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This is Caturus, a prehistoric fish which swam in the oceans during the Mesozoic Era. Fossils of this saltwater fish have been found in North America, Europe, northern Africa, and as far as China within rocks spanning from the beginning of the Triassic Period about 250 MYA up to the middle of the Cretaceous Period, about 100 MYA. However, most fossils have been found in Europe in rock layers dated to the middle and late Jurassic Period, about 170-150 MYA.

Despite a superficial resemblance to a salmon, Caturus was actually more closely related to a bowfin (Amia calva), which is a rather primitive ray-finned fish.

So far, paleontologists have identified fourteen species of Caturus. The largest species, Caturus furcatus, which lived in the shallow sea that covered much of Europe during the late Jurassic period about 150 MYA, reached three feet long; other species were much smaller. One species, Caturus dartoni, is known from North America in rocks dated to the middle Jurassic, about 165 MYA. Only two skeletons of this particular species have been found, the largest measuring 15 inches long.

Caturus. © Jason R. Abdale. September 5, 2020.

This drawing was made on printer paper with No.2 pencil, No.3 pencil, Crayola colored pencils, Prismacolor colored pencils, and Artist’s Loft colored pencils.


Hello everyone. Several years ago, I wrote a short article for Prehistoric Times magazine about the Sundance Sea. This was a shallow saltwater sea which covered much of central North America during the middle to late Jurassic Period. One of the illustrations that I made which accompanied that article was a drawing of a pair of plesiosaurs chasing after a school of belemnites. The plesiosaurs in question were called Pantosaurus. This species was a member of the “cryptoclidid” family of plesiosaurs, and measured about 20 feet long.

I thought that I had posted that drawing onto this website at that time, but looking through my portfolio, it appears that I neglected to do so. Well, better late than never! Unlike many of my other drawings, which are mostly made with No.2 pencil or colored pencils, this one was made with a black ballpoint pen and a black marker.

Pantosaurus with belemnites. © Jason R. Abdale. November 18, 2014.


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This is Baptanodon, an ichthyosaur which lived during the middle and late parts of the Jurassic Period about 165-155 million years ago. During this time, the central part of North America was covered with a body of saltwater known as the Sundance Sea, and Baptanodon was one of the creatures that swam in this inland ocean. It measured 20 feet long, it had freakishly huge eyes, and, as far as I have been able to learn so far, it had small teeth only in the front half of its mouth while the rear half was completely toothless. The presence of grooves running along the sides of its jaws indicate that it probably had lips and the teeth would not have been visible when the mouth was closed.

Baptanodon was closely related to the European ichthyosaur Ophthalmosaurus. In fact, for a while it was believed that Ophthalmosaurus and Baptanodon might be the same animal. However, phylogenic studies indicate that they are indeed separate.

Baptanodon shared its habitat with numerous other forms of marine life including oysters, ammonites, belemnites, hybodont sharks, as well as the 20 foot long plesiosaur Pantosaurus and the 25 foot long pliosaur Megalneusaurus.

This drawing was made on printer paper with No.2 pencil, Crayola colored pencils, and Prismacolor colored pencils.

Baptanodon. © Jason R. Abdale. August 12, 2020.

Champsosaurus: The Croc-Lizard of the Cretaceous

When most people hear the words “aquatic reptile”, they usually think of two things: turtles and crocodilians. Some clever people might mention sea snakes, and others might mention marine iguanas. Those who are keen on impressing you may bring up some obscure species like the water monitor, the basilisk lizard, and other species of snakes which venture into water.

In prehistoric times, the list of options that you could choose from was much more expansive. In fact, there were animals around then which aren’t around today which fit into this category. One such group of prehistoric water-going reptiles was known as the “choristoderans” (pronounced as Kore-RISS-toe-DEER-rans).

The choristoderans were a group of semi-aquatic reptiles which lived during the Mesozoic Era. Although not as well-known as other non-dinosaurian reptiles of the Mesozoic such as pterosaurs and ichthyosaurs, they nevertheless shared their environments with dinosaurs for a span of approximately 110 million years and even survived the dinosaur extinction. Choristoderans first appeared during the middle of the Jurassic Period about 175 MYA. The oldest-known genus which is recognizably a choristoderan was Cteniogenys, which measured just one and a half feet long and was very lizard-like in appearance. In life, it probably resembled a small monitor lizard and it likely filled a similar ecological niche. However, the heyday for the choristoderans occurred during the early Cretaceous Period from about 144 to 100 MYA, after which they went into decline. They were fortunate to survive the K-T Extinction, but they were always second fiddle to their crocodile neighbors. Most of the surviving species went extinct about 50 MYA, with the remainder just barely hanging on. The last of the choristoderans completely went extinct around 20 MYA.

The choristoderans belonged to a group of vertebrates called the “diapsids”, meaning that they had two holes in their skull behind each eye socket. Lizards, snakes, crocodilians, pterosaurs, dinosaurs, and birds are all classified as diapsids.

At first glance, choristoderans might be mistaken for crocodiles. However, despite their crocodile-like appearance, they are more closely related to lizards than to crocodiles, at least according to a study made by Mike Lee in 2013 (“Turtle origins: insights from phylogenetic retrofitting and molecular scaffolds”). Their placement in the reptile tree is primarily based upon the structure and arrangement of their ear bones, which is more advanced than those seen in lizards but not as advanced as those seen in crocodilians and birds. Also, the skulls of choristoderans are structurally more lizard-like than crocodilian.

The order Choristodera is divided into four families: Champsosauridae, Hyphalosauridae, Monjurosuchidae, and Simoedosauridae. The more primitive the species, the more lizard-like it is in form. The more derived, then the more crocodilian it is in appearance. The most primitive choristoderans were the monjurosuchids, which looked similar to the modern-day Water Monitor Lizard (Varanus salvator). Even at this early stage in their development, there is fossil evidence that some species like Monjurosuchus possessed webbed fingers and toes. Already, they were adapted to living a semi-aquatic lifestyle.

Skeleton of Monjurosuchus splendens, a primitive choristoderan from China. Photograph by Jonathan Chen (June 13, 2019). Creative Commons Attribution-Share Alike 4.0 International license. https://commons.wikimedia.org/wiki/File:Monjurosuchus-Beijing_Museum_of_Natural_History.jpg

Even more advanced were the hyphalosaurids, which bear a remarkable resemblance to the earlier nothosaurs and thalattosaurs of the Triassic Period. Form tends to follow function in evolution, and these creatures almost certainly led a similar lifestyle. The act of species from completely different groups evolving into more-or-less the same shape is called “convergent evolution”.

The champsosaurids and the simoedosaurids are the most crocodile-like in appearance, and together they form the super-family Neochoristodera. Like crocodiles, these creatures were almost certainly living as shallow-water ambush predators, fitted with long slender jaws lined with small conical teeth. Like modern-day gharials, they may have been primarily or even exclusively fish-eaters.

Probably the most famous choristoderan genus was Champsosaurus (pronounced as CHAMP-so-SORE-us). It first appeared about 90 MYA during the Turonian Stage of the late Cretaceous Period, persisted through the K-T Extinction, and finally went extinct during the Paleocene Epoch of the Tertiary Period about 56 MYA. Impressive. Most genera don’t last that long.

Champsosaurus was named by the famed paleontologist Edward D. Cope in the year 1877. Despite not having an easily-recognizable name (most members of the general public have likely never heard of it), it has been rigorously studied by paleontologists ever since then. For example, three academic articles were published about it just in the year 2010, and another article was recently published in April 2020. So, from an academic standpoint, interest in this animal has been pretty consistent.

There are seven species which have been ascribed to the genus Champsosaurus. Most of them measured 5 feet long or thereabouts, but the largest, which was appropriately named Champsosaurus gigas, reached 10 feet long. Most Champsosaurus fossils have been found in south-central Canada and the north-central United States within rocks dated to the late Cretaceous Period from 90 to 66 MYA, but a few have also been found in Belgium and northern France in rocks dated to the Tertiary Period.

Champsosaurus skeleton from Montana, USA on display in the Royal Ontario Museum. Photograph by Daderot (November 21, 2011). Public domain image, Wikimedia Commons. https://commons.wikimedia.org/wiki/File:Champsosaurus_sp.,_Montana,_USA,_Late_Cretaceous_-_Royal_Ontario_Museum_-_DSC00088.JPG.


Upper jaw of Champsosaurus, above view (left) and underside view (right). The skull’s length measures about 13 inches. Illustration by Samuel W. Williston. From The Osteology of the Reptiles (1925). Public domain image, Wikimedia Commons. https://commons.wikimedia.org/wiki/File:The_Osteology_of_the_Reptiles_p76.png.

Champsosaurus appears to have been able to tolerate both freshwater and saltwater environments. Fossils of a species called Champsosaurus laramiensis have been found in rocks from the Fox Hills Formation, a geological layer which represents a coastal or estuary environment on the edge of the Western Interior Sea. Fossils of mosasaurs and dinosaurs including Tyrannosaurus have also been found in these rocks.

Preserved skin impressions show that, unlike many lizards, choristoderans like Champsosaurus did NOT have overlapping scales. Instead, the skin consisted of tiny non-overlapping scales, with no crocodile-like dorsal scutes, giving it a very smooth-skinned appearance when seen from a distance.

Unlike crocodiles, which have their nostrils on the top of their upper jaw, Champsosaurus had its nostrils on the front tip of its upper jaw. Perhaps they would use their long nose like a snorkel, sticking just the tip out of the water’s surface in order to stay as concealed as possible.

Champsosaurus had a pair of long thin gharial-like jaws lined with tiny conical teeth. Because of its close affinity towards lizards than to crocodiles, it is highly likely that Champsosaurus had lips and a fully enclosed mouth. But that’s just speculation based upon phylogenic relationships to other reptiles. In terms of hard physical evidence, the teeth themselves are quite small, and are inset from the edge of the jawline rather than standing on the rim of the jaw like a crocodile. This suggests that Champsosaurus had lips covering its teeth like a lizard, unlike crocodiles which don’t have lips.

Compared with crocodilians, the eye sockets of choristoderans are positioned much further forwards on the skull, located halfway or two-thirds of the way back from the tip of the snout. This provides more space for jaw muscles, and the temporal fenestrae (the holes in the back of the skull that accommodate the jaw muscles) were very large in proportion with skull size. Champsosaurus, in particular, had very large temporal fenestrae, which indicates that it had strong jaw muscles and could quickly snap its mouth shut within a fraction of a second – an important adaptation if your diet consists primarily of small fish.

Unlike lizards, Champsosaurus might not have had external ears. Analysis of its skull structure shows that Champsosaurus had internal ears, similar to turtles. This is an important adaptation if you are spending much of your life in the water. Therefore, you would not have seen a pair of ear holes on a Champsosaurus head. Instead, there likely just would have been a slight depression (or maybe not even that) on the side of the head marking where the tympanum (the part of the ear that vibrates in order to make a sound) would have been.

If you spend much of your life in the water, walking really isn’t an issue. Therefore, the limbs of choristoderans are not well-developed. In fact, the more “advanced” the species, the weaker its limb bones appear to be. Champsosaurus is no exception to this – its legs are downright puny in comparison with its body. The bones that make up the arms and legs are short and stumpy, and the hands and feet are small, although the feet are noticeably bigger than the hands. The fingers and toes are thin and end with very tiny claws. This was an animal that would have had a hard time pushing itself onto land. However, there is some evidence that females had more robustly-built limbs than the males due to the need to haul themselves onto land in order to lay their eggs.

The tail of Champsosaurus was flattened, and looked more like that of a crocodile or even a mosasaur than to a lizard. Even so, this animal was definitely not a power-swimmer. If it was, then one would expect the tail to be both longer and broader. Instead, the tail seems to be peculiarly under-developed. Keep in mind, though, that this was likely not an animal that was actively chasing after its prey. If all it was doing was hunkering down on the bottom of a lake or river and waiting motionless for fish to carelessly swim by, then it doesn’t need a well-built tail that’s designed for plowing through the water.

Skeleton of Champsosaurus laramiensis. From “The Osteology of Champsosaurus”, by Barnum Brown (1905). Memoirs of the American Museum of Natural History, volume 9, part 1. Public domain image. http://commons.wikimedia.org/wiki/File:Large_williston_champsosaurus.jpg.

Below is a drawing made of Champsosaurus laramiensis drifting about in a murky pond or stream somewhere in Montana during the late Cretaceous Period. This five-foot-long piscivore would have shared this environment with alligators, crocodiles, turtles, large freshwater fish like gars, sturgeons, and bowfins, and of course dinosaurs like Triceratops and Tyrannosaurus. The drawing was made with No.2 pencil on printer paper.

Anyways, keep your pencils sharp.

Haplocanthosaurus: An Enigmatic Sauropod from the Late Jurassic Period


The sauropods are the definitive image of the dinosaur. Almost always, whenever one hears the word “dinosaur”, the image of the long-necked long-tailed four-legged behemoth is what immediately springs to mind. The sauropods were the dominant land herbivores during the Jurassic Period of the Mesozoic Era, and some of our best specimens come from western North America.

In the Rocky Mountains, in the states of Utah, Wyoming, and Colorado lies a massive swath of Jurassic-age rock known as the Morrison Formation. Here are found fossils of some of the most well-known and iconic dinosaur species, names that everyone knows, like Allosaurus, Ceratosaurus, Apatosaurus, Brachiosaurus, Stegosaurus, and Diplodocus. The Morrison Formation was home to a myriad of different species, and not just dinosaurs either. Other prehistoric creatures that have been found in this rock layer include pterosaurs, crocodiles, turtles, lizards, frogs, fish, mammals, and even insects.

While there are a few dinosaur names that stick in people’s memories, the Morrison Formation was home to many dinosaur species. One of them, which is largely unknown by the general public, was a sauropod called Haplocanthosaurus. Part of the reason why this animal doesn’t have the same caché to its name as other Jurassic giants is because it is known from only partial remains, its fossils are extremely rare, and because it is found in the oldest layers of the Morrison Formation, far below the fossil-rich layers of the middle and late strata that have yielded thousands of finds. This article will be an overview of this mysterious and curious, but not quite forgotten, sauropod of the Late Jurassic.


Discovery, Localities, and Dating

In the very early 20th Century, the remains of a sauropod dinosaur were found about eight miles north of Cañon City, Colorado, and they were discovered and excavated by one Mr. W. H. Utterback. In early 1903, John Bell Hatcher gave these bones the identification of Haplocanthus priscus, “the ancient simple spine” (1).

However, Hatcher soon learned that the name was already used for a prehistoric fish, and so later that year, he re-classified the dinosaur as Haplocanthosaurus, “simple-spined lizard”:

“Dr. C. R. Eastman has very courteously called my attention to the fact that the generic name Haplocanthus recently proposed by me for a new Sauropod dinosaur from the Jurassic deposits near Canyon City, Colorado, is essentially preoccupied, Agassiz having employed the name Haplocanthus for a genus of fishes. I would therefore propose the name Haplocanthosaurus for this genus of dinosaurs with simple median spines on the anterior dorsals and posterior cervicals” (2).

Later that same year, Hatcher published a lengthy and detailed description of all of the bones assigned to this new genus (3).

In fact, Hatcher was mistaken – the name Haplocanthus wasn’t already occupied after all. According to the rules of the ICZN, the original name would have been the correct one to use, except that nobody had called this creature by that name since its discovery. A proposal was submitted in 1989 to have Haplocanthosaurus as the accepted name of this creature due to its common use and the fact that Haplocanthus was not acknowledged by the paleontological community. The request was approved in 1991, and Haplocanthosaurus became the definite name of this dinosaur genus (4).

In 1954, the Cleveland Museum of Natural History really wanted a large grand dinosaur skeleton to put on display, just like the ones that were on display at the American Museum of Natural History in New York City and the Carnegie Museum in Pittsburgh. So an expedition was sent out west to bring back an attention-grabbing huge dinosaur skeleton. The expedition was led, surprisingly enough, by a college undergraduate student named Edwin Delfs (5).

Their first destination was Dinosaur National Monument, located near the Utah-Colorado border, and they hunted for fossils around that area. Unfortunately, they didn’t find anything. However, the team received a tip from some geology students from Louisiana State University that they ought to check out a site in Garden Park, located near Cañon City, Colorado. (6).

Delfs and his teammates relocated to the suggested location, and on the eastern bank of Four Mile Creek, they hit paydirt. Here were the grandiose fossils that the Cleveland Museum was looking for. However, they couldn’t dig anything up yet. The United States had entered the Atomic Age, and due to the Red Scare of the 1950s, the country was manufacturing hundreds of atomic bombs every year. In order to fuel this doomsday machine, the military needed massive amounts of uranium. Many of the fossils that had been discovered out west during the post-WWII years had been discovered accidentally by people who were prospecting for uranium deposits. Due to all of the uranium deposits in the area, Edwin Delfs first had to file a mining claim on the site before he could dig up any fossils (7).

Over the course of three digging seasons, Delfs and his team chipped away at the stone. Part of the reason why it took so long was due to the extremely hard consistency of the rock that the bones were found in. Another reason was that sudden flash floods would completely flood the excavation site, and unfortunately some of the bones were washed away before they could be saved and prepared. After three years of on-off excavations, the team uncovered a large number of vertebrae and parts of the hip. The specimen, which was substantially bigger than Haplocanthosaurus priscus, was named Haplocanthosaurus delfsi by Dr. Jack McIntosh (who is widely regarded as the greatest sauropod expert EVER) and Dr. Michael Williams who served as the curator of vertebrate paleontology at the Cleveland Museum of Natural History. The jacketed bones were brought back to the Cleveland Museum to be prepared. The skeleton was put on display, and it remains one of the main attractions at the Cleveland Museum of Natural History, where it is affectionately known by the nickname “Happy” (8).

There are currently two species of Haplocanthosaurus known to science: H. priscus and H. delfsi. Both of them are known from comparatively few remains in relation to other late Jurassic sauropods. No complete skeleton has ever been found, and there are numerous bones missing from all known specimens, including the skull; no Haplocanthosaurus skull has ever been found, which makes it difficult to precisely place this species within the dinosaur family tree. So far, we have large chunks of the neck and backbones, a shoulder blade, a few vertebrae from the base of the tail, the hip bones, a few leg bones, and that’s it. Most fossils of this animal have been found in Colorado, but one specimen was found in Montana and was nicknamed “Big Monty”. However, this specimen was found on private property, and it is in the hands of a professional fossil collector and dealer (9).

Fossils of both species of Haplocanthosaurus are found in the early and middle levels of the Morrison Formation, although it is rare within both of those levels. It is completely absent from the late Morrison. It is possible that Haplocanthosaurus lived during the latest part of the Middle Jurassic and therefore straddled the boundary between the Middle and Late divisions. However, there are so few places within North America where Middle Jurassic rocks are exposed, and the number of fossils from those rocks has been aggravatingly miniscule. So, the question of whether or not Haplocanthosaurus was a Middle Jurassic leftover that survived into the earliest parts of the Late Jurassic cannot be answered yet (10).



Haplocanthosaurus is distinctive for vertebrae that have only a single dorsal neural spine as opposed to the double-pronged V-shaped dorsal neural spines found in the diplodocid sauropods like Apatosaurus and Diplodocus. It is this anatomical feature that earned it its name “simple-spined lizard”. The neck vertebrae of Haplocanthosaurus have proportionally small centrum disks, high neural arches, a tall dorsal neural spine, and transverse spines that stick out directly sideways. Haplocanthosaurus is also noted for having femur bones that are substantially longer than the shin bones. This hints that Haplocanthosaurus was a very slow-moving animal (11).

Size measurements are difficult to pin down, because paleontologists currently recognize two species of Haplocanthosautrus: H. delfsi and H. priscus. It appears that Haplocanthosaurus priscus measured only 50 feet long, making it the smallest sauropod yet found in North America, while Haplocanthosaurus delfsi measured 70 feet long. This distinction was not known until 1988. John Foster states that H. priscus likely weighed around 23,000 pounds (10,500 kilograms) while H. delfsi weighed 46,200 pounds (21,000 kilograms). The aforementioned size measurements mean that Haplocanthosaurus priscus was one of the smallest – if not the smallest – sauropod found within the Morrison Formation (12).



Haplocanthosaurus is a bit of an oddball as far as sauropods go because paleontologists haven’t quite made up their minds as to how to classify it. Because Haplocanthosaurus is known only from partial skeletons, deciding where it fits within the sauropod cladogram has proved problematic and aggravating, and paleontologists have repeatedly shuffled this genus around according to their own perceptions.

Due to the shape of its vertebrae, which were unlike those of more advanced sauropods, John Bell Hatcher surmised that Haplocanthosaurus must be a quite primitive. In his initial research paper, he described Haplocanthosaurus as most closely resembling Morosaurus, a name that is now recognized as a junior synonym of Camarasaurus. Since we now classify Camarasaurus as a member of the sauropod group Macronaria, a group which contains species known for having boxy heads and large nostrils, it can be inferred that Hatcher would have placed Haplocanthosaurus in that group as well (13).

Except that Haplocanthosaurus wasn’t included in Macronaria alongside Camarasaurus and Brachiosaurus. It was, instead, included in the family Cetiosauridae. The cetiosaurs were a group of sauropods that are associated with the Middle Jurassic, especially in England, India, and China. One reason why Haplocanthosaurus’ designation as a cetiosaur stuck around for so long was because of the shape and size of the leg bones. Cetiosaurs are characteristic for having femurs that are noticeably longer than their fibulae and tibiae. However, some members of other sauropod groups also have unusually long femurs, so this anatomical feature is not 100% diagnostic towards cetiosaurs (14).

From its discovery until the middle 1990s, the established convention was that Haplocanthosaurus was a cetiosaurid. And then, things began to change. During the middle 1990s, paleontologists began to take a new look at sauropod phylogeny, and many felt that Haplocanthosaurus had been misplaced on the sauropod tree. In 1998, Jeffrey Wilson and Paul Sereno proposed that Haplocanthosaurus might indeed be a primitive member of Macronaria, which is closer to what John B. Hatcher was hinting at in 1903. In 1999, Jose Bonaparte proposed that Haplocanthosaurus was unique enough to warrant a family of its own, which he named Haplocanthosauridae, but this idea was not accepted by the majority of paleontologists. In the early 2000s, it was suspected that Haplocanthosaurus might actually be a very primitive member of the super family Diplodocoidea. A survey conducted in 2005 by Mike Taylor and Darren Naish failed to definitely establish where this genus ought to be placed. John Foster, the author of Jurassic West, postulated in his 2007 book that Haplocanthosaurus was either a cetiosaur or a primitive macronarian. As the 2000s transitioned to the 2010s, the idea that Haplocanthosaurus was likely a primitive diplodocoidean began to gain acceptance within the paleontological community, and this is what most paleontologists now consider Haplocanthosaurus to be (15).

Because Haplocanthosaurus possesses anatomical features found in both sauropod families, it’s possible that it is a transitional species, a “missing link”, between the cetiosaurs of the middle Jurassic and the diplodocids of the late Jurassic. However, proving such a statement is problematic because of the rarity of finds attributed to this genus. Haplocanthosaurus is known from several partial skeletons, but no skull has ever been found. That’s too bad, because a complete skull would probably settle the argument of where this genus fits on the sauropod tree.

Below is a drawing that I made of Haplocanthosaurus. Because no skull has ever been found, I decided to make a sort of half-cetiosaur half-diplodocid design. The short keratinous scutes that run along the middle of its spine are a reference to such spines (longer ones at that) being found in association with diplodocid sauropods; if this was a primitive member of that family, I’m guessing that such spines would be shorter, if it possessed any at all. The tail is somewhat shorter than what you might expect, more in keeping with a cetiosaurid than a diplodocid. The drawing was made on printer paper with a No. 2 pencil.

Haplocanthosaurus delfsi. © Jason R. Abdale. June 21, 2020.



Due to the scarcity of remains, theories about Haplocanthosaurus’ appearance and phylogenic relationship to other sauropods are largely conjectural. Museum mounts depicting Haplocanthosaurus, such as the one in Cleveland, are composites of known finds and educated guesswork. In terms of cladistics, the in-vogue assessment is that Haplocanthosaurus is a very archaic member of the super family Diplodocoidea. However, this might change in the future depending on any new finds that are uncovered. All that we can hope for is that we keep looking, and hopefully we’ll be able to uncover some more specimens of this mysterious and intriguing North American dinosaur in the years to come.


Source Citations

  1. John Bell Hatcher (February 21, 1903). “A New Sauropod Dinosaur from the Jurassic of Colorado”. Proceedings of the Biological Society of Washington, 16 (1): 1-2).
  2. John Bell Hatcher (1903). “A new name for the dinosaur Haplocanthus Hatcher”. Proceedings of the Biological Society of Washington, 16 (1): 100).
  3. John Bell Hatcher (1903). “Osteology of Haplocanthosaurus, with description of a new species, and remarks on the probable habits of the Sauropoda and the age and origin of the Atlantosaurus beds. Memoirs of the Carnegie Museum, 2: 1–72).
  4. John R. Foster and Mathew J. Wedel (2014). “Haplocanthosaurus (Saurischia: Sauropoda) from the lower Morrison Formation (Upper Jurassic) near Snowmass, Colorado”. Volumina Jurassica, 12 (2): 197).
  5. “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017”.
  6. “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017”.
  7. “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017”.
  8. “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017”.
  9. “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017”; “Is Nate Murphy Holding a Dinosaur for Ransom?”.
  10. John Foster, Jurassic West: The Dinosaurs of the Morrison Formation and their World. Indianapolis: Indiana University Press, 2007. Page 200.
  11. John Bell Hatcher (February 21, 1903). “A New Sauropod Dinosaur from the Jurassic of Colorado”. Proceedings of the Biological Society of Washington, 16 (1): 1-2; John Foster, Jurassic West: The Dinosaurs of the Morrison Formation and their World. Indianapolis: Indiana University Press, 2007. Page 200; “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017”.
  12. John Foster, Jurassic West: The Dinosaurs of the Morrison Formation and their World. Indianapolis: Indiana University Press, 2007. Pages 200-201.
  13. John Bell Hatcher (February 21, 1903). “A New Sauropod Dinosaur from the Jurassic of Colorado”. Proceedings of the Biological Society of Washington, 16 (1): 2.
  14. David Lambert, The Dinosaur Data Book: Facts and Fictions about the World’s Largest Creatures. New York: Avon Books, 1990. Page 65; Don Lessem and Donald F. Glut, The Dinosaur Society Dinosaur Encyclopedia. New York: Random House, Inc., 1993. Page 208; Gregory S. Paul, The Princeton Field Guide to Dinosaurs, 1st Edition. Princeton: Princeton University Press, 2010. Pages 173-177.
  15. Jeffrey A. Wilson and Paul C. Sereno (June 15, 1998). “Early Evolution and Higher-Level Phylogeny of Sauropod Dinosaurs”. Memoir (Society of Vertebrate Paleontology), 5: 1-68; Jose F. Bonaparte (1999). “An armoured sauropod from the Aptian of northern Patagonia, Argentina”. In Proceedings of the Second Gondwanan Dinosaur Symposium, National Science Museum Monographs #15. Y. Tomida, T. H. Rich, and P. Vickers-Rich, eds. Tokyo. Pages 1-12; Mike P. Taylor and Darren Naish (2005). “The phylogenetic taxonomy of Diplodocoidea (Dinosauria: Sauropoda)”. PaleoBios, 25 (2): 1–7; John Foster, Jurassic West: The Dinosaurs of the Morrison Formation and their World. Indianapolis: Indiana University Press, 2007. Page 188; John A. Whitlock (April 2011). “A phylogenetic analysis of Diplodocoidea (Saurischia: Sauropoda)”. Zoological Journal of the Linnean Society, 161 (4): 872–915; Emanuel Tschopp, Octávio Mateus, and Roger B. J. Benson (2015). “A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda)”. PeerJ. 2015; 3: e857; “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017”.



Bonaparte Jose F. (1999). “An armoured sauropod from the Aptian of northern Patagonia, Argentina”. In Proceedings of the Second Gondwanan Dinosaur Symposium, National Science Museum Monographs #15. Y. Tomida, T. H. Rich, and P. Vickers-Rich, eds. Tokyo: 1-12.

Foster, John. Jurassic West: The Dinosaurs of the Morrison Formation and their World. Indianapolis: Indiana University Press, 2007.

John R. Foster and Mathew J. Wedel (2014). “Haplocanthosaurus (Saurischia: Sauropoda) from the lower Morrison

Formation (Upper Jurassic) near Snowmass, Colorado”. Volumina Jurassica, 12 (2): 197–210. https://sauroposeidon.files.wordpress.com/2010/04/foster-and-wedel-2014-haplocanthosaurus-from-snowmass-colorado.pdf.

Hatcher, John Bell (February 21, 1903). “A New Sauropod Dinosaur from the Jurassic of Colorado”. Proceedings of the Biological Society of Washington, 16 (1): 1-2. https://www.biodiversitylibrary.org/page/2345230#page/118/mode/1up.

Hatcher, John Bell (February 21, 1903). “A new name for the dinosaur Haplocanthus Hatcher”. Proceedings of the Biological Society of Washington, 16: 100. https://www.biodiversitylibrary.org/page/2345230#page/118/mode/1up.

Lambert, David. The Dinosaur Data Book: Facts and Fictions about the World’s Largest Creatures. New York: Avon Books, 1990.

Lessem Don; Glut, Donald F. The Dinosaur Society Dinosaur Encyclopedia. New York: Random House, Inc., 1993.

Paul, Gregory S. The Princeton Field Guide to Dinosaurs, 1st Edition. Princeton: Princeton University Press, 2010.

Taylor Mike P.; Naish, Darren (2005). “The phylogenetic taxonomy of Diplodocoidea (Dinosauria: Sauropoda)”. PaleoBios, 25 (2): 1–7

Tschopp, Emanuel; Mateus, Octávio; Benson, Roger B. J. (2015). “A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda)”. PeerJ. 2015; 3: e857. Published online on April 7, 2015. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4393826/.

Whitlock, John A. (April 2011). “A phylogenetic analysis of Diplodocoidea (Saurischia: Sauropoda)”. Zoological Journal of the Linnean Society, 161 (4): 872–915. Published online on January 12, 2011. https://academic.oup.com/zoolinnean/article/161/4/872/2732063

Wilson Jeffrey A.; Sereno Paul C. (June 15, 1998). “Early Evolution and Higher-Level Phylogeny of Sauropod Dinosaurs”. Memoir (Society of Vertebrate Paleontology), 5: 1-68.

Inverse. “Is Nate Murphy Holding a Dinosaur for Ransom?”, by Jacqueline Ronson (July 5, 2016). https://www.inverse.com/article/17806-sauropod-dinosaur-discovery-montana-fossil-hunter-paleontology-nate-murphy.

YouTube. ExtermCentral. “Haplocanthosaurus: The Ghost of the Morrison Formation by Dr. Cary Woodruff CMNH Dinofest 2017” (November 12, 2017). https://www.youtube.com/watch?v=-NWL7pjrPbI.


The middle to late 19th Century can arguably be seen as the glory days of paleontology. While this time frame is often associated with the discovery of dinosaurs and the so-called “Bone Wars” of the American West, discoveries were also being made elsewhere during this time and concerning the remains of prehistoric life other than those creatures that inhabit every child’s fantasies.

Europeans had known about the fossilized remains of prehistoric marine life ever since the Middle Ages. In the superstitious societies of those times, shells of prehistoric mollusks were often believed to be the nails and horns of devils. During the late 18th Century, grander discoveries were made, notably by the English paleontologist Mary Anning. Due to the impressive finds made by her and others, creatures like ichthyosaurs, plesiosaurs, and mosasaurs made their entrance into our collective knowledge of life.

During the middle 1800s, some isolated teeth were discovered in northern France. In 1873, these teeth were ascribed the name Liopleurodon, meaning “smooth-sided tooth” by the French paleontologist and biologist Henri Émile Sauvage. It was evident that the teeth belonged to a large prehistoric marine reptile, and it was established that this creature belonged to a group known as the pliosaurs, which had been named by Sir Richard Owen in the 1840s. The pliosaurs were close relatives of their more famous long-necked plesiosaur cousins; in fact, pliosaurs are sometimes referred to as “short-necked plesiosaurs”. The pliosaurs had the same general body plan as their plesiosaur relatives – a rounded stocky body with four large flippers and a short tail – but they had short muscular necks and long crocodile-like heads which were very large in proportion with their bodies. The pliosaurs seem to have emerged during the early Jurassic Period, and quickly rose to be apex predators of their environment. Some species, such as the eponymous Pliosaurus and its cousin Kronosaurus grew to be some of the largest marine reptiles in Earth’s history, with their size commonly stated to be 40 feet long, just as big as Tyrannosaurus rex.

The remains of Liopleurodon have been found in Britain, France, and Germany within rocks dated to the middle Jurassic/late Jurassic boundary, approximately 165-155 million years ago. Phylogenic analysis suggests that it was an advanced member of the pliosaur family. However, it was only half the size of its gargantuan relatives. Only partial remains of this animal have been discovered so far, so it is difficult to gauge an accurate size. However, the most common size estimates for Liopleurodon are between 20 to 25 feet in length. Even though it wasn’t as big as Pliosaurus or Kronosaurus, Liopleurodon was likely the top predator in the shallow sea that once covered Europe during the Jurassic Period.

Liopleurodon first came to my attention in 1994 when it was featured in issue #85 of Dinosaurs! magazine. In the article, it was mistakenly stated that it grew to be 39 feet (12 meters) long, a much larger size than the one it was likely in life. It was also portrayed, remarkably, as being mostly toothless except for a crescent of curved fangs extending from the front of both jaws.

Liopleurodon afterwards came to mass public attention in 1999 when it was featured in Episode 3 of the BBC series Walking With Dinosaurs. In this TV show, the creature bears only a general resemblance to the real animal. Firstly, there was a drastic difference in size. As said earlier, many paleontologists think that Liopleurodon had a maximum size of 25 feet. However, in Walking With Dinosaurs, Liopleurodon was portrayed as being three times larger, measuring 80 feet long, a truly gargantuan size indeed! This inflated size estimate was based upon a single fragmentary specimen uncovered in Mexico which was attributed to Liopleurodon and was believed to represent a gigantic individual. Although the evidence was flimsy, the producers took this as a cue and exaggerated Liopleurodon’s size to absurd proportions, claiming that it was the largest marine reptile that ever lived – it wasn’t. Secondly, the head was the wrong shape, with it being given a much more curvaceous high-arched skull. In reality, the skull was much lower and flatter. Thirdly, the body proportions were incorrect. It was stated in the episode that Liopleurodon’s head measured one-fourth the total length of its body. However, an article from 2003 stated that it was likely that the head measured one-fifth the total length of its body. This would have made its head seem somewhat smaller in relation to its body.

A reconstructed Liopleurodon skeleton can be seen in the Museum of Paleontology in Tübingen, Germany – you can see a photo of it here. Granted, much of the skeleton is fictitious, since only partial remains of Liopleurodon have been found in Europe, so the blank spaces were filled in with reconstructions based upon what we know about pliosaur anatomy. The first thing that one is struck by is that it is obviously much, much smaller than the size given in Walking With Dinosaurs. The skull is also much flatter than you would expect. This might be due to compression caused by the fossilization process rather than being an accurate portrayal of its natural appearance. However, there are other pliosaur species that have flat crocodilian-like skulls, so I’ll give it the benefit of the doubt. The front teeth in both jaws are enormous, while the majority of teeth that line its mouth were only one-half or one-third the size of the front teeth, and most of them are missing. This is probably the reason why Liopleurodon was portrayed as having only front teeth in a largely toothless mouth in the Dinosaurs! article. The front end of the lower jaw is noticeably spoon or scoop-shaped – it is pronounced in relation to the rest of the dentary bone, and it has an obvious upward swoop. Like the 2003 article states, the head isn’t as large in proportion with the rest of the body as the BBC series showed. The neck is longer, and it has a much more pot-bellied barrel chest. All in all, this looks very little like its representation in Walking With Dinosaurs. Given the character’s well-known imagery from that show, you might be forgiven in thinking that the specimen on display in the museum was actually a completely different species.

Finally comes the issue of color. Ever since its appearance on Walking With Dinosaurs, reconstructions of Liopleurodon, either two-dimensional images or rendered into three-dimensional sculptures and toys, have portrayed it with a piebald black-and-white color pattern. While the repeated use of this color scheme may seem to be becoming over-used to the point of being trite, there may be scientific foundation to it, since it was claimed in a scientific study that prehistoric marine reptiles were probably darkly-colored in order to absorb as much heat as possible. Furthermore, this color pattern has become widely recognizable as the most identifiable and therefore definitive Liopleurodon appearance, and this motif is unlikely to go away anytime soon.

Seeing this reconstructed skeleton left an impression on me, and I decided to make a series of illustrations of what Liopleurodon would have looked like in real life. In contrast to my usual style, which is highly detailed and would take me weeks or even months to finish, I decided to knock out a few quick black-and-white line drawings made with an ordinary black ballpoint pen.

First is a basic line drawing showing how Liopleurodon would look as it swam through the Jurassic ocean.

Second is another line drawing showing the iconic Walking With Dinosaurs color pattern, rendered to look like something that you’d see in a coloring book.

Finally is a colorized portrayal showing the classic black-and-white piebald color pattern.

I realize that these pictures may not be what you’d expect, especially given our engrained perceptions of what we think Liopleurodon ought to look like based upon its appearance in WWD, but holy heck, look at the size of those front choppers!!! It looks like something out of a nightmarish Wayne Barlowe painting! I hope you enjoy these pictures. Please like and leave any comments below.

Megalneusaurus, Before and After

Back in 2013, I posted a picture of the 25 foot long pliosaur known as Megalneusaurus, which swam in a shallow sea that once covered the central part of North America during the middle and late Jurassic Period. The illustration that I put up was based heavily upon a skeletal drawing of Liopleurodon, it had hardly any detail, and the skull was shockingly shrink-wrapped. Not my best work.

I’m happy to say that I have recently done a revised drawing of this 25-foot long marine reptile, and I think that it’s a substantial improvement over the earlier illustration. Here is the “new and improved” version…

This drawing was made in 1/20 scale with No. 2 and No. 3 pencils on roll paper, with some touch-up tweaking on my computer. From the tip of its nose to the tip of its tail, this animal measures 15 inches long, which would make it 25 feet long in real life. As for the fish swimming around it for protection, they’re just generic fish, I suppose. I tried to find images of fish fossils from the Sundance Sea, but I couldn’t find anything worthwhile.

Hope you enjoy it. Please like and comment.



Ophthalmosaurus was a 20 foot long ichthyosaur which swam in the oceans around Europe during the middle and late Jurassic Period. It is named after its distinctive large eyes.

The coloration in the illustration that you see below is based upon the Spotted Dolphin (Stenella frontalis). This drawing was made with No.2 pencil, No.3 pencil, and marker for the eye.

OphthalmosaurusOphthalmosaurus. © Jason R. Abdale. October 4, 2014. 


UPDATE: Below is a revised version which I made, which has more accurate body proportions. This drawing was made with No.2 pencil, No.3 pencil, and Prismacolor colored pencils.

Ophthalmosaurus. © Jason R. Abdale. August 14, 2020.

Keep your pencils, and your scientific information, sharp.