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Have a favorite dinosaur (or pterosaur, or other archosaur) that you would like to see me illustrate? Feel free to comment below! I can't promise that requests will be filled immediately, but I'd like to hear what you're interested in seeing, as I'm always looking for new ideas.
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I started this project mostly as a way to get myself back to doing some art after my graduate studies, and I'd say it definitely did the job - I feel more involved in art now than I have in a long time. Unfortunately now with a full-time job on top of the rest of my hobbies, I no longer have time to do one of these dinosaurs every day. But it was a fantastic summer project, and I'd love to thank those of you who followed it for looking and occasionally commenting.

I may periodically update this, especially as part of my new job involves doing some art for The Institute for Bird Populations, and birds are, as we all know, theropods! So do look forward to those, just not on a daily basis anymore.

So once again, thank you! You can always check out what I'm drawing these days at my twitter (@shichahn) or tumblr (tinylongwing) but right now it's a lot of fanart and occasional graphic design for a group of youtubers, so nothing really to do with dinosaurs. Still, I'd love to see some of you around every now and then!

Lauren



A perched Anchiornis huxleyi, done as a gift for my grandmother.
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As many of you know, I've recently relocated for work and have been apartment hunting the past few days while staying in a rented room. All of this has been fairly stressful and not left me much in the mood for drawing, but I know those of you who love my dinosaurs probably miss them. This one was done quickly, and more to get me back in the habit and mood for drawing than anything else. I do have a place to stay worked out now, but updates may still be scarce for a few days to a week while I get things squared away.

Anyway, this is Falcarius utahensis, an early Cretaceous Therizinosaur from - you guessed it - Utah, and the surrounding area. Nearly three thousand individuals of this species have been recovered, with many more still buried in massive bone beds - possibly the victims of a flood, or even several floods over a span of years that regularly deposited carcasses in the same general area. Unlike their fully-herbivorous descendants, Falcarius was omnivorous, and had other skeletal features like a short fourth toe and short hand claws that later developed in the Therizinosaurs into a longer fourth toe and very long plant-shearing claws.
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Heyuannia huangi was a late Cretaceous oviraptor from China, named for the village of Heyuan in which it was discovered. At around 10 feet long and roughly 45 pounds, it wasn't exceptionally big or small, and was probably fairly common. Although it is certainly an oviraptor, the structure of its shoulder girdles are very birdlike, and some researchers have even suggested that this may indicate that oviraptors are birds which evolved secondary flightlessness, like today's ratites - however, the general consensus among today's paleontologists is that oviraptors are pre-avian maniraptorans, much like the dromaeosaurs and troodontids.
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Hesperornis regalis was but one of many species in its genus, many of which lived in the Western Interior Seaway of Cretaceous North America. This toothed early bird was similar in many ways to today's grebes, loons, and penguins. It possessed short flipper-like wings that would have been somewhat useful for steering underwater, but certainly not for flight. Its legs were fixed at the ankle to the side of the body, and couldn't have been used for walking. On land, it would have had to push itself around with its toes and scoot on its belly, much like a seal - but underwater, those broad lobed feet were perfect for propelling itself swiftly after fish and other marine life.
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Dilophosaurus wetherilli was considerably different from how it was depicted in Jurassic Park. At roughly the height of an adult human and 23 feet long, it was quite a bit larger, plus it lacked the lizard-like frill the movie gave it - and nothing indicates that it would have spit venom, either, though to be fair, it's hard to completely rule out something like that. It seems unnecessary, though - in the Early Jurassic of western North America, it was already a large and formidable predator based simply on its heavy jaws and sharp teeth.

Similarly, no direct evidence of feathers exist in specimens of this dinosaur. One imprint of a sitting Dilophosaurus was once thought to show feathers through trace marks around the animal's feet and abdomen, but later analysis indicated the markings may have been left by plants the dinosaur sat on, or perhaps were the result of erosion. Nevertheless, the chances are very good that Dilophosaurus was feathered, given how many of its relatives were.
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Geosternbergia sternbergi was one of the Cretaceous period's giant pterosaurs, with a wingspan of up to nearly 20 feet. The lower jaw alone on a large male could be as much as 4 feet long. Many fossils of this species have been found of both sexes and various ages. Compared to adult males, both females and young males were smaller and bore shorter, somewhat triangular crests, but females can be separated from males of any age by their wider, more robust hips - the better for laying eggs with. These pterosaurs were probably mostly coastal, and have been found along the shore from Alberta to New Mexico along what was once the Western Interior Seaway, now the western Great Plains.
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Therizinosaurus cheloniformis is a giant herbivorous theropod from Cretaceous Mongolia. Originally thought to be a turtle when it was discovered in 1954, further fossil discoveries confirmed its identity as a dinosaur. The actual skull of Therizinosaurus has never been found, but a herbivorous diet is most likely as every other known species in the therizinosaur family is herbivorous.

Like Nothronychus, which I illustrated early on, Therizinosaurus bore massive Edward Scissorhands-like claws, which it most likely used to grasp and shear plants to eat. It was also heavily feathered, and as it was far too big to fly, at 33 feet in length and five tons in weight, those feathers were most likely for display purposes.
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Spinosaurus aegyptacus, as its name implies, was first discovered in Egypt and lived in North Africa during the mid-Cretaceous. This sail-backed predator is the largest-known theropod, at 40-60 feet in length, though estimates of its weight vary wildly from 7-23 tons. To give a better idea of scale, the sail on its back is roughly 5 and a half feet tall.

A member of the Megalosauria, Spinosaurus had a highly-modified skull convergent with modern crocodylians, suggesting it may primarily have eaten fish, although with its large size and strong jaws it may certainly have been more opportunistic than that and probably could have eaten anything it could catch. The sail on its back, meanwhile, may have been similar in purpose to the plates on the back of the Stegosaurus from the other day - it may have been used in thermoregulation, or in sexual display - or, as some have suggested, the spines may not have supported a sail but instead a camel-like hump, where fat was stored. We do know for certain that Spinosaurus was at least semiaquatic, though, based on isotope analyses of fossilized teeth, and a hump may have impeded swimming while a sail likely would not have.
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Drawing time today was replaced by museum time as I went to visit OMSI's summer exhibit, "Dinosaurs Unearthed", which is a traveling exhibition hosted by these folks. I'd been meaning to get there all summer long and finally today I made it over. The show bills itself as using "the latest in fossil evidence to take a captivating look at the dinosaurs’ fascinating — and feathered — history." How could I resist?

Photos and review within! )
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Stegosaurus stenops is probably the best-known dinosaur to the general public that I've posted here, but despite being discovered in 1887, and being represented by multiple fairly intact skeletons, it has puzzled paleontologists in many ways, and continues to do so. Various Stegosaur species were widespread throughout North America and Europe in the Late Jurassic, but S. stenops specifically was from the region represented today by Colorado, Utah, and Wyoming. Since its discovery, the orientation of the back plates, tail spikes, and the animal's entire posture, have been redesigned and reorganized until arriving at what is currently considered an accurate restoration - alternating back plates, rather than in pairs; tail spikes held outward at an angle rather than upright; and an active posture, with head and tail held high.

The purpose of the plates, meanwhile, are what gives this image its title. Too fragile to be armor as originally assumed, the plates are filled with a network of blood vessels. They may have been used for thermoregulation, much like rabbits' ears - by carrying blood out away from the body through an organ with large surface area, they help cool the blood down and lower the body temperature. However, the most recent accepted hypothesis is that Stegosaurus could have used the plates for communication. By flushing high volumes of blood into the capillary network in the plates, they could change their color from a neutral tone to a bright red to intimidate enemies or rivals, or attract females. Birds today such as the Crested Caracaras do this, and are able to change the colors of their faces from gray to yellow to red in order to communicate their emotional state.
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Archaeorhynchus spathula is the earliest-known beaked bird. Found in the Early Cretaceous period in the Yixian Formation of China, these birds were capable of powered flight and were primarily herbivorous, probably filling a niche similar to today's pigeons. It is currently also the most basal member of the Euornithes known - Euornithes being the branch of birds encompassing all known modern species.
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Leaellynasaura amicagraphica (a hefty name for a very small dinosaur!) was an Early Cretaceous ornithopod from Australia. At the time, Australia was much nearer to Antarctica than it is today, and dinosaurs that lived there had to be able to handle cold, dark winters much like the arctic species I've already illustrated. How an herbivore would survive these winters is still unknown, as plant life would have been extremely limited during the months of darkness. Perhaps they were able to hibernate, like today's polar mammals, or perhaps they were able to survive by eating roots and bark. While we do not have direct evidence that Leaellynasaura was feathered, it almost certainly would have been - relatives such as Tianyulong and especially Kulindadromeus from a couple days ago demonstrate that ornithiscians were feathered, and the insulation that feathers provide would have been crucial for the survival of such a small animal during the winter.
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Pelecanimimus polydon was a primitive ornithomimosaur from the Early Cretaceous period in Spain. Named for its throat pouch, a cast of which was preserved in the original fossil, this species had long, narrow jaws and small teeth, long legs, and other adaptations in addition to the pouch that suggest it was similar to today's herons - a wader, and a piscivore. The crest on its head is also soft tissue or possibly keratin, rather than bone.
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I return from an extended break with a quick drawing of Kulindadromeus zabaikalicus. Discovered in 2010 in Russia, this species was finally published just a few days ago, and what it reveals is something many paleontologists have long suspected but, until recently, were unable to provide concrete evidence for. Kulindadromeus is a primitive neornithiscian herbivore from the Jurassic period which sports a coat of shaggy protofeathers, or "dinofuzz" as it has been nicknamed, similar to that of later theropods. These feathers cover the animal's entire body except for its hands, feet, and tail. A small handful of other ornithiscians had quills, as we have seen, or other feather-like filaments, but the latest find clearly demonstrates that since early ornithiscians had what are most definitely feathers of similar structure to the feathers some theropods had, feathers evolved early on in the dinosaur family tree and appear to have evolved once, not multiple times. Most likely, many dinosaurs, if not all, had feathers at some stage in their lives. What's more, this find lends credence to the hypothesis that feathers originally evolved even earlier in archosaurs, and that the fuzz on pterosaurs comes from the same evolutionary line.
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Pachyrhinosaurus canadensis is one of several Pachyrhinosaur species that lived in the high arctic of Canada and Alaska during the Late Cretaceous. While it was slightly less frigid at the time than it is now, winters were still dark and snowy. No fossilized Pachyrhinosaurs have preserved quills, but we do know that their ancestors were quilled, and it isn't beyond reasonable speculation to suspect that it may have had quills, possibly modified into something like a furry coat, in order to help it maintain body temperature during the winter. We also still don't know what these or other arctic herbivores ate during the winter - they may have migrated, some of them, but some fossils of this species were buried during spring snowmelt floods, suggesting that if they did migrate out of the snowy areas, they would have come back fairly early in the season.
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Changyuraptor yangi, unearthed in 2012 and officially published three days ago, is the largest-known Microraptorine dinosaur found to date. At four feet long and with an estimated weight of nine pounds, this eagle-sized theropod also possessed hollow bones, four wings, and very long tail feathers, and gives every indication of being capable of gliding flight. Those long tail feathers are the longest known for any dinosaur species, and likely would have been used to steer and also to break the creature's fall as it came to a landing, as its large size would have required more braking power than smaller flighted dinosaurs.

The two in my illustration are juvenile siblings - fully-grown, but still mentally immature. Many modern birds of prey at this age play-fight, as these two are seen doing, as they hone their balance, flying, and other skills that will later help them capture their own food.
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Mei long, or "sleeping dragon", is a small (duck-sized) troodontid from the Early Cretaceous period in China. Both fossils found so far were found in a sleeping posture, with the snout tucked under one wing, and the tail curled around the body, in a pose similar to how birds today sleep. Both Mei that have been found appear to be juveniles, but it is likely that even as adults they wouldn't have gotten much larger.
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Neither a dinosaur nor a pterosaur today! Sharovipteryx mirabilis was an early gliding reptile from Kyrgizstan's Late Triassic period. Only one known fossil of it exists, and where exactly it lies on the reptile evolutionary tree is still unknown, though it does appear to be related to the very early archosaurs, the line which also gave rise to dinosaurs and pterosaurs. It is not an ancestor of theirs, of course - dinosaurs were already around in the Triassic, after all. Instead, think of it similarly to how lemurs are related to us - they're close relatives of more basal primates, but we did not arise from them.

The original discoverers of this fossil, back in 1971, concluded that the wing membrane did not connect to the hands. However, more recent analyses indicate that if Sharovipteryx did have wing membranes attached to the hands, it could have used that forward gliding surface to more accurately control its flight. Unfortunately the portion of the rock that had contained this membrane was carved away when preparing the fossil, so unless another is found, we may never know for sure how far the membrane actually extended.
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