Many times, paleo-artists take a feature that was found in a few species and ascribe it to entire groups. One of these trends is to portray osteoderms on the bodies of dinosaurs in their artwork. The word osteoderm literally means “skin bone”. These are small pieces of bone which are embedded in the skin, and sometimes protrude out of it so that they look like bony bumps on the dinosaur’s body. Evidence suggests that they were often covered with a keratinous scute. The most prevalent example of dinosaurs possessing osteoderms is a group called the thyreophorans, meaning “shield-bearers”, which includes the stegosaurs and ankylosaurs, but other dinosaurs have them too. At least one titanosaurid sauropod, Saltasaurus, has been found with osteoderms, and it is believed that possibly all titanosaurs had osteoderms as well.
One contentious issue regarding osteoderms is their presence in theropods, or rather, in artwork depicting theropods. There is a tendency among paleo-artists to adorn the bodies of theropod dinosaurs with rows of small osteoderms along their neck, back, and tail, and I too have been guilty of this practice. However, as far as I am aware, only two theropod dinosaurs have been found with osteoderms: Ceratosaurus (western USA and possibly Africa, Late Jurassic) and Carnotaurus (Argentina, Late Cretaceous). Both of these dinosaurs were, cladistically-speaking, primitive, and were probably closer both in appearance and genetics (and almost assuredly intelligence) to early primitive archosaurs than to later theropod groups.
In terms of appearance, Ceratosaurus was found with a single row of small osteoderms running down the middle of its back (NOT multiple parallel rows, as is often shown in some works of paleo-art), extending from the back of the skull and running all the way down to the tip of the tail. Carnotaurus was found with excellent skin impressions on portions of the body, and these showed that the body was covered in non-overlapping reptilian scales, not feathers. The scales themselves were irregular in pattern and arrangement, with some being larger and more pronounced than others. Also, on the back were arranged several parallel rows of osteoderms, spaced at regular intervals. The osteoderms became larger the closer they were to the middle of the body (medially).
In terms of cladistics, Ceratosaurus and Carnotaurus belong to the same group of theropod dinosaurs, Ceratosauria. Specifically, Ceratosaurus is a ceratosaurid and Carnotaurus is an abelisaurid, which is a slightly more advanced line. It may be possible that all theropods within Ceratosauria were adorned with osteoderms, but we cannot be 100% certain of this. However, as I said earlier, some paleo-artists have a tendency of taking a feature found in one or a few specific animals and ascribing this feature to the entire sub-group of dinosaurs. For example, a few paleontologists and paleo-artists believe that many and perhaps all sauropods had a row of keratinous spines running down the neck, back, and tail just because ONE specimen of Diplodocus was found with them. While this proves that this particular species and possibly the genus had this feature, it does not mean that all diplodocid sauropods had these keratinous spines, and it certainly doesn’t prove that all sauropods in general had this feature. The same goes for theropods. Many paleo-artists place osteoderms on their meat-eating dinosaur’s bodies simply because osteoderms have been found in association with two carnivores, and they decided to put them on virtually every theropod that they drew or sculpted.
Extrapolation is no sin. There’s nothing wrong about making an observation about something and suggesting that something else which was similar may have had identical properties. Writers and researchers do it all the time. However, I should warn people out there that there are varying degrees of extrapolation. It’s one thing to make an observation based upon the fossils of these two dinosaurs, which, as I stated before, came from the same theropod sub-division, and assume or hypothesize that other species within this particular group may have had this feature as well. It is quite another thing to take that feature and apply it to every theropod genus from Eoraptor to Velociraptor.
But what about “scutes” on dinosaurs? The term “scute” has two definitions: either it is the scale-like covering over an osteoderm, or it’s simply an unusually large thick scale. Preserved skin impressions from multiple species have shown that some dinosaurs had rows of large, thick, texturally-pronounced scutes arranged on their bodies, but these scutes did not have a bony core – therefore they can’t be classified as “osteoderms”. Examples of animals that have this feature are the stegosaur Hesperosaurus and the ceratopsian Chasmosaurus.
I may sound like I’m being self-righteous and pontificating, but I too am guilty of making wild extrapolations and assumptions when it comes to my prehistoric illustrations. A few years ago, I did an anatomical study of Tyrannosaurus rex in a running pose, and I had it with osteoderms, for no other reason other than so many other paleo-artists had pictured T. rex with osteoderms in the past. I followed the crowd and illustrated my T. rex accordingly. However, later on when I read about tyrannosaur skin impressions, I learned that these large tyrannosaurs had small pebbly skin with no osteoderms. Consequently, I revised my drawing, which you can see here.
Another example of where I might have made a mistake is in my drawing “Giganotosaurus head study”, which was showcased in an earlier post on my blog; you can see it here. The reason why I had put those rows of bony bumps on its neck and a few on its jaw was because at the time I thought that Giganotosaurus was an abelisaurid, which is a sub-division of Ceratosauria. I later learned that it wasn’t, but I didn’t want to change the picture – I think it looks nice as it is. However, I’ll be sure to learn all of the information that I can about a certain subject in the future before I draw it.
What I’m trying to do here is caution paleo-artists and aspiring paleo-artists about the dangers of making wild assumptions and extrapolations. Do your homework, do your research, and illustrate your creations as best as current science allows, and don’t do anything that you aren’t able to back up with researched facts and/or persuasive arguments.
Keep your pencils sharp.
This is one of the pictures which appears in my book. It is a map of the various tribes which existed in ancient Germania at around the year 15 BC. The picture that’s shown in the book is a little too small, so here’s a larger version for you to look at. Some of the names are abbreviated:
AMP = Ampsivarians
ANG = Angrivarians
CHAS = Chasuarians
DULG = Dulgubini
SIC = Sicambri
USI = Usipetes
VAN = Vangiones
This is probably the most accurate map that you’re going to find for ancient Germanic barbarians during the last years of the 1st Century BC.
Pterosaurs were prehistoric winged reptiles distantly related to the dinosaurs – they were NOT actually flying dinosaurs, despite what some people might tell you. Pterosaurs are broadly catergorized into two biological groups called “sub-orders”: the pterodactyloids (this is where the word “pterodactyl” comes from) and the rhamphorhynchoids. They came in all shapes and sizes, from sparrow-sized ones to creatures as large as fighter jets.
The Mesozoic Era, the geologic time frame when dinosaurs lived, is divided up into three “periods”: the Triassic Period, the Jurassic Period, and the Cretaceous Period. Pterosaurs first appeared towards the end of the Triassic Period, and likely evolved from small tree-dwelling gliding reptiles.
The pterosaur depicted in this blog post’s associated image comes from the late Jurassic Period. One of the best places to find fossils dated to this time is in western North America, and it is referred to as the Morrison Formation – a layer of rock stretching throughout much of Utah, Wyoming, and Colorado where fossils of dinosaurs and other prehistoric creatures have been found dated to the late Jurassic, spanning from 155-145 MYA.
The pterosaur that you see here is named Dermodactylus montanus. It was a small pterodactyloid pterosaur with a 3-foot wingspan, about the size of a hawk. So far, the only fossil collected of this species was a single finger bone found in 1878. No other pterosaur fossils found within the Morrison Formation have been ascribed to this genus since then. Many paleontologists today classify Dermodactylus as a nomen dubium – a classification used when scientists aren’t sure if a certain species or genus actually existed. The finger bone in question might have come from another pterosaur, and was misidentified.
If you want to know more about pterosaurs, I highly suggest you check out the WordPress blog “Archosaur Musings”, run by British paleontologist Dave Hone.
Also, check out Mark Witton’s (another British pterosaur expert) blog:
Let’s change from dinosaurs to some other prehistoric life. Here are two prehistoric sharks. The large gray one on top is called Cretoxyrhina mantelli, more commonly known as the Ginsu Shark. The smaller blue one underneath is called Squalicorax falcatus, more commonly known as the Crow Shark. These two species are only a handful of prehistoric animals that have common names ascribed to them – most paleo-critters have only their scientific names.
Both of these prehistoric sharks lived in what was called the Niobrara Sea, also called the Western Interior Sea, which covered the central third of North America during the late Cretaceous Period. Both of these sharks are classified as being lamniform sharks, also known as mackerel sharks. This is the same group which includes the Mako and the Great White. “Modern” sharks first appeared on Earth towards the end of the Mesozoic Era, and both of these species are good examples of early modern sharks.
Cretoxyrhina was a large twenty-foot shark. It lasted from 100-82 MYA, and it was probably the top predator in its environment during that time. However, during the Cretaceous Period, a new group of marine carnivores appeared called mosasaurs. These creatures were literally oceanic lizards – in fact, their closest relatives are today’s monitor lizards, like the ten-foot Komodo Dragon. But mosasaurs got much bigger than this, with some reaching over forty feet long. The mososaurs out-competed this large shark for food and drove it into extinction.
The smaller Crow Shark appears to have been much more versatile. It evolved into several different species, some measuring six feet long, while others reached as high as sixteen feet in length.
One of the things that you’ll immediately notice about this drawing is that it’s in color. I very rarely make color drawings – I usually just stick to grayscale. The reason why is because I haven’t really gotten the knack for making illustrations in color yet. I’ve been working in black-and-white for a long time, and I dare say (at the risk of tooting my own horn) that I’ve gotten pretty good at it. I don’t like using color because it washes out all of the texture and detail. Well, it’s a learning process. I’m sure that I’ll get the hang of it sooner or later.
Keep your pencils sharp.
This was the first illustration that I made which was actually published. I drew this last year for Prehistoric Times Magazine, and it was accepted by Mr. Michael Fredericks, the magazine’s editor. It appeared in print in issue #102 (Summer 2012). Needless to say, I was excited when I was told that one of my drawings would appear in a magazine. I was even more excited when I actually saw it in print. Giganotosaurus carolinii lived in Argentina about 100 million years ago (or MYA as it is commonly abbreviated) during the middle Cretaceous Period. Giganotosaurus, which means “giant southern lizard”, was slightly larger than T. rex, but it also evolved from a more primitive ancestry. Because it was more evolutionarilly primitive than T. rex, I wanted to give it more crocodile-like skin. This drawing took me three whole weeks to complete, working non-stop. By contrast, my “Tyrannosaurus rex head” drawing, which is equally detailed and is the same size, only took me three days. Why did this drawing take so long? It’s because each scale had to be drawn individually and given special individual attention.
I have an interesting quirk when it comes to illustrating creatures with this type of skin texture. I use regular copy paper for most of my drawings. It may look smooth, but if you get really up close to it, you can see that it actually has a rather rough and imperfect surface – it is covered in very small wrinkles and dents. The human eye and brain has a tendency to recognize patterns, whether they actually exist in reality or not. When I saw the dents and wrinkles in the paper, my eye simply connected the dots. The result is what you see. This is why many of the scales, if you examine them closely, have facets with straight sides. It’s a very time-consuming process, but it produces great effects. I love all of my drawings, but this one is definitely one of my favorites, and I’m sure that it will be one of your favorites as well.
This was a drawing that I made to accompany my “Tyrannosaurus rex head” drawing. It shows a pair of T. rexes pursuing and attacking an Alamosaurus. This is something that is rarely seen in Tyrannosaurus paleo-art. Usually, the large carnivore is seen attacking a Triceratops or a hadrosaur. I’ve only seen a handful of examples where a T. rex is attacking an Alamosaurus. Alamosaurus was a titanosaurid sauropod which inhabited the southern part of North America during the Late Cretaceous. As far as I am aware, it was also the only sauropod existing in North America during this time. Contrary to what nearly everyone thinks, it is NOT named after the Alamo in Texas, but this is a side-point. I wanted to “raise the population”, so to speak, of illustrations depicting a clash between these two large North American dinosaurs. I hope you enjoy it.
I have been drawing dinosaurs ever since I was 2, but this was the first drawing that I ever did professionally. It was a pencil illustration of a Tyrannosaurus rex‘s head, which I finished on March 16, 2012, and submitted to the Lazendorf Paleoart Contest. Unfortunately I didn’t win. Still, I am very proud of this particular piece, and I felt that it would be fitting to have this drawing as the first of my artworks displayed on my blog.
Before I get underway posting any of my material, I have a few things to say. This blog, like every other blog, is considered a publication, just the same as a book, magazine, journal, or newspaper. Unless stated otherwise, anything that I post on this blog, be it text or pictures, is considered to be my personal property. If I want to include pictures or quotations from other sources in my writings, I need to write down where I got the material from, which includes crediting the original author or artist. Using someone else’s material without citing it as belonging to the original author/publisher/artist is considered an act of plagiarism and theft, and there may be legal consequences. This is especially true if you are making money off of your work.
As you can see, I take this sort of thing very seriously, so don’t do anything stupid. Forgive me if I sound a bit stern, but I want to be very clear about this before I progress any further with this blog so that people know where I stand and what they need to do if they want to use my material. If anybody out there wants to use my artwork or my writings, please contact me about it beforehand.
That being said, I hope that you find my posts entertaining and informative. I look forward to any academic or artistic feedback regarding my work. Take care.
My name is Jason R. Abdale. I have a bachelor’s degree cum laude and a master’s degree in history, both of which I received at Queens College in 2008 and 2009 respectively. In terms of history, my specialty area is tribal history and culture, but I am also highly knowledgeable in ancient, medieval, European, early American, and military history. I have a self-taught background in other academic areas, such as anthropology, zoology, and paleontology.
My first love always was and always will be the past, whether it is the human past or the natural past. Paleontology has always been a big part of my life. I got into dinosaurs when I was 2, and I have been unrepentantly addicted ever since. I have been drawing prehistoric life for the same amount of time, but I only began doing it professionally from 2012 onwards. Some of my artwork has been published in Prehistoric Times Magazine and has been on display in museums in the United States, Canada, and China.
My research, writing, and analytical skills were considered to be highly exceptional by my professors. For my graduate thesis, I wrote a biographical essay about an Indian leader named Tanaghrisson, commonly known as the Half-King, who played a significant role in starting the French and Indian War. My status as a specialist in tribal history and culture eventually landed me a temporary internship with the Anthropology Division at the American Museum of Natural History.
I currently teach at Vaughn College, which is an engineering school devoted to aircraft and aeronautics. Here, I teach courses in English, history, and political science.
I have written a history book entitled Four Days in September: The Battle of Teutoburg, concerning a battle fought between Rome and the Germanic barbarians in late September of 9 AD. It was published by Trafford Publishing in 2013, and a second edition was published by Pen & Sword Books in 2016. In 2019, my second history book, The Great Illyrian Revolt, was published by Pen & Sword Books.
Anyway, that’s my story. Welcome to my blog, entitled after my two favorite subjects, “Dinosaurs and Barbarians”. Here, you will find examples of my artwork and my writings concerning both history and prehistory. These are meant to be commented upon, and I look forward to any academic or artistic feedback. Take care, and keep your pencils sharp.
Hello everybody out there! My name is Jason R. Abdale. I am an artist and historian, and I want to welcome all of you to my blog “Dinosaurs and Barbarians”, named after my two favorite subjects of study. I intend to use this blog as a showcase for my artwork and for various hypotheses that I have pertaining to history and prehistory. I trust that you will find the content of my blog interesting and informative, and I look foward to your commentary.