Home » Posts tagged 'allosaurid'
Tag Archives: allosaurid
Greetings friends. In an earlier post from 2014, I put up some photographs which I took of the two Allosaurus skeletons that are on public display in the American Museum of Natural History (or AMNH for short) in New York City. I’ve recently uncovered some other photos which I took during a visit there in March 2019, and so I’m posting them here. Enjoy!
Greetings, all. For those who regularly visit this website, you will know that this post has been a long time coming. Years ago, I mentioned that I was planning on re-doing my Allosaurus drawing so that it would be more accurate. However, that project always seemed to be shuffled onto the back-burner in place of other things that I was working on. Well not anymore. I recently completed a detailed drawing of an Allosaurus head (another one of the projects on my to-do list that I never seemed to get around to doing) which you can look at here, and I’m happy to state that after a long delay, I’ve finally completed my updated full-body Allosaurus.
Below is an Allosaurus drawing which I made in July of 2013 and which I posted to this website at that time. This portrays Allosaurus in a color scheme based upon that seen in the 1999 BBC series Walking With Dinosaurs. I must state that, as flawed as this illustration is, this piece was actually itself an updated version of a drawing that I had made a couple of years earlier. Even so, upon reflection, while it was an improvement on my previous work, it still needed more improvement.
And here is my revised Allosaurus drawing, made in July of 2020. This drawing was made in 1:20 scale, which is my preferred scale for illustrating prehistoric animals. From the tip of its nose to the tip of its tail, this drawing measures precisely 21 inches long, which would make the real-life animal 35 feet long; this measurement is regularly given as the maximum size for Allosaurus fragilis. This drawing was made with No.2 pencil on printer paper.
Finally, here is a colorized version of the new drawing. Again, the color scheme is based upon that seen in Walking With Dinosaurs, but the coloration and the color patterns differ slightly from the original image seen at the top. The picture was colored using Crayola colored pencils and No.2 pencil for re-shading.
Nearly everything about my previous drawing was altered in order to make this present artwork. This includes:
- The head was changed to be more accurate in appearance. Designing the head took most of the research time.
- The shape of the eye’s pupil was changed from a sort of oval slit to being a circle.
- The neck was made thicker, more muscular, and not as strongly S-curved.
- The body was made deeper.
- The arms were slightly enlarged and the hands were changed to be more anatomically accurate.
- The legs were thickened to provide extra weight support.
- The orientation of the hip bones was shifted.
- The tail was thickened to provide better balance to the front of the body. The previous drawing was conspicuously front-heavy.
- The tail was slightly elongated.
As you can see, one of the major changes to this drawing was the addition of dermal scutes along its back and sides. Unlike osteoderms, dermal scutes are scales which are enlarged and unusually thick compared to other scales on the rest of the body. There is evidence from preserved skin impressions from stegosaurs and ceratopsians that their skins possessed patterns of dermal scutes, sometimes arranged in lines, and it is therefore possible that theropods had such a feature to their outward appearance as well. It also gives this particular Allosaurus a distinctly reptilian look to it. I decided not to include any type of feathering or some other filamentous structures to the skin.
I also chose to portray this animal in a walking pose rather than running. I think that too many of my drawings of bipedal dinosaurs portray them running Gregory Paul-style, and I wanted to show something more natural. Also, unlike Scott Hartman’s illustrations, the legs are not splayed so widely apart from each other that they’re halfway to performing a split. Mostly, a normal walking stride is about three times the length of the foot. In fact, I actually practiced walking back and forth in front of a mirror, bending my legs theropod-style, in order to get a rough idea of how the leg position on this drawing ought to look.
Keep your pencils sharp, everyone.
Hello everyone. Here is a drawing of the head of Allosaurus fragilis, the top predator of the Morrison Formation of Late Jurassic North America. This drawing has been on my to-do list for quite some time, and I’m happy that it’s finally finished. The drawing was made with No. 2 pencil on printer paper.
This is Camptosaurus dispar, a 20 foot long herbivorous dinosaur from the Morrison Formation of western North America during the late Jurassic Period. In most paleo-art, it seems that the only purpose in life for this unfortunate animal is to be Allosaurus‘ lunch! It’s not hard to see why – a large meaty animal with little or no defenses.
Camptosaurus was a primitive member of the iguanodonts, a group of ornithopod ornithischians which could chew their food. This act helped them to process their food better which in turn helped their digestive systems to extract more nutrients. One of the most well-known features of the iguanodonts was the presence of a thumb spike. On Iguanodon, the thumb spike was rather large. Being a primitive member of the iguanodont family, Camptosaurus also had a thumb spike, but it was comparatively tiny, almost the same size as its other finger claws, and would have been pretty much useless as a weapon. But hey, we all have to start off somewhere.
Paleontologists are still arguing whether Camptosaurus was primarily bipedal or quadrupedal. Personally, while I believe that Camptosaurus was capable of going down on all fours (making it a “facultative quadruped”), I think that it was bipedal most of the time.
Below are three stages of the same drawing: an outline, an outline with the color patterns drawn in, and finally a finished colored drawing. The drawing was made on printer paper with No. 2 pencil, Crayola colored pencils, and Prismacolor colored pencils.
Greetings all. Every child with a rough grasp of what life was like in Late Jurassic North America probably knows the Morrison Formation’s main characters. If such a child were to be asked to name the meat-eaters from that formation, the name Ornitholestes would definitely pop up, likely somewhere around third or fourth place.
Ornitholestes was a 6-foot long coelurosaurid theropod dinosaur that lived in western North America during the late Jurassic Period, 155-145 MYA. It is commonly depicted scampering about in the forest, or along the edge of the forest, or sneakily hiding in the shadows out of sight of the larger predators. With the likes of Allosaurus and Torvosaurus stomping around, it’s easy to see why paleo-artists have relegated little Ornitholestes to a bit-part on the Jurassic stage.
But I like to think that Ornitholestes‘ part was much bigger in the never-ending drama of Mesozoic life. Let’s look at its body. I’ve already stated that it was 6 feet long and was therefore about 2 feet tall – large enough to bite you on the knee. It likely weighed a hundred pounds or a smidge less than that – certainly not more. Its skull is worth looking at. Contrary to what has been commonly portrayed, it DID NOT have a little Ceratosaurus-like crest on the end of its nose. That mistake was made when a dislocated bone was mis-identified as a nasal crest. The skull was thin and deep, like a battle axe, and based upon its structure and that of its neck, it likely had a very strong bite. The teeth are small, but they are rather thick in cross-section. A powerful bite and thick teeth? This makes Ornitholestes sound like a precursor to the tyrannosaurs, and no wonder, because the tyrannosaurs are, in fact, highly-evolved coelurosaurs – the same group that Ornitholestes belonged to. The eye sockets on this baby were huge, so it is likely that Ornitholestes was a nocturnal hunter. As for its body, it was a bit on the muscular stocky side, so it was physically strong. It was equipped with long arms ending in three hook-like claws on each hand, and it had a long tail. We can also be fairly sure that Ornitholestes had a coat of thin whispy fur-like feathers on its body since other coelurosaurids that were more primitive and more advanced that Ornitholestes had feathers.
So what can we determine? It was strong for its size, its jaws could crack through eggshells and small bones, it could run, and it could grapple. In short, Ornitholestes was the hyena of the Jurassic savannah.
Hyenas are nothing to laugh at (I’m sorry, that was bad). Hyenas have a reputation for being scavengers, likely because they are commonly seen picking at the leftovers of the lions’ dinner, and because their jaws are the strongest jaws pound-for-pound of any meat-eating animal on the African plains – good for cracking through thick bones of carcasses. But in reality, hyenas are effective hunters as well. They are pack hunters, like lions or wolves, and it’s not unusual to see a gaggle of them, panting and bare-teethed, running down a zebra or a wildebeest.
Was Ornitholestes the same way? Unfortunately, fossils rarely provide evidence for animal behavior. The fact that Ornitholestes fossils are so rare doesn’t help matters. But I dare say that these carnivorous critters were a serious threat to dinosaur mothers who had eggs to protect, they likely did significant damage to hatchlings, they preyed upon smaller animals like thick-boned mammals, and assuredly were seen scavenging carcasses left by other larger meat-eating dinosaurs.
A while back, I drew a picture of Ornitholestes and posted it to this blog. However, it was an “old school” picture portraying Ornitholestes covered in scales. I have recently made an updated version, and I’m posting that image below.
In addition to the feathers, I’ve also slightly altered the shape of the skull to be a little more accurate. I always try to improve my work, and I dare say that a few years from now after my skills have improved further, I’ll make a drawing of this guy that’s even better than the one you see here.
Keep your pencils sharp, people.
NOTE: The original article concerning Torvosaurus was published on August 8, 2015. It was completely overhauled and re-published on December 9, 2020, with more information and new artwork.
The Morrison Formation of western North America, dated to the late Jurassic Period approximately 155 to 145 million years ago (MYA), is one of the richest fossil beds anywhere on Earth. Ever since the 1870s, the rocks that make up this formation have been intensively studied by paleontologists, geologists, environmental scientists, and amateur fossil hunters. It is from these rocks that hundreds of thousands of dinosaur bones have been uncovered, including the skeletons of some of the most famous dinosaurs ever like Allosaurus, Stegosaurus, and Diplodocus. Their skeletons are on display in museums around the world, and both their names and their physical appearance are instantly recognizable. For some species, so many specimens have been uncovered that we know practically everything that there is to know about their anatomy.
However, not all dinosaur species are so richly attested. There are several species from the Morrison Formation which are known only from one skeleton, or from partial remains, and in some cases from just a single tooth. One of these is a creature which has increasingly gained attention in popular media for the past ten or so years – a large meat-eating dinosaur named Torvosaurus.
Torvosaurus was one of the largest carnivorous dinosaurs that lived in the Morrison Formation. It measured 35 feet long, the same size as its contemporary Allosaurus, nicknamed “the Lion of the Jurassic”. However, there were many anatomical differences between these two species. Torvosaurus and Allosaurus may have lived in the same location at the same time, but Allosaurus was clearly the most numerous theropod within that environment. In fact, we have more fossils of Allosaurus than any other carnivorous dinosaur anywhere in the world. By contrast, very few remains of its competitor Torvosaurus have been found.
Discovery, Phylogeny, and Geographic Diversity
The first fossils of this animal were discovered in 1899 by Elmer Riggs in the “Freeze-out Hills” of southeastern Wyoming, located about eleven miles northwest of the town of Medicine Bow. The material consisted of bones from the left foot and right hand of a meat-eating dinosaur. These fossils were taken to the Field Museum of Natural History in Chicago, Illinois…where they remained untouched, collecting dust in storage, for nearly eighty years, until they were “found” and re-examined. The fossils were officially described in 2013 (Hanson and Makovicky, 2013). It is a tale that is unfortunately common in the realm of natural history museums: specimens are collected in the field, they are brought back to the institution, they are put on a shelf, and then they are completely forgotten about for decades until somebody finds them again. I have personal experience in this.
In 1971 at a place called Calico Gulch Quarry, located in northwestern Colorado, a single gigantic thumb claw was seen sticking out of the ground. Unfortunately, a search of the surrounding area resulted in a dead end – there were no other associated bones nearby (Galton and Jenson, 1979).
A Torvosaurus hand claw. Photo by Matt Heaton, FossilEra (June 3, 2015). Image used with permission. https://imgur.com/ppceR6a. https://www.fossilera.com/blog/torvosaurus-king-of-the-real-jurassic-world-unearthed.
Afterwards, this claw was shown to Prof. Jim Jensen of Brigham Young University in Provo, Utah. In response, the following year in 1972, he and a team of paleontologists turned their attention to a place called Dry Mesa Quarry, a very rich bonebed dated to the late Jurassic which was located in west-central Colorado, in an attempt to find anything that could match the claw that had been found a year earlier. There, they found the partial remains of a large meat-eating dinosaur which Jensen assumed (and that’s the key word here) belonged to the same animal as that enormous claw. The bones which were uncovered were remarkable in many respects, and the team were confident that they had discovered a new species. In 1979, Jim Jensen and his colleague Peter M. Galton published an article concerning this previously-unknown dinosaur, which was officially named Torvosaurus tanneri (“Nathan E. Tanner’s savage lizard”) (Galton and Jenson, 1979).
Fossils of Torvosaurus discovered at Dry Mesa Quarry, housed at Brigham Young University. Photo by Jim Kirkland, posted to Twitter (April 24, 2015). Image used with permission.
A preliminary description of Torvosaurus tanneri was given in Galton and Jenson’s original 1979 report, and subsequent descriptions were published in 1985 and 1991. The last of these studies claimed that the large thumb claw which had been found in 1971 should not be included with the rest of the Torvosaurus remains because it was isolated and found over 150 miles away from the rest of the fossils, and it could not be stated with absolute certainty that they belonged to the same species (Jenson, 1985; Britt, 1991).
Torvosaurus was obviously a meat-eating theropod dinosaur, but where exactly did it fit into the dinosaur tree? In 1985, Jim Jensen assigned this animal to its own family, Torvosauridae, which was intended to include any heavily-built theropod which possessed short-but-powerful arms as well as finger claws that were unusually large in proportion with the overall size of its arms (Jensen, 1985). However, by the late 1980s, it was recognized that Torvosaurus’ hip bones looked remarkably similar to those seen in Megalosaurus, a theropod from the middle Jurassic Period of Europe, and people began to wonder if Torvosaurus itself was a megalosaur; I know of one children’s book dated to 1989 which definitely says that it was (Sattler, 1989). In 1991, Brooks Britt stated that since many of Torvosaurus’ bones were similar to those in Megalosaurus, it therefore ought to be officially re-classified as a megalosaurid (Britt, 1991). It has remained within that theropod family ever since.
By the early 1990s, at least three individuals were identified as belonging to Torvosaurus (two adults and one juvenile) with the remains having been discovered in Wyoming, Utah, and Colorado. No complete specimen of Torvosaurus has been found, so it is difficult to precisely determine its length. However, most sources that I have seen place it as being somewhere between 30 to 35 feet long. Reports which gave a larger measurement of 40 feet or more are believed to have exaggerated its size (Bakker et al, 1992).
Within this article is a detailed drawing which I made of the North American species Torvosaurus tanneri. The drawing was made with No.2 and No.3 pencil on printer paper in 1:20 scale, and it measures 21 inches long, which would make the real-life animal 35 feet long. This illustration is actually the third iteration that I have made of this animal. The first drawing was made back in the middle 2000s when I was an undergrad in college. I knew nothing about Torvosaurus’ anatomy at the time, and all I did was stick a Megalosaurus head onto an Allosaurus body. Not very scientific. My second drawing which I made in 2015 was more in-line with what the animal looked like. However, it was based very heavily on Scott Hartman’s skeletal drawing of this animal, in particular its widely splayed legs, and I definitely did not want to be accused of artistic plagiarism. So, the time came for me to update my work once again. The image that you see here is the finished result based upon what we presently know of the creature’s anatomy.
Torvosaurus tanneri. © Jason R. Abdale (December 5, 2020).
I have also made a colorized version of this animal. I’ve always associated Torvosaurus with the color brown, which I blame on being impressioned by that 1989 children’s book that I read when I was a kid. Consequently, I’ve given it a color scheme of medium brown with a light tan underside and decked out with a camouflage pattern of light tan diamonds framed with black. I’ve also put black feet on it just for some added color contrast.
Torvosaurus tanneri, colorized. © Jason R. Abdale (December 5, 2020).
Torvosaurus comes from a more ancient lineage than Allosaurus. My Allosaurus drawing, which you can see here, was done in a sort of stippling effect to replicate the tiny round scales which have been found associated with Allosaurus skin impressions. Since Torvosaurus comes from an earlier and more primitive line of theropods, I decided to have its primitive nature reflected by giving it large crocodilian-like polygonal scales and rows of decorative dermal scutes. So far, no skin impressions have been found with Torvosaurus, or indeed with any megalosaur to my knowledge, so I cannot be certain if this scale texture is accurate or not.
The scutes on the feet were also changed. I have seen numerous posts on the internet claiming that the rectangular bird-like scutes which are traditionally seen in paleo-art, arranged in rows along the toes and metatarsals of dinosaurs is, in fact, very inaccurate. Therefore, I made these foot scutes smaller, and in so doing, they have taken on a somewhat crocodilian appearance. I must say that it fits with the overall appearance of the animal.
Torvosaurus Fossils in Europe and Africa
For nearly three decades, Torvosaurus fossils had been found exclusively within North America. Then in the year 2000, the bones of a large meat-eating dinosaur were found in Portugal’s Lourinha Formation, also dated to the late Jurassic Period. These fossils looked very similar to those that had been discovered in North America, but there were some slight differences in the anatomy. In 2014, it was officially named Torvosaurus gurneyi. Although known from incomplete remains, it’s evident that the European species has a more boxy skull than its North American counterpart (Hendrickx and Mateus, 2014).
Elsewhere in Europe, isolated fragments which were discovered in England within clay dated to about 155-150 MYA are believed to have come from a megalosaur. Although it was proposed that these fragments might belong to Torvosaurus, it could not be stated with any degree of certainty (Benson & Barrett 2009; Carrano et al. 2012).
In the 2010s, a partial maxilla (one of the bones that forms the upper jaw) was discovered in the Ornatenton Formation in northwestern Germany, at a spot which is not far from the ancient Teutoburg battlefield. An examination of this bone revealed that it was almost identical to the maxillae of Torvosaurus. However, there was one glaring red flag – the Ornatenton Formation occurred millions of years earlier than both the Morrison Formation of the United States and the Lourinha Formation of Portugal. The rock layers of both the Morrison and Lourinha are dated to the Kimmeridgian and Tithonian Stages of the late Jurassic Period, about 155-145 MYA. However, the rocks of the Ornatenton Formation of Germany are dated to the Callovian Stage of the middle Jurassic Period, approximately 166-161 MYA. During this stage, other megalosaur species roamed Europe such as Wiehenvenator, a megalosaur which lived in Germany during that same stage (Rauhut et al, 2016). Therefore, it is possible that this maxilla, which was identified as belonging to Torvosaurus, might be mis-identified. However, a tooth was also discovered within this maxilla, and it is this tooth which is diagnostic. This tooth, in particular the size and pattern of its serrations, does not match those known from either Megalosaurus or Wiehenvenator. A closer examination of the skull fragment showed features which were present in Torvosaurus, but which were absent in other megalosaur genera. Therefore, it is likely that these German fossils belong to an as-yet unconfirmed species of Torvosaurus. This adds further evidence to the idea that megalosaurs like Torvosaurus originated in Europe and then radiated outwards, spreading into North America, Africa, and Asia. It is also possible that the genus Torvosaurus originated in Europe during the middle Jurassic, and then migrated into North America during the late Jurassic. (Rauhut et al, 2020).
In Africa, fossil bones of a large meat-eating dinosaur were found in the Tendaguru Formation of Tanzania, dated to the late Jurassic Period. In 2011, these bones were ascribed as belonging to the super-family Megalosauroidea – it was unclear as to whether it was a megalosaur or a spinosaur (Rauhut, 2011). In 2020, theropod teeth that had been discovered in the Tendaguru Formation, which had formerly been given the unofficial classification of “Megalosaurus ingens”, were ascribed to Torvosaurus, thus potentially creating a third species, Torvosaurus ingens. However, more specimens would need to be collected before this can become officially recognized (Soto et al, 2020)
Torvosaurus in Popular Culture
From its official naming in 1979 up until the early 2010s, Torvosaurus was an obscure species that not many people knew about. Most dinosaur books didn’t even mention it, and the few that did didn’t have that much to say – scarcely a single paragraph in most cases – and much of it was general information that could be given to any theropod dinosaur.
Then in 2011, that changed. That year, the Discovery Channel released a mini-series entitled Dinosaur Revolution, which was intended to be a docu-drama series in the vein of Walking with Dinosaurs, but having a more comic book like feel to it. The second episode, “The Watering Hole”, takes place in Portugal during the late Jurassic Period, and Torvosaurus appeared on screen for the first time. It was portrayed as a massive terrifying beast with a huge head and enormous teeth and was the top predator in its environment. Virtually overnight, Torvosaurus got thrown into the spotlight and its notoriety sky-rocketed.
Comparative Anatomy: Allosaurus fragilis versus Torvosaurus tanneri
Torvosaurus tanneri lived alongside Allosaurus within the Morrison Formation of western North America, but Torvosaurus came from a more primitive line of theropods, the megalosaurs. During the middle Jurassic Period, about 170-160 MYA, these animals ruled the world as the dominant carnivores of their environments. They were the top predators in Europe, Africa, and as far away as China. However, by the late Jurassic, five million years later, these animals were being phased out by newer and more advanced theropods, such as the allosaurs. The megalosaurs had become outdated obsolete relics of a bygone era. By 150 MYA, only a couple of megalosaur species still remained worldwide, Torvosaurus being one of them – all of the others had gone extinct – and it seems that it too was just barely hanging on. By the end of the Jurassic Period five million years later, the last of the megalosaurs would die out.
Both Torvosaurus tanneri and Allosaurus fragilis had the same maximum length of 35 feet or thereabouts, but they possessed different physical proportions. These anatomical differences no doubt drove these two species to develop different hunting styles. Below is an overlay of an Allosaurus (blue) with a Torvosaurus (red) which shows the difference in body proportions. I will be getting into specifics as we go on.
Color contrast between Allosaurus fragilis (blue) and Torvosaurus tanneri (red) © Jason R. Abdale (December 5, 2020).
As a member of the family Megalosauridae, Torvosaurus retained some anatomical features that were primitive compared to more advanced theropods living at that time like Allosaurus. It was also probably less intelligent than Allosaurus as well, although not by much apparently, since Allosaurus wasn’t exactly the brightest bulb either, according to studies of its brain (Allosaurus: A Walking With Dinosaurs Special).
Torvosaurus’ head was much larger in proportion to body size than Allosaurus’ head was. In fact, Torvosaurus’ head was 1.5 times bigger than the biggest Allosaurus skull that we have found. Torvosaurus’ teeth were also freakishly huge, so big that it’s hard to imagine how they could even fit into its mouth. I should state, however, that most museum mounts show Torvosaurus as having much longer teeth than it had in reality because the teeth are extended out of their sockets and half of the root is exposed. Yet even if you were to shorten the teeth to their correct length, the sight is still a fearsome one to behold. Its demonic grinning maw of over-sized steak knives reminds me of the ape-beast “Fluffy” from the 1982 movie Creepshow. By contrast, Allosaurus had very small teeth in proportion to skull size. However, the one thing that both of these animals had in common was the fact that they had flat skulls with sideways-facing eyes. These animals had NO depth perception at all, and they would almost assuredly have to slightly bob their heads back-and-forth from side-to-side, like a shark swimming or a dog scent-tracking, in order to get an alternating left-right-left-right picture of what was in front of them.
Of course, a big heavy head needs a strong neck to hold it up. As such, Torvosaurus’ neck was short and thickly muscular, while Allosaurus’ neck was longer and more sinuous. Allosaurus had the ability to flex its neck to a great degree, especially in an up-down motion (this is known as “ventral flexion”), but the thick layers of muscle on Torvosaurus’ neck would have greatly reduced its mobility.
Torvosaurus had short squat arms and small hands, but the claws are mind-bogglingly massive. When your head is so large and weighs so much, and the majority of your killing power is centered on your jaws, your arms become rather un-necessary. It seems that Torvosaurus was a Jurassic analog of a tyrannosaur, since it had an unusually large head and unusually small arms in proportion to its body. By contrast, Allosaurus also had huge claws, but it also had longer arms and huge hands to go with them; obviously these were used for grabbing and ripping things. Why Torvosaurus, which possessed such short arms, would need such huge claws is beyond my comprehension.
Torvosaurus’ body was long and shallow and possessed an elongated trunk with a low back. By contrast, the body of Allosaurus was short and deep, with a compressed trunk, an arched back, and a deeper ribcage. This is a good body structure for an animal that has a large heart and lungs, indicating an active lifestyle. A small shallow body makes me wonder if a large heavy animal like Torvosaurus ran out of breath quickly. Allosaurus also had large well-built hip bones, which served as attachment points for the muscles that pull the legs back and forth. This means that Allosaurus’ legs were very strong and had the ability to run at full-tilt if it wanted to. By contrast, Torvosaurus’ hip bones were small and not as robustly built – not a design suitable for a runner.
Allosaurus had a tail that was slightly longer than what you would expect when compared with its overall body. This is often given as a definite feature of an agile runner, which needs a long tail to balance the body when it’s making quick tight turns. The tail of Torvosaurus, while long, would probably have to be very thick in order to balance out the weight of the front half of the body. The thick layers of muscle meant that it would not have been able to pivot back-and-forth as easily as the tail of Allosaurus. No tight turns for this beast.
On the whole, Torvosaurus seems to be rather front heavy (good for physically slamming its jaws onto prey) while the weight on Allosaurus appears to be more evenly distributed. Of course, an animal which weighed that much would need some seriously thick legs in order to hold up all of its massive bulk. As such, Torvosaurus’ legs were noticeably thick and robust, far more so than the legs of Allosaurus.
If you look at the detailed picture above, you may think that Torvosaurus’ legs look far too short in proportion with the rest of its body. Surely this was a mistake and the legs ought to be longer, right? Sorry, but the legs are indeed the correct size. It’s true that Torvosaurus’ legs were shorter than Allosaurus’ legs, but they were only slightly shorter. It’s just that Torvosaurus’ head, body, and tail are so utterly huge and massive that the legs look short and under-developed by comparison. It’s an optical illusion. The combination of thick legs, a shallow stretched-out ribcage, and unpronounced hip bones gives Torvosaurus a low-slung appearance. In fact, while I was looking at the entire body, I was struck that Torvosaurus’ build was reminiscent of a rauisuchid. The rauisuchids were a group of archosaurus from the Triassic Period which were related to modern-day crocodiles. Unlike their prestosuchid relatives such as Prestosuchus and Saurosuchus, which were exclusively quadrupedal, the rauisuchids might have been bipedal. The skeletons of rauisuchids such as Postosuchus show a large head, a heavily-built body, short stumpy arms, and short thick legs balanced out by a long tail. The rauisuchids were one of a few groups of non-dinosaurian reptiles which were experimenting with walking on two legs. Torvosaurus’ overall anatomy seems to harken back to an earlier time.
In total, one gets the impression that Torvosaurus was an animal that was not designed for the active chase. It seems that Torvosaurus was primarily an ambush hunter that was built for short-distance bursts, lunging forwards in a straight line, who relied upon its jaws to do most of the work and killing the prey through sheer impact force and by causing deep lacerations with its ungodly-sized choppers. By contrast, Allosaurus was a very active energetic predator who was capable of impressive speed and quick agile turns. If Allosaurus really was “the Lion of the Jurassic”, as it is commonly referred to, then Torvosaurus was the grizzly bear of the Jurassic.
- Sattler, Helen Roney. Tyrannosaurus Rex and its Kin. Illustrated by Joyce Ann Powzyk. New York: Lothrop, Lee, & Shepard Books, 1989.
- Bakker, Robert T.; Siegwarth, James; Kralis, Donald; Filla, James. “Edmarka rex, a new, gigantic theropod dinosaur from the middle Morrison Formation, Late Jurassic of the Como Bluff outcrop region”. Hunteria, volume 2, issue 9 (1992). Pages 1-24.
- Benson, Roger B. J.; Barrett, Paul M. 2009: “Dinosaurs of Dorset: Part I, the carnivorous dinosaurs (Saurischia, Theropoda)”. Proceedings of the Dorset Natural History and Archaeological Society, volume 130 (2009). Pages 133-147.
- Britt, Brooks. “Theropods of Dry Mesa Quarry (Morrison Formation, Late Jurassic), Colorado, with emphasis on the osteology of Torvosaurus tanneri”. Brigham Young University Geology Studies, volume 37 (1991). Pages 1-72. http://geology.byu.edu/home/sites/default/files/geol-stud-vol-37-britt.pdf.
- Carrano, Matthew T.; Benson, Roger B. J.; Sampson, Scott D. “The phylogeny of Tetanurae (Dinosauria: Theropoda)”. Journal of Systematic Palaeontology, volume 10, issue 2 (2012). Pages 211-300.
- Galton, Peter Malcolm; Jensen, James A. “A new large theropod dinosaur from the Upper Jurassic of Colorado”. Brigham Young University Geology Studies, volume 26, issue 1 (1979). Pages 1-12. geo-stud-vol-26-part-2-galton-jensen.pdf (byu.edu).
- Hanson, Michael; Makovicky, Peter J. “A new specimen of Torvosaurus tanneri originally collected by Elmer Riggs”. Historical Biology, volume 26, issue 6 (2014). Pages 775-784. https://www.tandfonline.com/doi/abs/10.1080/08912963.2013.853056?scroll=top&needAccess=true&journalCode=ghbi20.
- Hendrickx, Christophe; Mateus, Octavio. “Torvosaurus gurneyi n. sp., the Largest Terrestrial Predator from Europe, and a Proposed Terminology of the Maxilla Anatomy in Nonavian Theropods”. PLOS One, volume 9, issue 3 (2014). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3943790/.
- Jensen, James A. “Uncompahgre dinosaur fauna: A preliminary report”. Great Basin Naturalist, volume 45, issue 4 (1985). https://scholarsarchive.byu.edu/gbn/vol45/iss4/8/.
- Rauhut, Oliver W. M. “Theropod dinosaurs from the Late Jurassic of Tendaguru (Tanzania)”. Special Papers in Palaeontology, volume 86 (2011). Pages 195-239.
- Rauhut, Oliver W. M.; Hübner, Tom R.; Lanser, Klaus-Peter. “A new megalosaurid theropod dinosaur from the late Middle Jurassic (Callovian) of north-western Germany: Implications for theropod evolution and faunal turnover in the Jurassic”. Palaeontologia Electronica, 19.2.26A (2016). Pages 1-65.
- Rauhut, Oliver W. M.; Schwermann, Achim H.; Hübner, Tom R.; Lanser, Klaus-Peter. “The oldest record of the genus Torvosaurus (Theropoda: Megalosauridae) from the Callovian Ornatenton Formation of north-western Germany”. Geologie und Paläontologie in Westfalen, volume 93 (2020). Pages 1-13. https://www.lwl.org/wmfn-download/Geologie_und_Palaeontologie_in_Westfalen/GuP_Heft_93_14_Seiten.pdf.
- Soto, Matías; Toriño, Pablo; Perea, Daniel. “A large sized megalosaurid (Theropoda, Tetanurae) from the Late Jurassic of Uruguay and Tanzania”. Journal of South American Earth Sciences, volume 98 (2020): 102458.
- Allosaurus: A Walking With Dinosaurs Special. BBC, 2000.
- Dinosaur Revolution. Episode 2 – “The Watering Hole”. The Discovery Channel, 2011.
Well, it was that time of year again! Every April or so, at around the time of Easter, the Garvies Point Museum and Preserve, located in Glen Cove, Nassau County, New York, holds it annual “Dinosaur Day”. This is one of the days that I really look foward to for a few reasons. First, I get to work at a place that I absolutely love and meet with some good friends. Secondly, I get to be out of NYC for a little while, which is something that I ALWAYS look foward to. Third, I get to talk about a subject that has fascinated me since my earliest days – paleontology.
Veronica, the museum’s de facto head of administration, did a wonderful job along with other members of the museum staff of setting up the classroom where the day’s major activities would be taking place. Recently, the museum’s library was substantially increased. The Sands Point Museum and Preserve had closed down its library a short while ago, and all of the books and papers were sent to the GPM. I should state, though, that almost all of these documents were originally part of the GPM collections anyway, and they just got them back, that’s all. However, Louis (one of the workers at the Garvies Point Museum, but works primarily at the Old Bethpage Village – another place that I really love) has been working hard to re-catalogue all of these books and papers back into the museum’s database.
The name of the event was somewhat misleading, as it concerned all prehistoric life, not just dinosaurs. We had exhibits on primitive mammal-like-reptiles, dinosaurs, and prehistoric mammals.
Here are some pictures of what the room looked like both during and after the hoards of kids showed up.
Most of the really young children gravitated immediately towards the dino toy area and the fossil digsite. The older children and a lot of the adults were interested in the information that I and others were giving. They were especially interested in Dimetrodon, the famous sail-backed pelycosaur from the early Permian Period. I don’t think that I have ever had to say the name”Dimetrodon” so many times within the course of a single day! It seemed to be the only thing that many of them wanted to talk about!
Some of the major topics of interest on this day were: the Permian Mass Extinction, which occured about 251 million years ago, when an estimate 95% of all life was wiped out; of course, T. rex was a favorite; as too was Allosaurus, who competed with its larger relative for attention from the crowds. This was helped in no small part to the fact that we had a lot of Allosaurus “stuff” arrayed for them: a picture of the skull, a hand model, bone casts, a model, and my drawing which you might recognize from an earlier post on this blog.
Finally, here’s a picture of me, “the Dinosaur Man” as several members of the museum staff call me, dressed up as an amateur paleontologist. In addition to my olive drab Garvies Point Museum shirt, I also wore a khaki utility vest, because apparently ALL paleontologists wear khaki utility vests! I thought that wearing it would help to enhance my ethos with the audience, and by my reckoning, it worked.
Here’s a drawing that I did a while ago, but for some reason, my computer screwed it up. It’s only recently that I’ve re-scanned it and fixed it up.
Camarasaurus was the most common sauropod dinosaur within the Morrison Formation of western North America during the late Jurassic Period. Other species like Apatosaurus and Diplodocus might be more familiar to the ear, but in terms of the sheer numbers of specimens that have been found, this big guy tops the list. As far as size goes, it was a tad on the small side for a sauropod, measuring only 60 feet long. Its relatively small size (that is, compared with the other larger sauropods that it shared its habitat with) and meaty build likely made it one of the preferred targets for a mob of Allosaurus to take down. The reason why Camarasaurus was the most common species of its kind might be due partly to its smaller-than-average size (smaller stomachs mean more food to go around for everyone, and by extent leads to having larger populations) and partly to its apparently generalistic diet. Creatures which have a specialized diet are often hit hard when catastrophies arise, whereas dinosaurs that are more adaptable and flexible in terms of what they eat come out more favorably.
Many times, you’ll see these dinosaurs illustrated Gregory Paul-style, with thin spindly legs. I decided that the biomechanics of this simply weren’t feasible, and so I gave my animal suitably thicker more elephant-like legs, able to hold up the tens of tons of weight. Also notice that, contrary to other artistic renderings of this species, the neck is NOT held straight vertically upright, but is thrust more forwards in a 45 degree S-shaped curve. This is also one of the few dinosaur drawings that I’ve done in color. In terms of the color pattern, I’ve always imagined Camarasaurus colored in the scheme that you see above, even as a little kid – tan body with broad brown stripes and a somewhat yellowish-tan underbelly. I simply cannot imagine this species colored in any other way.
Keep your pencils sharp, people.
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) 😦
Hot off the presses! A new carnivorous dinosaur from Portugal has been officially named – Torvosaurus gurneyi.
The fact that Torvosaurus came from Portugal isn’t a revelation – it was, after all, featured prominently in an episode of the Discovery Channel mini-series Dinosaur Revolution (which I didn’t particularly care for). For years, people have known that there have been megalosaurid dinosaur fossils from Portugal, specifically the Lourinha Formation, which dates to the late Jurassic Period, about 150 million years ago. These fossils were tentatively ascribed to the species Torvosaurus tanneri, known from the Morrison Formation of the USA. However, upon closer examination, there are a few minor differences in the bone structure, so the Portuguese specimens were named Torvosaurus gurneyi, named after the famous paleo-artist James Gurney.
Torvosaurus was one of the last megalosaurid theropods, as they were being replaced by the allosaurids and the coelurosaurids. Torvosaurus and its kind ruled Europe during the middle and late Jurassic Period. It measured 30-35 feet long, giving Allosaurus a serious run for its money, and possibly weighed somewhere in the realm of four to five tons.
As if this wasn’t news enough, there are some dinosaur embryos from Portugal which might belong to Torvosaurus as well.
For more info, check out the websites listed below:
- SciNews.com. “Torvosaurus gurneyi: New Giant Dinosaur Discovered in Portugal” (March 6, 2014). http://www.sci-news.com/paleontology/science-torvosaurus-gurneyi-giant-dinosaur-portugal-01794.html
- National Geographic Daily News. “Largest Predatory Dinosaur in Europe Found, Was ‘Big Bruiser'”, by Christine Dell’Amore (March 5, 2014). http://news.nationalgeographic.com/news/2014/03/140305-dinosaurs-biggest-europe-torvosaurus-gurneyi-animals-science/
- Nature. “Filling the gaps of dinosaur eggshell phylogeny: Late Jurassic theropod clutch with embryos from Portugal”, by Ricardo Araújo et al (May 30, 2013). http://www.nature.com/srep/2013/130530/srep01924/full/srep01924.html