de(i)nonychus

10. ANOMALOCARIS (~ 525 Ma) This one metre long invertebrate surely deserves to be included on the list, being one of the first complex oceanic predators to ever have existed. Anomalocaris stalked the Cambrian oceans, viewing the world with a deadly new evolutionary innovation - eyes. Complex eyes allowed this creature to storm its way to the top of the food chain, and with powerful appendages covered in spines it had no trouble devouring prey with tough carapaces. Whilst Anomalocaris is dwarfed by the other contenders on this list, it was still over 10 times larger than any other animal of its time.

9. KRONOSAURUS (125-99 Ma) Kronosaurus, a Cretaceous mosasaur, is named after the Greek titan, Cronus. Its name is well deserved as this ancient beast was a remarkably powerful being. Kronosaurus could reach up to 10 metres long and had a mouth full of sharp, conical teeth. Unlike most other mosasaurs its tail was relatively short, however, evidence shows that Kronosaurus has immensely powerful fins and a pectoral girdle making it an impressive swimmer and hunter.

8. HELICOPRION (290-250 Ma) Helicoprion has astounded scientists since its discovery over 100 years ago. It is iconic for its bizarre spiral of teeth, there are still debates on where exactly these teeth where on the shark with proposals stating they were inside the mouth, on the tip of the tail, the dorsal fin or hanging under the jaw. The most commonly accepted location of the teeth is inside the lower jaw enabling Helicoprion to cleanly slice its prey into pieces.

7. XIPHACTINUS (~110-70 Ma) Xiphactinus was an extraordinary fish that lived during the Cretaceous. It was an esteemed predator that could reach an incredible 6 metres in length and specimens are renowned for their stunning preservation. One such example was 4 metres long and found with another exceptionally well preserved fish just short of 2 metres inside it implying that this particular Xiphactinus individual died shortly after its last feast. Xiphactinus had immensely sharp, slim teeth and an unmistakable underbite which was a possible aid when snaring creatures from below.

6. TYLOSAURUS (86-75 Ma) Tylosaurus is considered a mosasaur and was a vivacious predator all be it smaller than its relative Mosasaurus. Tylosaurus could reach up to 15 metres in length and was one of the apex predators of its day. Fossilised stomach contents of Tylosaurus contain fish, sharks, turtles and other marine reptiles. Despite having an impressive set of teeth, the frontal areas of the jaws exhibit a large reduction in tooth size as well as a more heavily reinforced snout in comparison to other mosasaurs suggesting that Tylosaurus may have rammed into victims with immense force damaging prey internally.

5. MOSASAURUS (70-66 Ma) The mosasaurs ruled the Cretaceous oceans and Mosasaurus was no exception. It could reach up to 17 metres long, longer than most other mosasaurs. Mosasaurus had a strong jaw packed with numerous conical teeth, bite marks of which have been found in huge prehistoric turtles and ammonites suggesting that Mosasaurus was a formidable hunter capable of catching large prey. Mosasaurus was a profound swimmer with strong paddle-like limbs and a huge tail capable of rapidly accelerating the animal when required.

4. DUNKLEOSTEUS (382-358 Ma) Dunkleosteus terrorised the oceans around 370 million years ago and was part of a dynasty known as the placoderm fish (meaning armoured). Dunkleosteus could reach a whopping 6-10 metres in length and probably weighed over a ton. The skull was made up of huge, solid bony plates giving unrivalled protection allowing them to dominate the oceans. Placoderm fish were some of the first organisms to have a mobile jaw, as can be seen in Dunkleosteus’ impressive shearing plates which were used to slice cleanly through prey. Despite an revolutionary jaw, Dunkleosteus could not chew and several fossilised regurgitated remains of its meals have been found that the giant fish simply could not stomach.  

3. DAKOSAURUS (157-137 Ma) Dakosaurus was the largest of a group of marine reptiles that were distant relatives of crocodiles. Dakosaurus could reach up to 5 metres long and had a streamlined body with large paddle-like fins and a long muscular tail implying that is was a very efficient swimmer. The diet of Dakosaurus consisted mostly of fish. The teeth of Dakosaurus are lateromedially compressed and serrated which is a similar morphology to modern killer whales indicating that Dakosaurus was an apex predator of the Jurassic oceans. Skull fenestrae provides evidence that Dakosaurus had very large adductor muscles (which are responsible for the jaw closing) and so it was certainly capable of a forceful bite.

2. LIOPLEURODON (160-155 Ma) Liopleurodon stormed the Jurassic oceans, its huge 7 metre long frame effortlessly cruised through the water. The skull itself could reach a massive 1.5 metres long with a jaw that was packed with teeth up to 10cm long and was capable of an immense bone-crushing force. Liopleurodon was a remarkable hunter with the ability to swim with its nostrils open and so could use its powerful sense of smell to track prey from afar, much like sharks do. Liopleurodon most likely had good camouflage such as a lighter underside and a darker topside so it would blend in with the water to prey above and below.  

I actually never got around to uploading this guy here!

I drew a strawberry shortcake flavored Chasmosaurus, in a new style that I’ve been trying to cement down after accidentally creating this!

While complete skeletons are very rare, this fossil’s near perfect condition makes it even more remarkable.

Diagnostic anatomical reconstruction of Deinonychus antirrhopus, intended loosely for Wikipedia but also as an experimental piece to show pretty much exactly how I believe this animal looked in life.

This was largely inspired by an interesting Facebook discussion with paleoartist Julius Csotonyi about arm-folding in paravian dinosaurs. It occurred to me that people seldom reconstruct paravians, particularly dromaeosaurs, with their arms folded in a reasonable and accurate way. Julius made the fair point that these animals probably didn’t carry their arms out in front of the body, as is so often depicted (in skeletals and otherwise — it makes sense in skeletals, to adequately show the hand and arm anatomy), because such an awkward orientation would leave the hand and arm feathers open to damage and breakage. But they also can’t fold them tightly against the breast or back like birds do, because they lack the mobility to do so.

So how did Deinonychus normally carry its arms? Senter’s 2006 paper on forelimb function in Deinonychus and Bambiraptor shows that the humerus couldn’t rotate much past the horizontal with respect to the scapula. In addition, Sullivan et al. 2010 — winningly translated to layman coherency by Matt Martyniuk — shows that wrist mobility in many paravians is much less than you might expect, given their similarity to birds. The wrist of Deinonychus antirrhopus specifically would not have allowed it to bend its hands even 90° with respect to the arm!

Given these limitations, most of the flexion would have to occur at the elbow, but a fully flexed elbow would mean that the hands would be hanging below the body, not held sleek and secure alongside the body. The arm orientation in my illustration above is based on what I think is probably the perfect configuration for carrying the arms: a fully-flexed shoulder, a fully-flexed wrist, and a nearly fully-extended elbow. A few other people have drawn their dromaeosaurs with the same arm configuration, like Smnt2000 and Pilsator, so kudos to them.

V for Velociraptor!

6 meters tall, it could “stare a giraffe in the eye”. 16 meter wingspan, as large as an aeroplane. A pterosaur that is by far the largest creature ever known to fly. It’s estimated quetzalcoatlus could travel almost half of the circumference of the earth in a single flight, by gliding and exploiting thermals. Truly majestic.

Deinonychus antirrhopus

Artwork by Julio Lacerda / @paleoart

In the late 1960’s, the discovery of Deinonychus challenged the notion that dinosaurs were sluggish giants. This lightly built predator would have pinned down its prey with its sickle claws like today’s hawks.

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Deinonychus is the original dinosaur that was incorrectly named “velociraptor” in the Jurassic Park movies.

The Velociraptor is in reality not bigger than a turkey.

Deinonychus is much larger and more popular among artists and dinosaur-fans, alongside with the T-Rex.

It was quick and agile, probably lived in small packs, and some studies suggests that Deinonychus had the biggest brain (in relation to its body) of all theropods and therefore was very intelligent - they probably hunted their prey with a certain level of organization.

Drawing Deinonychus is very fun! But as we all know, finding any good references of dinosaurs is not easy.

So I’ll give you a brief and quick guide in what to keep in mind when drawing a deinonychus - with as realistic anatomy as possible.

Now, we can use an existing animal as a rough reference for the Deinonychus - BIRDS

Dinosaurs in general IS NOT REPTILES.

DINOSAURS= BIRDS.

The dinosaurs has two thing in their anatomy that you can only find in birds:

The Wish bone’s purpose is to make the arms being able to move like wings. And since dinosaurs where the ancestors of today’s birds, they all had an anatomy almost identical to birds as we know them today.

So, in order to learn ourselves how to draw a natural looking dinosaur, we have to stop seeing them as reptiles and start seeing them as bird-like creatures.

The Deinonychus probably had feathers, however, for now we will stick with the naked Jurassic Park-version in order to understand it’s anatomy. Please observe how the arms are held like a bird has it’s wings.

Here’s a easy example of how you connect the neck with the body. Remember that theropods like velociraptor and deinonychus had very slim and slender bodies. Not wide and rough like a t-rex or carnotaurus.

Deinonychus has four toes, one small, two medium and then of course the well known claw.

Even if some dinosaurs have legs like the right ecample, raptors like Deinonychus looks more like the one to the left.

Two simple steps in how you draw the head in profile. Notixe that the back of the head is actually the neck.

Another thing dinosaurs have in common with birds, is that they have “Eye Bones”.

The size of the “Eye-bones” determines the size of the eye-lob. So archeologists can actually see what size the eyes was on the species.

VERY COMMON MISTAKE

ALL land-living predators (and birds) have the eyes facing forwards, only herbivores have their eyes placed at the sides of the head.

And here’s some last sketches to show the dimensions of the Deinonychus head.

I will be using Scott Hartman’s skeletal as a reference. (The Greg S. Paul one you posted is a little outdated) Something to note is the skull is less robust and the hands are a bit bigger.

Another thing that’s important to note is that while the JP raptors were in fact based more on Deinonychus than Velociraptor (which was even smaller), they were still much bigger than the actual animal. 

Better candidates for JP sized raptors would be Utahraptor, Achillobator, and Dakotaraptor. All of which were discovered post-Jurassic Park (Utahraptor was actually described the same yeah the Jurassic Park movie was released).

Deinonychus doesn’t hold the record for most intelligent known dinosaur, that actually goes to Corvids (crows, ravens, etc.), but if we are talking non-Avian dinosaurs, our best bet would be Troodontids. That’s not to say that other “raptors” like Deinonychus weren’t intelligent in the dinosaur world too!

That leads to my other point; that dinosaurs are still reptiles. We just don’t think they are coldblooded anymore like lizards and crocodiles. In fact, birds are considered dinosaurs now (rather than simply decedents), and therefore considered reptiles as well since we now classify things differently than before. (Common ancestry rather than common traits.) A cool way to think about it is that the closest living relative to crocodilians are birds, rather than other reptiles like snakes and lizards.

Your reconstructions follow the skeletal pretty nicely (no hand pronation, yay!), but I noticed that you seem to shrinkwrap (a common mistake seen in reconstructing prehistoric animals). The fenestrae (holes in the skull) should not be visible on the animal, and the pubic bone should not be sticking out like that (that sort of construction is left over from when we thought dinosaurs were more lizard-like, iirc).

Here I just traced over Scott’s skeletal for a quick example of what I mean. You always want to add more flesh than the skeletal gives you. Make it look as much like a modern/plausible animal as you can!

With the feathering:

I also noticed you put the dewclaw (smallest toe) on the wrong side of the foot. It should be on the same side as the sickle claw (the inner side of the foot). Not on the outter side of the foot.

Emily Willoughby has plenty of nice paleoart of Deinonychus that showcase the animal pretty well! I recommend checking her work out if you want good examples of Deinonychus (and other dinosaur) reconstructions!