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.

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.

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.

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.

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.

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.

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.

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.

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.

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.