Coelurus is one of my favorite theropod dinosaurs, and has been since I was young. It’s not as well-known as other Jurassic theropods like Allosaurus, Ceratosaurus, and Ornitholestes, partly because it is only known from fragmentary evidence. Yet I’m always intrigued by animals that we only have fragments of because that gives my imagination room to play. This dinosaur had pretty high popularity during the 1980s and early 1990s – it was featured in nearly every dinosaur book during that time, right alongside the more famous names that everybody knows. Since then, Coelurus has largely dropped off of the radar and has become a rather obscure species.
Coelurus had a much thinner build than its Morrison Formation coelurosaurid counterpart Ornitholestes, and it was also bigger. Ornitholestes measured 6 feet long and scarcely 2 feet tall, while Coelurus measured 8 feet long and 3 feet tall. Note the unusually long metatarsal bones. With its long lanky legs, Coelurus was probably a very good runner. I imagine it having the same ecological niche as a Secretary Bird today on the African Savannah.
I have made four previous drawings of this animal, but all of them were inaccurate in one way or another, or I was simply not satisfied with the way that the end product looked. Therefore, I decided that I needed to re-do my Coelurus yet again. This is my fifth iteration of this animal’s design, and this time I think I’ve more-or-less got it right. Made on printer paper with No. 2 pencil. The colorized version was made with Crayola and Prismacolor colored pencils.
The final image that you see below is a size comparison showing Coelurus fragilis (8 feet long) and its counterpart Ornitholestes hermanni (6 feet long) in order to give you a greater appreciation of their anatomical differences.
Keep your pencils sharp, everyone.
I feel the coming of the flowery Spring,
Wakening tree and vine;
A bowl capacious quickly bring
And mix the honeyed wine.
Weave for my throat a garland of fresh dill,
And crown my head with flowers,
And o’er my breast sweet perfumes spill
In aromatic showers.
– Alcaeus of Mytilene
April 23 was the date of the Vinalia Priora, literally “the Festival of Wine from Last Year”, which was dedicated to the gods Jupiter and Venus. This was the ceremonial first-tasting of the wine that had been bottled and casked during the previous autumn and which had been fermenting over the winter. An offering of the first wine to be opened was made to the god Jupiter. Afterwards, the rest of the wine could be tasted.
“The Vinalia ‘Festival of the Wine,’ from vinum ‘wine’; this is a day sacred to Jupiter, not to Venus. This feast receives no slight attention in Latium; for in some places the vintages were started by the priests, on behalf of the state, as at Rome they are even now: for the special priest of Jupiter makes an official commencement of the vintage, and when he has given orders to gather the grapes, he sacrifices a lamb to Jupiter, and between the cutting out of the victim’s vitals and the offering of them to the god he himself first plucks a bunch of grapes. On the gates of Tusculum there is an inscription: The new wine shall not be carried into the city until the Vinalia has been proclaimed” (Marcus Terentius Varro, On the Latin Language, book 6, verse 16. Translated by Roland G. Kent. London: W. Heinemann, 1938. Page 189).
In addition to offering libations of wine to Jupiter, a similar ritual was dedicated to Venus. Venus was the patron goddess of prostitutes, for reasons that I think are self-evident. On this day, the “ladies of the evening” would gather at her temple, burn incense, and give offerings of myrtle, mint, rushes, and roses.
“The Vintage Festival”, painted by Lawrence Alma-Tadema (1871)
“You prostitutes, celebrate the divine power of Venus: Venus suits those who earn by your profession. Offer incense and pray for beauty and men’s favour, pray to be charming, and blessed with witty words, give the Mistress myrtle, and the mint she loves, and sheaves of rushes, wound in clustered roses. Now’s the time to crowd her temple near the Colline Gate, one that takes its name from a Sicilian hill: When Claudius took Arethusian Syracuse by force, and captured that hill of Eryx, too, in the war, Venus moved to Rome, according to the long-lived Sibyl’s prophecy, preferring to be worshipped in her children’s City. Why then, you ask, is the Vinalia Venus’ festival? And why does this day belong to Jupiter? There was a war to decide whether Turnus or Aeneas should be Latin Amata’s son-in-law: Turnus begged help from Etruscan Mezentius, a famous and proud fighter, mighty on horseback and mightier still on foot: Turnus and the Rutuli tried to win him to their side. The Tuscan leader replied to their suit: ‘My courage costs me not a little: witness my wounds, and my weapons that have often been dyed with blood. If you seek my help you must divide with me the next wine from your vats, no great prize. No delay is needed: yours is to give, mine to conquer. How Aeneas will wish you’d refused me!’ The Rutulians agreed. Mezentius donned his armour, and so did Aeneas, and addressed Jove: ‘The enemy’s pledged his vine-crop to the Tyrrhenian king: Jupiter, you shall have the wine from the Latin vines!’ The nobler prayer succeeded: huge Mezentius died, and struck the ground, heart filled with indignation. Autumn came, dyed with the trodden grapes: The wine, justly owed to Jupiter, was paid. So the day is called the Vinalia: Jupiter claims it, and loves to be present at his feast” (Ovid, Fasti, book 4, April 23)
- Marcus Terentius Varro, On the Latin Language, book 6, verse 16. Translated by Roland G. Kent. London: W. Heinemann, 1938.
- Ovid, Fasti, book 4, April 23. Translated by A. S. Kline, 2004. https://www.poetryintranslation.com/PITBR/Latin/OvidFastiBkFour.php.
- Alcaeus of Mytilene. “Spring”. In The Songs of Alcaeus, translated by James S. Easby-Smith. Washington: W. H. Lowdermilk & Co., 1901. Page 45.
This is Hallopus victor, a 3-foot long reptile that lived in the Morrison Formation of western North America during the late Jurassic Period approximately 150 million years ago. Hallopus belonged to a group of reptiles called the “sphenosuchians” a group that was closely related to crocodiles. Another example of a Jurassic sphenosuchian is the 5-foot-long Macelognathus, which you can read about here.
Hallopus is only known from fragmentary remains. However, we know that it had a thin build and it also had unusually long back legs. This suggests that Hallopus was a physically active predator that ran after its prey, and would have been capable of running on only their hind legs like a theropod dinosaur. Hallopus had a narrower pointier skull compared to its much larger relative Macelognathus, and would have looked similar in many respects to Terrestrisuchus, a 3-foot-long sphenosuchian from Europe. However, like Macelognathus, Hallopus had no teeth in the front end of its lower jaw; Terrestrisuchus, by contrast, had a full set of teeth. Thus suggests that Hallopus may have been an egg-eater.
Sphenosuchians like Hallopus, Macelognathus, and Terrestrisuchus have traditionally been depicted in paleo-art as being quadrupedal. However, many of the renditions of these animals walking quadrupedally look downright awkward. The back is shown as being strongly arched to the point where it looks as if its spine is being curved beyond its natural state, the joint between the cervical vertebrae and the dorsal vertebrae is cranked into a very uncomfortable position, and due to its long back legs, its rear end is so high up in the air that it almost looks as if its “presenting” to its mate.
Below is a drawing depicting Hallopus in the traditional quadrupedal manner. You can see some of the inherent problems in reconstructing an animal like this.
It’s more likely that these long-legged crocodile relatives were bipedal. As to how often they were bipedal, that’s a subject for debate. An “obligate biped” means that it was bipedal all or most of the time; moving on two legs was its default setting. A “facultative biped” means that it was usually quadrupedal, but it could rear up on its back legs if it wanted to. So, was Hallopus an obligate biped or a facultative biped? With its unusually long back legs, I am more than inclined to believe that Hallopus spent most of its time on two legs.
Below is a revised drawing showing Hallopus standing upright on two legs. This is probably the more accurate way of depicting this animal.
I hope that you found this interesting, and I also hope that it leads you to challenge the common traditional images that have dominated aspects of paleo-art for so long. Keep your pencils sharp, everyone.
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.
This is Macelognathus vagans. This animal lived in the Morrison Formation of western North America during the late Jurassic Period approximately 150 million years ago.
Macelognathus belongs to a group of animals called the “sphenosuchians”, which is a group that’s very closely related to crocodiles. They even possessed a double-row of crocodilian-like scutes running down the middle of their back. However, unlike crocodiles, sphenosuchians were 100% terrestrial animals, and likely occupied the same ecological niche that foxes and wildcats do today. Most sphenosuchians were small, measuring 3 feet long or less, but Macelognathus was unusually large, measuring 5 feet long (this size measurement is only an estimate, since a complete skeleton has never been found). The anatomy of sphenosuchians strongly suggests that they were physically active animals that were built for the chase. Many species possessed a long lithe body, short front legs and long back legs, and a long thin tail. Sphenosuchians were possibly “obligate bipeds”, meaning that they always walked around only on two legs, but they were almost certainly “facultative bipeds”, meaning that they could sometimes move on two legs if they wanted to.
Macelognathus is known from only fragmentary remains, including the front half of its lower jaw. What is most distinctive about this animal is that the front of its lower jaw was toothless, forming a flat palate. So far, we have not found an upper jaw, so we don’t know if the front of both the upper and lower jaws were toothless, but it seems highly probable. Based upon its jaw structure, it’s likely that Macelognathus was a creature that had a particular preference for eating eggs. The image that comes to mind of this animal, therefore, is a nest-raider, a scavenger, or an ambush predator. I liken it as a Jurassic analog of a large monitor lizard.
There is some evidence which suggests that Macelognathus and another sphenosuchian named Hallopus are in fact the same animal. However, since both Macelognathus and Hallopus are known from only fragmentary remains, a definite answer cannot be given until more remains of both species are discovered and can be compared.
The drawing below was made with No. 2 pencil on printer paper.
Disclaimer: Even though the back legs are noticeably longer than the front legs, it’s still possible that I made the back legs too short in this drawing.
Keep your pencils sharp, everyone.
Hello. Here are a pair of images showing Dryosaurus, a 10 foot long ornithopod from the Late Jurassic of North America, and possibly also Europe and Africa as well. The images were made on printer paper with No. 2 pencil, Crayola and Prismacolor color pencils, and quite a bit of touch-up on the computer after they were scanned.
Yes, I know that the pictures are dated to September 2019, but it’s only recently that I’ve gotten around to scanning them.
I wanted to evoke an image of a reptilian antelope or gazelle, because these animals likely occupied a similar ecological niche on the Late Jurassic savannah.
Keep your pencils sharp.
Ceratosaurus is an iconic dinosaur due to numerous physical attributes that distinguish it from other theropod species: the horn on the end of its nose, the massive teeth, the tiny hands with the four fingers, the wide tail, etc. However, the main focus of this article are its osteoderms – the bony bumps that were on its back. What were they, where exactly on the body were they, and what did they look like?
Despite its instantly recognizeable profile, Ceratosaurus fossils are surprisingly rare. Only a handful of skeletons have been found, and all of them are incomplete. Of these specimens the things which are especially unlikely to be preserved are its osteoderms. These small bony lumps (there’s really no other way to describe them) occured in a row running down the middle of its back, and it is one of this animal’s more distinctive features. It is one of only two theropod species (the other being Carnotaurus) which are known to have possessed body armor. Yet “armor” is hardly the word that I would use to describe this anatomical attribute, as we shall see later.
In order to make an accurate picture of Ceratosaurus, I needed to get as much information as I could about its osteoderms. So far, nobody has done a comprehensive study of Ceratosaurus osteoderm morphology – there’s a paleontology Master’s thesis that’s just begging to be picked up by someone. There wasn’t much information to go on because written descriptions of the osteoderms are rather scant. Only a few mounted specimens of Ceratosaurus include the osteoderms as part of the display, and I’m not aware of any museum having Ceratosaurus osteoderms housed in its collections departments.
Charles W. Gilmore says the following in his description of Ceratosaurus fossils:
“Several dermal ossifications were found with the type specimen of Ceratosaurus nasicornis, and some of these were so retained in the matrix as to indicate their exact position in relation to the internal skeleton of the living animal. Reference is made here to the row of elongate, irregularly shaped, bony ossicles present above the spinous processes of caudals (fig. 1, pl. 22) 4 to 10 inclusive, and above cervicals 4 and 5 (0, pls. 29 and 30). The position of these ossicles would appear to indicate a continuous row of dermal ossifications, extending along the median line of the back from the base of the skull well down on the tail, if not the greater part of its length…The ossifications above the tail are from 25 to 38 mm above the tops of the spinous processes of the vertebrae, evidently indicating the thickness of the skin and muscles between them and the tops of the spines. Those on the neck are much closer to the vertebrae, and in one instance appears to rest on the spine (figs. 1, 2, and 3, pl. 20). That there were other dermal ossifications is shown by the presence of a small skin plate found with the bones of this skeleton. It had been freed from the matrix when it came into my hands, so there is no evidence as to its probable position in the skin. It is a relatively small subquadrangular plate of bone 58 by 70 mm., with a comparatively smooth ventral and a roughened dorsal surface. The under surface is gently concave in the direction of its shortest diameter, with a low longitudinal swelling extending through the middle of its longest diameter. The roughening of the external surface is without definite pattern” (Charles W. Gilmore, Smithsonian Institution-United States National Museum, Bulletin 110 – “Osteology of the Carnivorous Dinosauria of the United States National Museum, with a Special Reference to the genera Antrodemus (Allosaurus) and Ceratosaurus”. Washington: Government Printing Office, 1920. Pages 113-114).
Unable to examine these osteoderms in person, I did the next best thing – I looked at as many pictures of Ceratosaurus osteoderms as I possibly could, and I made the following observations:
- There was only one row of osteoderms running along the middle of its back.
- The osteoderms are all fairly small.
- The osteoderms are irregularly shaped.
- From overhead, the osteoderms appear to be diamond or lozenge-shaped, elongated anteriorally-posteriorally.
- The osteoderms were smooth underneath, but they had a rugose texture on their upper surface.
- Some osteoderms seem to come to a point on their upper surface, while others come to a low ridge, and others don’t have any raised features at all. This might be due to the fossilization process.
The appearance of the osteoderms was somewhat perplexing to me. In numerous examples of paleo-art, these bony knobs were shown as pronounced features, more or less uniform in shape, often being exposed bone or bone covered with a thin scute. However, the physical evidence doesn’t look anything like the commonly-portrayed iconography. If the osteoderms themselves were used for display purposes (as they likely were, since the use of a single row of small pieces of bone as armor would only be minimally protective), then they would have been much larger, much more pronounced, more uniform in appearance, and would have had a more “finished” look to them in order to make them more visually apparent. As they are, these formless bony lumps would have made a poor sight, and they certainly would have been of little use as armor.
The rough texture of the osteoderm’s dorsal surface implies that they had a covering of keratin atop them. Due to the irregular shape of the osteoderms, it is also implied or inferred that the osteoderms themselves were not the visual focus, but rather, what was on top of the osteoderm was. It’s possible that each of these small osteoderms served as the anchor point for a large keratinous scute which extended upwards from the dorsal surface of the osteoderm, possibly for a considerable distance. The image that comes to mind is that of the spines which are seen running along the backs of some lizards like a crest, such as the iguana.
In 1990, a specimen of Diplodocus was discovered with skin impressions, and among these were a series of iguana-like keratinous spines running along the top of the animal’s vertebrae. It’s therefore possible that Ceratosaurus might have had a similar appearance.
With all of this being considered, I decided to revise my Ceratosaurus drawing that I had made in April 2012. In the original drawing, the animal has a single row of osteoderms that form a line of low semi-circular bumps, looking very much like crocodilian armored scutes. You can see that drawing below.
Now, I changed the animal’s appearance by extending the osteoderms with the addition of a keratinous scute, shaped like the spines of a lizard (although my impression was that they actually looked more like theropod teeth). I also took the time to touch up the drawing’s overall color and smoothness. You can see the updated drawing below.
When I decided to alter the shape of the osteoderms with the addition of the erect spines, I noticed two important changes to the animal’s overall appearance. Firstly, it made the animal taller. In real life, the addition of a few inches of height would have made the animal seem bigger and more imposing than it actually was. Secondly, it gave the animal a much more intimidating appearance, like a “razorback” wild boar. This might have been helpful in disputes over carcasses or competition for mates. It is unknown whether both male and female Ceratosaurus possessed this feature because so few fossils have been found that a sexual compare-and-contrast cannot yet be performed. However, it is almost certain that the males were ornamented in this way.
I hope that you found all of this interesting. Keep your pencils sharp.