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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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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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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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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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Daemonosaurus chauliodus was a Late Triassic theropod from New Mexico's Ghost Ranch site. During the Triassic, it was a dense forest, and now a thick layer of coal lines the rocks where Daemonosaurus and its contemporaries were found. Most Triassic theropods have long, narrow snouts, so Daemonosaurus, with its short rounded snout and buck teeth, was a very unique find when it was discovered in 2011. Unlike Coelophysis, fossils of which have been found in the hundreds in this area, we only have one Daemonosaurus skeleton on record so far, but it seems to have died similarly, trapped in a flash flood during one of the region's severe monsoons.
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My grandmother's 93rd birthday is coming up next week and I told her I would do some art as a gift. Little old ladies, my grandmother included, typically prefer extant dinosaurs to extinct ones, and she's a fan of hummingbirds, which she has lately been trying to attract to her yard. Rufous Hummingbirds (Selasphorus rufus) are a common sight here in the Pacific Northwest, and while they're drawn to a wide range of flowers, western red columbines (Aquilegia formosa) are one of their favorites.

And I think this bit of art stands as an interesting contrast to the rest of the dinosaurs, too - just look at how highly modified they've become over the last several million years! From one line of small theropods came an extremely wide diversity of modern birds with an astounding variety of shapes, sizes, and special adaptations for filling almost every niche on the planet.
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Sanjuansaurus gordilloi is a very primitive dinosaur from the late Triassic period in Argentina. During the Triassic, large agile crocodiles were the dominant terrestrial predators. Early dinosaurs, still very lizard-like with their small hands, four-toed feet, and general lack of diversification into the fantastic body shapes later eras saw, were prey more often than predators. They were small and unimpressive, and scampered about searching for insects and other small reptiles to eat.

Sanjuansaurus' habitat was, at the time, volcanically active. While much of it was covered by forests, fresh lava flows occurred regularly. Small, mobile predators like Sanjuansaurus might have been able to take advantage of these dramatically-altered ecosystems and hunt between the rocks for early colonizers such as spiders and lizards.
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Yandangornis longicaudus is, as the name ("ornis") implies, a bird. We think. It's actually very hard to say. Like birds, it is fully-feathered and has a beak with no teeth. However, it also has a long bony tail, a short fourth toe, and other skeletal features that make it more similar to dinosaurs. Since birds are dinosaurs, the distinction is purely one of interest to taxonomists, who work to figure out which species are more closely related to which other species. From a taxonomic perspective, Yandangornis is a dinosaur, as are all birds - but whether or not it can be called a bird for sure is still up for debate. Discovered in Zhejiang Province, China in 1999 from a largely intact skeleton, we do know that it was more adapted for ground-dwelling than aerial or arboreal life, and was similar in size and habit to today's roadrunners, likely chasing down insects, small reptiles, and primitive mammals on foot.

As a heads up, updates will be spotty over the next couple weeks as I finish my thesis and prepare my defense. I'll try not to go full hiatus on you guys!
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Sinornithomimus dongi was found in the highlands of Mongolia in 2003. Late Cretaceous Mongolia wasn't all that unlike the Mongolia of today, and these ostrich-like theropods, which lived in small herds of similarly-aged individuals, would have had to pass through expansive desert areas to reach pockets of water once snowmelt became scarce in the summer. Many of the individuals we have fossils of include some of the most complete dinosaur skeletons, found having evidently been trapped in the mud at a water hole.
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Ceratosaurus nasicornis is a late Cretaceous theropod from western North America. Discovered in 1884, its original describer felt that the unusually large (for a theropod, anyway) horns on its face were deadly weapons, in line with the general sentiment at the time that dinosaurs were absurdly brutish and violent compared to modern animals. Today, paleontologists feel that the horns might have been used in male-male combat over territory or females, or that possibly the horns were purely for display purposes. Males and females may have had differently-colored or differently-sized horns, or they may have been useful in species recognition, as Ceratosaurus was not the only large theropod in its habitat.
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Balaur bondoc was an apex predator on Hateg Island, the late Cretaceous portion of Romania from which we know so much about the effects of island life on dinosaur evolution. Balaur was roughly the size of a turkey, with unusual proportions for a dromaeosaur - short, robust arms and legs, only two fingers on its hand, and with not just one but two sickle claws on each foot due to a highly modified inner toe. It wasn't a graceful sprinter like its relatives, but it was powerful and likely capable of taking down prey larger than itself. This one has caught a juvenile Zalmoxes robustus, an iguanodontid, still young enough to have a coat of down. Like Magyarosaurus and other Hateg dinosaurs, Zalmoxes grew much smaller than its relatives, an example of island dwarfism. As an adult, it would not have exceeded 7-10 feet in length, considerably smaller than the nearby Iguanodon species of continental Europe which reached 30-40 feet long as adults.

And with this I am officially back from my hiatus! It was longer than I'd anticipated it being, but that's thesis work for you sometimes.
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Buitreraptor gonzalezorum is a unenlagiine dromaeosaur from Cretaceous Argentina. Unlike more typical dromaeosaurs, it had very long, thin legs, as well as a long slender snout filled with small, strongly recurved and grooved teeth. Rather than hunting larger animals or living in packs, it appears likely that Buitreraptor captured smaller animals - mammals, lizards, and amphibians, for example. Others, however, including Scott Hartman, a well-known skeletal restoration artist, have speculated that Buitreraptor's proportions and tooth shape suggest it may primarily have been piscivorous, making it the prehistoric equivalent of a heron or egret.
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Concavenator corcovatus is a carcharodontosaur, one of several medium-to-large carnivores from Cretaceous Southern Europe. Discovered in Spain in 2010, it is the only known carnosaur with a sail on its back. This sail is unlike those of the early synapsid Dimetrodon, or the spinosaurs, in that rather than being tall and thin, it was low and likely wide at the base - possibly for display, possibly for fat storage such as in today's camels, or potentially for both purposes.

Concavenator also has large bumps on its forearm bones that appear to be quill knobs, and skin impressions show that its body was covered in large alligator-like scales.
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Archaeopteryx lithographica has, until recently, enjoyed its place in the spotlight as the link between dinosaurs and birds. When it was discovered in 1861, it was regarded as a bird, but one with unusually dinosaur-like characteristics, including a long bony tail, clawed hands on the wings, and a toothed snout. As more specimens have been recovered, however, and with more and more feathered theropods being found every year, it has become evident that Archaeopteryx may not be the all-important transitional stage we once thought it to be. While some paleontologists maintain that it belongs in Avialae, others have suggested it may in fact be a troodontid or other maniraptoran, and therefore still a close relative of birds, but no more so than a species like Velociraptor, rather than a likely ancestor of modern birds. Whatever the case may be, it was certainly an important discovery in its time, and remains a well-known public ambassador for the evolutionary history of birds.
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