinosaurs into birds. Originally thought to be one of the earliest birds, it's since been reclassified as a dinosaur (and then a bird again, and then a dinosaur again). It's a dinosaur at the moment though, or was last I checked; and zoologically speaking they're the same thing anyway. The problem is, when one line evolves into another, there's no sharp line of delineation, but a series of small steps. So you have the non-avian dinosaurs on one side, the avian dinosaurs on the other, and a lot of murky sliding about betwixt and between. Which is where Archaeopteryx lies. Another German dinosaur this, and again from 150 million years ago, so quite possibly it flew over Sciurumimus, if not particularly gracefully.

Due to scanning elctron microscopy, and the good fortune of some very nice fossil specimens, it's been possible to look at the microscopic structure of Archaeopteryx's feathers, and it's generally assumed that they were black.
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