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Hi everybody. Here is my latest Hell Creek paleo-art. Say hello to Dakotaraptor steini, a large dromaeosaurid raptor that lived in South Dakota at the end of the Cretaceous Period. How large? We don’t have an exact measurement because this animal is known only from partial remains. However, enough was recovered to give a ballpark estimate that the creature measured somewhere around 15 to 20 feet long. Not as big as Utahraptor, but still pretty impressive.
Dakotaraptor steini. © Jason R. Abdale. May 26, 2018.
This drawing was made with No. 2 pencil, Crayola and Prismacolor colored pencils, a black felt-tipped marker, and A LOT of touch up work on the computer in order to make the scanned image as bold and vivid as it is in real life.
In either the late 1930s or in the year 1940, the front half of a fossilized skull was discovered in Huangchiatien (also called Dahungtien), Yunnan Province, China. It was named and described as Lukousaurus yini by Chung Chien Young in the year 1940 (Young, Chung Chien. “Preliminary notes on the Lufeng vertebrate fossils”. Bulletin of the Geological Society of China, 20 (3-4) (1940). Pages 235-239), and it was described further in 1948 (Young, Chung Chien. “Further notes on Gyposaurus sinensis Young. Bulletin of the Geological Society of China, 28 (1-2) (1948). Pages 91-103). The holotype specimen is housed within the Institute of Vertebrate Paleontology and Paleoanthropology, which is located in Beijing, China, and it has been given the identification code of “IVPP AS V.23”.
Below is a drawing of the partial skull made by Tracy Ford.
Partial skull of Lukousaurus yini. Illustration by Tracy Ford. From The Dinosaur Society Dinosaur Encyclopedia, written by Don Lessem and Donald F. Glut. New York: Random House, Inc., 1993. Page 279. Image used with permission.
Lukousaurus lived during the early Jurassic Period, approximately 195 million years ago (MYA). Based upon the size of its remains, which consist only of the front half of its skull, it may have been six to eight feet long.
Some may cite Lukousaurus for its old age, but what grabbed my attention was when I read that the teeth had serrations only on the back edge. I had been told that this is a feature that is only found in the carnivorous dinosaurs commonly called “raptors”, more properly known as Deinonychosauria. This clade is divided into two families: Dromaeosauridae and Troodontidae. According to this source, all dromaeosaurids had teeth which were serrated only along the posterior (back) edge, and some troodontids had this feature as well. Although all raptor dinosaurs are found during the Cretaceous Period, paleontologists have hypothesized for years, based upon phylogenic analysis, that the ancestor of the raptors appeared millions of years earlier during the Jurassic Period. It may well be that Lukousaurus is that ancestor. Could it be that Lukousaurus is the oldest-known “raptor”?
Unfortunately, the information which I had read concerning raptor tooth serrations was later shown to be incorrect. I proposed this idea of Lukousaurus being a basal raptor on an online paleontology forum. In response, I was contacted by Jim Kirkland, a well-known paleontologist from Utah, who corrected me by saying that Deinonychosaurians actually DO have serrations on both the front and back edges of their teeth, but their anterior (front) serrations are much smaller than the posterior (back) serrations. In fact, in many specimens, the front serrations are so small that they are practically non-existent – you need a microscope to see them. This shows the danger of basing a hypothesis upon incorrect information, because this taints your reasoning and your conclusions.
I myself have not seen the actual specimen of Lukousaurus, nor do I know anyone who has. The claim is that Lukousaursus had absolutely no serrations on the front edge of their teeth. However, it was also claimed in another source that raptor dinosaurs didn’t have any serrations on the front edges of their teeth either – a statement that was proven false. Is it true that Lukousaurus had no anterior tooth serrations, or are the serrations so tiny that they cannot be seen with the naked eye?
If it is true that Lukousaurus had absolutely no serrations on the front edges of its teeth and only had serrations on the back edges of its teeth, then this invalidates the hypothesis that it might be a basal Deinonychosaurian, and it must belong to some other dinosaur group, if indeed it is a dinosaur at all; it has been proposed by at least one person that it might, in fact, be a crocodilian. However, what if Lukousaurus possessed teeth that are similar to raptors, with prominent serrations on the posterior edge, and miniscule serrations on the anterior edge, serrations that are so small that they were not noticed? If this is the case, then it is possible that Lukousaurus might, in fact, be a very primitive raptor dinosaur.
Evidence to back up this claim is very thin. But let’s assume for the time being that it is a dinosaur. Is there any evidence which suggests that Lukousaurus might be a member of Deinonychosauria, or perhaps a close relative?
The first piece of evidence to support the hypothesis that Lukousaurus is a very primitive raptor is its age. Paleontologists have speculated that raptors appeared during the Jurassic Period, specifically either the early or middle Jurassic. The reason why is because birds are believed to have been descended from raptors, and the oldest-known birds come from the late Jurassic – therefore, raptors must have appeared earlier. Lukousaurus comes from the early Jurassic.
The second bit of evidence is geographic location. Raptors are believed to have originated in Asia and then spread elsewhere. Lukousaurus comes from China, specifically the Lower Lufeng Formation in Yunnan Province, China. It would have shared the landscape with the prosauropods Gyposaurus, Lufengosaurus, and Yunnanosaurus. It would have also lived alongside the early carnosaur Sinosaurus and the ornithischian Tatisaurus (we’re not sure if it was an ornithopod or an early thyreophoran; it might have looked similar to Scutellosaurus).
The third piece of evidence, which I have already mentioned before, is tooth structure. Lukousaurus’ teeth are very thin and blade-like, and are sharply recurved backwards. What is especially noteworthy is that it is claimed that the teeth have serrations only on the posterior edge. This feature was stated to also be present in raptors, but as I said earlier, this was dis-proven.
This brings about the fourth piece of evidence, although this is subject to intense debate – taxonomy. It has been hypothesized that Lukousaurus was a coelurosaur, and the coelurosaurs were the ancestors of Maniraptora. This clade includes the ornithomimids, the therizinosaurs, the oviraptorosaurs, and the raptors. However, due to the incredibly fragmentary nature of Lukousaurus – it is, after all, known only from one fragmentary snout – its phylogenic position is uncertain. Yes, it has been classified as a coelurosaur, but it has also been classified as a ceratosaur, and even as a crocodilian. So, using taxonomy as evidence is incorrect; it’s more likely an opinion rather than evidence.
Lukousaurus might be an early raptor, but personally, I think it is an advanced coelurosaur which shows the beginning of raptor-like traits. This would make Lukousaurus a borderline coelurosaur-maniraptoran. Until more material from this particular species is uncovered, any assertions made as to which clade this creature belongs to will always be tinged with uncertainty.
- Lessem, Don; Glut, Donald F. The Dinosaur Society Dinosaur Encyclopedia. New York: Random House, Inc., 1993.
- Padian, Kevin, ed. The Beginning of the Age of Dinosaurs: Faunal Change Across the Triassic-Jurassic Boundary. Cambridge: Cambridge University Press, 1988.
- The Theropod Database. “Lukousaurus in Nesbitt’s matrix”, by Mickey Mortimer (May 7, 2011). http://theropoddatabase.blogspot.com/2011/05/lukousaurus-in-nesbitts-matrix.html. Accessed on December 24, 2013.
- Dinosaur Mailing List. “What is Lukousaurus?”, by Mickey Mortimer (September 4, 2000). http://dml.cmnh.org/2000Sep/msg00086.html. Accessed on December 24, 2013.
- The Bite Stuff. “Troodontid Teeth – WP#6”, by Jaime A. Headden (June 6, 2010). http://qilong.wordpress.com/2010/06/06/weekly-picture-6-troodontid-teeth/. Accessed on December 24, 2013.
- The Paleobiology Database. “Lukousaurus yini”. http://paleobiodb.org/classic/checkTaxonInfo?a=checkTaxonInfo&taxon_no=64286&is_real_user=0. Accessed on April 19, 2020.
- The Paleobiology Database. “Huangchiatien, Lufeng (Jurassic of China)“. http://paleobiodb.org/classic/basicCollectionSearch?collection_no=49773&is_real_user=0. Accessed on April 19, 2020.
Hello all. I’ve recently finished an important writing project that I’ve been laboring upon for months. Now that it’s finished, I have a little breathing room to do art, and this is what I’ve done so far. I decided to do an updated version of an old illustration that I had made of an Ornithomimus. While the general color scheme was what I had in mind, I was never truly happy with the end-product. This latest version is much more in line with what I was imagining the “Bird Mimic” would look like.
Here is the “before” picture, made in 2013.
And here is the “after”, made today.
You’ll notice several differences right away, the most noteable of them being the re-shaping of its wing feathers. While Ornithomimus, or perhaps ornithomimids in general, had pennaceous feathers, I don’t think that they had primaries, because those would have been attached onto the wrist and the hand. This would have been difficult for ornithomimids because, unlike “raptor” dinosaurs (dromaeosaurids and troodontids), ornithomimids could not flex their hands backwards. I also increased the size of its tail feathers, made the neck thicker, changed the shape of the skull so that it was more anatomically accurate, and added Secretary Bird-style feathers to the back of its head. So much for form. In terms of color, I made it more vibrant, with deeper richer yellows and oranges and a lot more black patches. I changed the color of its bare skin from pink to a mixture of tan and black. I made its beak black, I changed its eye from yellow to blood red, and gave it black feet.
I can definitely see this character rushing about on the plains of the Hell Creek Formation. This shows that artists should never be stagnant. They must always strive to improve their work, and in so doing, improve their skill.
This drawing was made on computer printer paper with a No. 2 pencil, Prismacolor colored pencils, markers, and a black felt-tiped pen. The size of the drawing, from the tip of its nose to the tip of its tail feathers, measures 10.75 inches long, which is almost 1/12 scale, as the real animal possibly measured 12 feet long with its neck and tail fully stretched out.
Keep your pencils sharp.
The image of Nature “red in tooth and claw” is a compelling vision which appeals to the popular imagination. Time and again, paleo-art illustrations depict dinosaurs and other prehistoric animals actively engaged in fighting, hunting, and killing. It’s a well-known fact that violence sells, and it’s also a well-known fact that the animal kingdom can sometimes be very brutal. But was the Mesozoic world really a landscape of perpetual violence and bloodshed with animals constantly engaged in the savage business of survival?
Most naturalists, biologists, and animal behaviorists today would say “probably not”. Animals do not engage in a perpetual brawl-fest with each other. Even so, animals do have violent interactions, not only among different species (inter-species combat), but also within the same species (intra-species combat). The dinosaurs were no exception to this, and we have many pieces of evidence that individuals within certain dinosaur species engaged in violent behavior towards each other.
Before I get into the particulars of the paleontological evidence, it’s important to establish some ground rules as to the sort of intra-species combat that animals engage in today, and what the dinosaurs likely engaged in during the past. Physical combat between individuals or at least physical harm inflicted by one individual upon another is typically rooted in either social or environmental causes. Animals hurt each other for a variety of reasons, but seldom is it done purely for the hell of it – only people do that. Social reasons for intra-species combat include violence associated with mating and with mate selection. Bighorn sheep rival males cranially collide with each other until one contestant or another gives up. Other individuals within numerous animal species fight each other in order to assert their right to mate. Mating-based violence can also include some very rough love – some males within certain shark species will actually bite the females in order to assert their power over the female. Speaking of this, asserting dominance is also one of the main causes for intra-species violence, regardless of whether or not mating is involved. This involves dominance within a hierarchy system, such as a lion pride or a wolf pack. Other reasons for intra-species combat are environmental, and are usually tied to the availability of food and other resources. Territorial defense in a strong motivator in this behavior, and this is strongly tied to yet another reason, which is competition of food.
Now that we have established some of the motivating factors behind why modern animals hurt each other, let’s examine the sort of intra-species combat that dinosaurs would have engaged in. For instance, many animals will kick either out of aggression, self-defense, or purely to express annoyance. One dinosaur that possibly engaged in combative kicking was the late Cretaceous ornithopod Parksosaurus. This small speedy herbivore possessed unusually long scythe-like claws on its feet. One may hypothesize that Parksosaurus engaged in kicking contests like in cockfights, or like the modern-day Australian cassowary bird. Then again, Parksosaurus could have also used these long claws for better traction when running, like the cleats on a runner’s shoes, or could have used them like digging tools to scratch into the dirt to search for food or water.
Of course, when people imagine kicking dinosaurs, the first thing that likely pops into their minds are the “raptor” dinosaurs, such as Deinonychus, Velociraptor, and Troodon. Did raptor dinosaurs, with their killing claws, do the same? The large hook-shaped toe claws were certainly used for a specific function, either ripping prey open or pinning it to the ground. I can easily imagine two bird-like raptors squabbling with each other and kicking out with their feet, like a pair of roosters, but this is purely speculative as there is no hard evidence for raptors engaging in kicking each other.
Acheroraptor. © Jason R. Abdale. July 16, 2014.
Years ago, it was proposed that another meat-eater, the late Jurassic carnivore Ceratosaurus, could momentarily balance itself on its thick tail like a kangaroo and kick out. However, this idea has since been disproven. In order for this kicking behavior to work, the tail has to be very thick and muscular and at the same time be very flexible. Ceratosaurus’ tail was deep, but thin in cross-section, more like a crocodile’s tail than a kangaroo’s. Furthermore, it only had limited up-down flexibility. For the most part, the tail was held stiff for balance, and its range of flexibility was largely confined to side-to-side motion, not up-and-down.
Ceratosaurus. © Jason R. Abdale. April 23, 2012.
Ceratosaurus is famous for having a prominent horn on the end of its nose, hence its name. However, the horn was very thin and blade-like in form, and was certainly used for display rather than offensive action. However, there were dinosaurs and other animals in the past that likely used their heads as weapons. “Head-butting”, when animals engage in combat by using their heads as hammers, possibly occurred in earlier animals, such as the dinocephalians of the Permian Period. They had thick flattened skulls, and either pressed and shoved against one another or might have collided cranium against cranium. The dinosaurs which are most associated with head-butting are the marginocephalians, “the wide skulls”, the group that includes pachycephalosaurs and ceratopsians. At first glance, their skulls seem to have been specially designed for head-on physical combat. The eponymous Pachycephalosaurus had a rounded skull that was a solid foot thick, and many scientists have automatically assumed that such skulls were used in head-butting contests, like with modern-day bighorn sheep. A recent study by the University of Wisconsin has found that 20% of pachycephalosaur skulls exhibit head trauma, suggesting with some certainty that the pachycephalosaurs did indeed engage in head-butting behavior.
Pachycephalosaurus. © Jason R. Abdale. October 19, 2013.
But what about the other members of the marginocephalians? The ceratopsians, “the horned faces”, which include the likes of Triceratops and Styracosaurus, have also been assumed to have been highly combative animals, with their spikes, horns, and frills. In recent years, the idea of these horned behemoths duking it out with each other or impaling predators on their sharpened horns has come under intense criticism. Many of their frills are dominated by wide holes which served to lighten the weight but also made them practically useless for protection. Some scientists think that the frills and horns were primarily there for display and species recognition, and their use in defense was only an afterthought.
Chasmosaurus. © Jason R. Abdale. March 31, 2016.
As you’ve probably seen by now, most of the animals which have physical features that can be used in combat are herbivores. Why? Because they sometimes have to physically fight in order to stay alive and avoid being eaten by carnivores. Aside from teeth and claws, the meat-eating theropod dinosaurs don’t seem to have much in the way of special features that would be involved in fighting, not just eating. Ceratosaurus’ nasal horn was too thin and flimsy for attacking something, and so too were the eyebrow horns of its larger contemporary Allosaurus. However, another carnivore did possess eyebrow horns which very well might have been used in fighting – Carnotaurus, one of my personal favorites. Ever since its discovery in the 1970s, paleontologists and paleo-artists have imagined this dinosaurian toro engaged in head-butting clashes with other members of its kind. However, based upon the build of the skull, it seems more likely that it was engaged in cranial “shoving matches”, in which both competitors would press their skulls against one another (hence the Velcro-like arrangement of bumps and nodules on the top of their heads in between the horns) and proceed to push and shove in a demonstration of pure muscular strength until one side or another decided that their opponent was too strong, and retreated.
While predators might not necessarily have physically struck each other with their skulls, they could have used their heads in another way that is far more common among carnivorous animals of all sorts today – face-biting. Face-biting is a way to assert dominance among individuals, especially in communal or pack-hunting societies. Several modern carnivorous animals, such as lions, foxes, and wolves, engage in this behavior. The infamous creature known as “Jane”, who might be either a Nanotyrannus or a juvenile Tyrannosaurus (to this day, nobody is exactly sure), has evidence of face-biting. Since many animals today who engage in face biting do so in order to assert their position of dominance in a pack society, this could be further evidence that this animal was itself a pack hunter, at least as a juvenile. At least one specimen of a juvenile Daspletosaurus also has evidence of face-biting. Sue the T. rex possesses marks on the jaw which were previously thought to have been the result of bites, but were later proven to have actually been caused by a bone infection.
Predators aren’t the only animals today that engage in face-biting, so there may have been herbivorous dinosaurs that engaged in the same behavior. The most likely candidate for this is the small African herbivore Heterodontosaurus. The tusks on this creature could have been wielded in actual biting, or they could have been used for fang-bearing contests like modern baboons. Many animals bear their fangs or canines when aggressive, and Heterodontosaurus possibly did this to intimidate rivals and scare off predators. Another animal that can be compared with Heterodontosaurus is the musk deer. However, their long saber-like canine teeth are grown for display, not combat. Musk deer grow huge teeth instead of growing antlers in order to over-awe rival males and to impress females.
Another possibility for serious dinosaur fights was among the sauropods. With their massive builds, any hit, no matter how light, likely would have caused some kind of damage. One modern long-necked animal that uses its body in sheer brute force is the giraffe – a rather placid-looking animal, but don’t make it angry. During the mating season, male giraffes will proceed to whack each other, swinging their long stiffened necks around like baseball bats, with the short stumpy horns on the tops of their heads inflicting some serious pounds-per-square-inch. Some sauropods, like Apatosaurus, had very massive thick necks in proportion with their body size. This leads some to speculate that Apatosaurus and its ilk used their bruiser builds to inflict bruises on others.
Apatosaurus louisae. © Jason R. Abdale. May 11, 2020.
But what about the opposite end of a sauropod? For many of them, the tail was just as long, or longer, than the neck. Tails can be effective weapons. Crocodilians and monitor lizards engage in tail whacking as a way to ward off threats. Many sauropods had thick tails, but others, like Diplodocus, have very long thin tails, and some believe that these long whip-like tails were indeed used like whips. A sharp crack across the side would make any Allosaurus wary.
Diplodocus carnegii. © Jason R. Abdale. May 11, 2020.
Of course, there are dinosaurs that almost certainly used their tails specifically for combat: the stegosaurs and the ankylosaurs. Evidence has been found for injuries inflicted by these animals upon predators, but I’m not certain if any evidence exists for stegosaur spikes or ankylosaur clubs being used upon members of their own kind. However, I can’t imagine it NOT happening.
Well, if you don’t have any biological weaponry on your side, like fangs, horns, spikes, clubs, or whatever, then raw physical force is your go-to option. There is evidence that predator species tangled with prey. The famous fossil find of a Velociraptor and a Protoceratops perpetually locked in a mutual mortal combat proves this. But this is likely an example of an attack-gone-wrong. Did dinosaurs of the same species physically grab onto and grapple with each other? Did dinosaurs wrestle, the way that some lizard species do today? Monitor lizards are a prime example of this, when two males will attack each other by essentially doing reptilian ju jitsu. Did dinosaurs wrestle? I’m not sure, but I’m leaning towards no, especially for the larger ones. Many small dinosaurs had thin delicate bones that could be easily broken, and many of the larger dinosaurs simply did not have the arm dexterity to do rough-and-tumble wrestling maneuvers the way that you see monitor lizards doing today. Furthermore, with their large size, being body-slammed to the ground would have done a lot of damage. As they say, the bigger they are, the harder they fall. Many dinosaurs show signs of physical trauma, including broken bones. Many led a very brutal life, with some skeletons being covered with injuries. For those reasons, I would say that most dinosaurs wanted to avoid intense physical combat.
Sometimes, the violence goes to its absolute extreme, and animals deliberately kill each other. Like intra-species fighting, intra-species killing has several motivating factors, both environmental and social. Animals kill each other to either reduce or totally eliminate competition over limited resources. Animals will also kill rivals to increase their own chances for mating, as well as killing the offspring of rivals to increase their own offspring’s chances for survival. As an example, new male lions that take over an existing pride will often kill all of the pride’s cubs in order to completely eliminate the legacy of the preceding male leader.
The most extreme form of intra-species combat is killing followed by cannibalism. Although it is largely taken for granted that prehistoric carnivorous animals ate their own kind under certain circumstances, there is little evidence to support this hypothesis. Some animals will kill and eat the young of other individuals in order to improve the chances of survival for their own young. Others may kill and eat their own kind out of starvation. Still others, like alligators, may view other members of their own kind as a legitimate food source, no different than any other prey item, and actively hunt, kill, and eat each other.
For a long time, it was believed with the firmest dogmatic conviction that the late Triassic dinosaur Coelophysis practiced cannibalism. However, this long-held belief has come into question upon closer examination of the famous Ghost Ranch specimens. It now appears that many of the bones which were previously believed to be inside the ribcages of others were actually lying underneath the ribcages. Furthermore, some of the bones previously identified as juvenile specimens have recently been re-identified as belonging to other reptile species. For the record, I am not stating that Coelophysis never engaged in cannibalism. I am stating that the evidence for cannibalism in this species is not as clear-cut as once believed and needs to be taken with a certain degree of doubt. If the study of paleontology has taught me anything, it’s that there is no such thing as dogma.
Coelophysis. © Jason R. Abdale. April 26, 2015.
Although there’s questionable evidence for cannibalism in Coelophysis, there is more compelling evidence in another dinosaur from the opposite end of the Mesozoic spectrum – Majungasaurus, an abelisaurid from Madagascar who lived at the very end of the Cretaceous Period. In 2007, scientists published findings that tooth marks discovered on some Majungasaurus bones matched the teeth in Majungasaurus’ jaws. So far, this is the only conclusive proof that a theropod species killed and/or ate the flesh of its own kind. I would like to say one thing, though: just because there’s evidence that an animal was cannibalized, that doesn’t necessarily mean that this individual was killed by the animal feeding off of it. As said before, scavengers will sometimes eat the dead bodies of their own kind. To them, meat is meat, no matter where it comes from. Others will not usually eat their own kind, but will do it if they’re desperate enough and cannot find other sources of food. As an example, most humans who have engaged in cannibalism do it out of necessity, not out of habit.
In conclusion, animals will hurt each other and kill each other for a variety of reasons, not only between species but also within species. Competition for mates, competition for food and territory, and establishing your position within the social hierarchy are all seen within the modern animal kingdom, and it’s highly likely that dinosaurs did the same.
Today, I learned some very heart-breaking news. Stephen Czerkas, one of the true greats of paleo-art, recently died. He was 63 years old. The cause of death was liver cancer.
Czerkas was famous for his life-sized dinosaur sculptures, and he developed a very distinctive style – you could immediately recognize a Czerkas sculpture. His horned Allosaurus graced many children’s dinosaur books and TV shows, and his life-sized Carnotaurus was truly epic. However, his most famous work was his pack of Deinonychus raptors. Czerkas was one of the first paleo-artists to have his theropods adorned with feathers, and he also discovered that at least some species of sauropods had spines on their backs, which was incorporated into the BBC series Walking with Dinosaurs.
To all of those dino-lovers of my generation – those who came of age during the 1990s – Stephen Czerkas’ work would have been an integral part of your life. Czerkas was one of THE paleo-artists of the late 1980s and early 1990s, the time when I was becoming exposed to dinosaurs and other prehistoric life. The sheer awesomeness of his work influenced me profoundly both as an artist and as a person who dedicated his life to studying the past.
The paleontological and artistic spheres have lost one of the true greats of their domain, but his work will last and I dare say will continue to influence artists, scientists, and children generations from now.
RIP Stephen Andrew Czerkas (1951-2015) 😦
A few days ago, scientists announced the discovery of a new species of dinosaur – Acheroraptor, “thief from Acheron”. I’m sorry to disappoint all of you Aliens fans, but no, this dinosaur is NOT named after Planet LV-426, code-named “Acheron”. The name actually refers to the Acheron River in ancient Greek mythology, “the River of Pain”. This name is an obvious pun on the name of the place where the fossils were discovered – the Hell Creek Formation in Montana.
Not much is known about this animal, but here are a few statistics. As you can probabaly guess, Acheroraptor is one of the “raptor” dinosaurs made famous by Jurassic Park. Raptors are divided up into two main groups: the dromaeosaurids and the troodontids. Acheroraptor was a dromaeosaurid, and this brings up another issue…
In an earlier post, I talked about Dromaeosaurus, a dromaeosaurid raptor from western North America. I had stated that its teeth had been found in several different locations, including the Hell Creek Formation. Well, that was perfectly true when I wrote it, but not anymore. For the past few decades, paleontologists had been finding raptor teeth in the HCF, and since they looked similar to the teeth of Dromaeosaurus, these teeth were ascribed to that genus. However, Dromaeosaurus was only known from Canada, and its fossils were found in rocks that were dated much older than the Hell Creek Formation – ten million years older, to be exact. But few other raptor dinosaurs were known from late Cretaceous western North America, and the teeth did look more or less similar to the teeth of Dromaeosaurus, and so that was the identification that was given. Now, paleontologists have discovered that all this time they were perpetuating a case of mistaken identity. It actually happens quite often in this particular science. It appears that the teeth which had been found in the HCF for decades actually belonged to this new species, not Dromaeosaurus.
Acheroraptor’s fossils were found in rocks dated to the extreme end of the Cretaceous Period, 65.5 million years ago, right when the dinosaurs became extinct. It therefore appears that Acheroraptor is the earliest-known raptor, geologically-speaking, being around right up the the point when the asteroid hit.
There are few fossils to go on, consisting of a partial maxilla, a partial dentary, and numerous isolated teeth. Based upon shape and size, paleontologists have determined that Acherorapror was a dromaeosaurid, rather closely related to Velociraptor, and have hypothesized that it may have reached ten feet long. Perhaps in the near future, more fossils will be uncovered which will give us a more complete picture of this animal.
And speaking of pictures, here’s my picture of Acheroraptor! – good segway, right? I further improved the wings from my old Troodon and Ornithomimus drawings, and I made the subject a little more three-dimensional. Rather than standing perfectly sideways, it’s positioned on an angle.
I drew the first sketch when I was giving my English students their final exam on Wednesday December 18, and then I polished off the final product when I got home. I had originally intended it to be a full scene with the dinosaur walking along a forest pathway, but I wanted to get a drawing posted right away, and I just didn’t have the time to make a full Henderson-esque setting.
UPDATE: The original Acheroraptor drawing has been removed, because it was too inaccurate.
The striking black-white color scheme is based upon the coloration of the Northern Goshawk. If this drawing was in color, I would have given my creature transparent glassy red eyes. Making this drawing was a real pleasure, and I’m surprised that doing it didn’t take as long as I had expected – only five days. Keep your pencils sharp!
- Canadian scientists discover new carnivorous dinosaur species Acheroraptor Temertyorum that lived about 66 million years ago (news.nationalpost.com)
- New raptor species named and on display at ROM (metronews.ca)
- Acheroraptor temertyorum: New Dinosaur Discovered in Montana (sci-news.com)
Dromaeosaurus albertensis was a six-foot carnivore which lived in western North America during the Late Cretaceous Period. It is a distant cousin of Deinonychus and Velociraptor. Only one fragmentary skeleton was found in Alberta, Canada, although its teeth have been found in a number of localities, including the Hell Creek Formation. Like many members of Maniraptora, it is believed that Dromaeosaurus had feathers.
This drawing was made using that same time-consuming polygonal scale design that I used on my Giganotosaurus and Troodon drawings. I felt that I should make the scales as small as possible for this guy. Keep your pencils sharp.