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Caturus

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.

Hybodus, the iconic shark of the dinosaur age

Many people, usually un-informed talking heads that appear on populist nature documentaries who want to make claims that will grab your attention, will say that sharks have remained unchanged since the time of the dinosaurs. It’s wrong. The Mesozoic Era, the age of the dinosaurs, was a time of great transition for sharks. Sharks had existed on Earth for millions of years before the first dinosaurs appeared, ever since the Devonian Period when creatures like Cladoselache swam in the oceans around 370 million years ago. However, these were very primitive sharks that bore only a slight resemblance to most of the sharks that are found in the oceans today. The closest visual comparisons that we have for many prehistoric species are those that are found in very deep water, even though these sharks are still thoroughly modern in their genetics and evolutionary history. Sharks that are described as “modern” by biologists and paleontologists appeared towards the end of the Mesozoic Era during the late Cretaceous Period. Examples of prehistoric “modern sharks” are Cretoxyrhina and Squalicorax, both of which look like many shark species that are alive today.

During the Mesozoic Era, new shark forms emerged that could be described as transitional, a sort of in-between stage between the primitive sharks of the Paleozoic Era and the modern sharks of the very late Mesozoic. The most recognizable of these transitional species were a group of sharks called the “hybodonts”. Part of the reason why the hybodonts are regarded by many as THE shark group of the dinosaur age is because they lasted for such a long time. The hybodonts first emerged during the Carboniferous Period and they stuck around until the very end of the Cretaceous – that’s a LONG time! The hybodonts, therefore, existed throughout the entire duration of the Mesozoic Era. No wonder that they are considered the archetypal Mesozoic shark. Another reason for their status as the sharks that most people think of as dinosaur-age sharks is that they were widespread. Hybodont sharks existed all over the world during the Mesozoic, and they appeared to have existed in every aquatic niche: freshwater, brackish, and saltwater. Perhaps, like modern-day Bull Sharks, they had the ability to migrate in and out of water with different salinity levels without suffering adverse effects.

The most well-known of all of the hybodont sharks is its eponymous member Hybodus, a genus composed of several species which survived and thrived during the dinosaur age. It measured 6 feet long, and it occupied marine habitats around the world, although it is especially known from fossils found in Europe. Below is a drawing that I made of it based upon numerous fossils and scientific articles that I found. I noticed that the profile of the creature looked remarkably similar to a modern-day Blunt-Nosed Six-Gill Shark (Hexanchus griseus), with its rounded blunt nose and the characteristic humped back. Hybodus’ pectoral fins were surprisingly small and convex along the posterior edge, looking similar to the pectoral fins on numerous species of bottom-dwelling sharks. I get the impression that Hybodus was somewhat lethargic and spent much of its time cruising near the sea bottom, but that’s just my guess. The drawing was made with No. 2 pencil.

Keep your pencils sharp.

Liopleurodon

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.

Ophthalmosaurus

 

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.

Archaeopteryx

Archaeopteryx

In a previous post, I talked a little bit about the “raptor” dinosaurs and how they had feathers. Here is a drawing of Archaeopteryx, long reputed to be the earliest-known bird. It lived during the late Jurassic Period in what is now central Europe. I read somewhere that Archaeopteryx likely had black feathers, so it is portrayed has having dark feathers with white tips and a white belly. The only colored part is its eyelids, which are red – I put that in there just to give it some visual contrast.

I read today that the original color analysis of Archaeopteryx’s feathers was incorrect. It turns out that the wings were actually light colored with dark tips, not the other way around. Oh well. If you want to read the online National Geographic article, here it is:

http://news.nationalgeographic.com/news/2013/06/130614-dinosaur-xray-bird-color-feather-archaeopteryx/