Stegosaurus stenops

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Stegosaurus stenops
“Narrow-faced covered / roofed reptile”

Height: 3.1 meters
Length: 7.8 meters
Weight: 4.8 tonnes
Specimen Name: Marie


Stegosaurus is a household name amongst dinosaur enthusiasts both big and small, and for good reason! Stegosaurids as a clade have some of the most defining dinosaurian traits: dorsal plates / spikes and the thagomizer. The arrangement and function of the plates is a debate dating back to Stegosaurus‘ discovery in the late 1800s by Othniel Charles Marsh; he hypothesized the plates would be arranged in a manner similar to that of a pangolin, where they covered the entire animal.

This is where the name Stegosaurus comes from: “covered (or roofed) reptile.” Of course this restoration is outdated. S. stenops and its sister species S. ungulatus have somewhere in the neighborhood of 18-24 plates (depending on who’s counting) that run along the back in a loosely-alternating pattern after the first few on the neck. Here, Marie is shown with the plate arrangement based on the subadult Sophie specimen currently housed in London, which has an astounding >80% completeness!

Despite being comparatively smaller in size to some other herbivores that shared this animal’s habitat (BrachiosaurusBrontosaurusDiplodocus, etc.), Marie and the rest of her kind were rather successful, low-browsing ornithischians. The recent find of further neck vertebrae extends the stationary feeding range of this genus, allowing it to stand in one place and clear a larger volume of plant matter than it would with the typically-renditioned stubby neck.

[Most text recycled from earlier Stegosaurus posts.]


Artist’s Notes / Updates:

This Stegosaurus is one of many that I’ve restored, but this is the most active pose I’ve given one. She’s poised and ready to strike at a moment’s notice, so it’s best to keep your distance! I expedited a steg post because this animal plays a pivotal role in my upcoming short story Chasing Dragons (as do T. rex and Triceratops, but I’ll get to those guys…eventually).

The runny, blotchy pattern on her plates is primarily based on the extant lizard genus Heloderma–with some notable members including the Gila monster and the Guatemalan beaded lizard. I felt those spunky critters would be nice to paint her plates around. There’s also a very subtle set of spots and bands embedded in the greener parts of her skin inspired from alligator lizards (genus Elgaria).

I’ve updated my website to feature my newer digital pieces to reset my “continuity,” and I’m soon going to upload my favorite physical sketch work. Keep an eye for that.

Also, I have a new “Links” page that contains all of my social media as well as my Ko-Fi and Red Bubble. Thanks for your support, you lovely humans. x

Until next time!

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Baryonyx walkeri

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“See, not a T. rex!
“How is THIS better?!”
– Claire Dearing (Bryce Dallas Howard) and Franklin Webb (Justice Smith) in Jurassic World: Fallen Kingdom, in reference to a charging Baryonyx.

Baryonyx walkeri
“Walker’s heavy claw”

Height: 2.5 meters
Length: 7.5 meters
Weight: 1.7 tonnes
Specimen Name: Leedy



Baryonyx
was a medium-large(ish?) theropod from Cretaceous Europe. During its heyday, some 130 million years ago, this dinosaur lived alongside famous contemporaries such as Iguanodon and Neovenator. It is best known for having substantial evidence of a semi-aquatic (or at least water-lovin’) lifestyle. Many of its anatomical features point to this, from the pointed crocodile-like (or egret-like) snout to the giant recurved claw on its first finger that could grow to a foot (0.328 meters) in length. Oxygen isotope analyses (yes, even the chemists are in this) further suggest that Baryonyx and its spinosaurid kin spent more time in or around the water relative to other theropods.

These adaptations allowed Baryonyx to subsist on mostly fish, but the fossilized remnants of juvenile Iguanodon bones in its gut suggest it might’ve had a more complicated diet. This could either mean scavenging or hunting behavior, but I’m afraid I can’t really ask the dinosaur what it was up to on that fateful day. Baryonyx likely evolved to spend more time in or near the water as a response to a high number of competing predators in its environment (here’s a nice list of ’em). Taking to the water reduces the chances of conflict, and this niche partitioning story is very similar for (if not identical with) Spinosaurus and other relatives.

However, despite the long laundry list of reasons why and how spinosaurids would evolve a semi-aquatic lifestyle, the degree of which these taxa were dependent on the water is still contested. Recent literature on calcium isotopes and computer-modeled buoyancy (Hassler et al., 2018; Henderson, 2018) seem to liberate spinosaurids to more terrestrial habits, suggesting that both a significant amount of their diets were comprised of herbivorous dinosaurs and they were no more or less capable of swimming than less-specialized theropods. Both points are still hotly debated (more so the second than the first), as more direct anatomical analyses continue to point to living in shallow water (Ghilardi et al. 2018).

What we’re trying to tell you is that you should still probably run away from this thing in the off-chance that you encounter it in some derelict ranger compound with lava pouring from the ceiling.



Artist’s Notes & Introducing The Menagerie:

It’s been a long time since I’ve done a spinosaurid, and this is my first-ever digital Baryonyx illustration. I’ve been meaning to draw one of these puppies for ages, but I never got around to it. This is also my first post to the blog with my new art style. I haven’t abandoned the lineless, kind of molded look from my older illustrations, but line art and some nice rendering lets more personality flow through. Someone commented on my Instagram that this bary “looks like he’s [she’s] in trouble.”

This was originally just a practice sketch, but then it got blown waaaay out of hand into the dinosaur you see above. I primarily employed the basic watercolor, crayon, pastel, airbrush, textured pen, and rough pencil brushes from Clip Studio Paint. The pose is original, but I did roughly match proportions to Scott Hartman’s skeletal.

Now onto some not-so-real things…

For those of you who don’t know, The Menagerie is my passion project. It’s going to be a series of short stories and vignettes that culminate into a larger novella. I’m working on the first couple of entries, but the entire project has been around since 2014. It’s taken on a number of incarnations over the years. I’d love The Menagerie to be a solid entry in the “dinosaur island” genre of fictional media. However, I wanted to emphasize all the parts of this genre that I enjoy as a scientist. The Lost World: Jurassic Park and Peter Jackson’s King Kong are some of my favorite “dino island” sci-fi films because they showcase ideas of an anachronistic ecosystem. Likewise, the European traveling exhibit “Dinosaurs in the Wild” and the TV show Prehistoric Park have touched on a fascination of studying paleo critters in a modern setting.

So, I’ve hybridized these ideas. The basic premise of The Menagerie is as follows:

The United Nations has set up a research facility on an island in the Pacific that’s dedicated to studying the genetically-engineered fauna and flora that inhabit it. No one’s quite sure how these organisms were created or who was behind it. All that’s left are ruined buildings from the past that are mostly inaccessible. The UN’s fortified research campus, known as The Menagerie, regularly sends expeditions into the island interior to learn more about the biology and ecology of the extinct critters. Hijinks ensue from mysterious venomous dinosaurs to trying to round up and capture the world’s last T. rex.

The Menagerie will focus on a unique perspective. Many entries in the “dino island” genre focus on the hubris of mankind and what happens when things go wrong. Well, what happens when things go right? This series promises to bring an exciting and thoughtful plot that aims to educate and entertain.

Keep an eye out for the first two short stories: Poison Kiss and Chasing Dragons.

The Paint Paddock website will be home to my writing. If you’re interested, please stay tuned!

Until next time.

Ankylosaurus magniventris

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Ankylosaurus magniventris
“The great-bellied fused reptile”

Specimen Name: Rosalynn (female)
Specimen Height: 1.70 m
Specimen Length: 8.43 m
Specimen Weight: 4.45 tonnes

Ankylosaurus was among one of the last thyreophoran dinosaurs to ever exist, persisting through the Maastrichtian to witness the Cretaceous-Paleogene extinction event (also known as the smashy space rock event). Had this species survived, it’s likely they would’ve gone on to become the United States of America’s mascot over the bald eagle — simply by virtue of being literal walking tanks. 3-5 rows (depending on where on the body and who you ask) of bony osteoderm nodes covered the animal’s back.

The business end of an Ankylosaurus led to a large tail club, which was likely used for smashing inconveniences such as territorial rivals or tyrannosaurs. If that wasn’t enough, the final third (or so) of the caudal vertebrae were interlocking and reinforced, meaning the animal wielded the biological equivalent of a blunt handheld mace (only, y’know, on its tail).

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This is Borealopelta. Like other nodosaurs (a branch of ankylosaurs), they lacked Ankylosaurus‘s clubbed tail. Image by Davide Bonadonna, courtesy of National Geographic.

In situations where both the armor and club tail didn’t do the animal any favors, ankylosaurs employed the use of a specific kind of camouflage called countershading, where the top of the animal was much darker in coloration than the underside. This helps break up the animal’s outline in certain environments (it’s particularly popular with fish). Our understanding of dinosaur coloration has exploded in recent years; a dinosaur related to Ankylosaurus known as Borealopelta was found to have traces of pigmentary structures left behind that indicate a counter-shaded pattern. This means that armor wasn’t enough to defend these dinosaurs.

Kinda makes you glad whatever was stalking these things is long gone too, yeah?

Ankylosaurus, despite being the largest and arguably the most famous of its taxonomic clade (unless you know a six-year-old who will tell you of EuoplocephalusNodosaurusPolacanthus, and other “armored bois”) is quite different from its cousins (Arbor and Mallon 2017):

  • Their teeth are comparatively tiny; they don’t follow an otherwise very well-fit linear model correlating ankylosaur teeth to overall body size
  • Their nostrils (“nares” if you’re a fancy science person) faced outwards instead of forward
  • Their armor is configured…uniquely
  • A comparatively narrower tail club and shorter tail length compared to other ankylosaurs

Arbour and Mallon present some interesting thoughts on ankylosaurus’s ecology. These animals might’ve been diggers, not unlike modern boars and such, that churn up the ground after roots and invertebrates. Extrapolated muscle anatomy could also be in line to support this hypothesis. This makes perfect sense when you consider the orientation of their nares and their very wide mouth; these things were not particularly picky with what they were eating. Maybe they were also nest raiders? Not even the most dedicated hadrosaur mother could stop a hungry anky snacking on her new clutch. It makes for an interesting mental image, doesn’t it?

Artist Notes:

This is the first Ankylosaurus (and thyreophoran, period) in a very long time. My last rendition is from December 2016.

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It definitely feels dated.

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My new Ankylosaurus incorporates overall better rendering, body proportions, and musculature. The armor arrangement is again based on the work of Arbour and Mallon (2017). I’ve had a few correspondences with Ms. Arbour via Twitter over the multi-month process to create this tanky beast. Not that it took all that time to draw one. I just kept getting busy. The underlying skeletal structure that functions as the base for this restoration is by “getawaytrike” on Twitter and DeviantArt.

I’ve taken inspiration from members of testudines, who may or may not be archosaurs. They can have some pretty funky patterns on their shells. I decided to not go totally all-out on the anky (since, remember, they might’ve had some cryptic colorations in accordance to new science), but it could be something to look at for males.

Dilophosaurus wetherilli

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Dilophosaurus wetherilli
“[John] Wetherill’s double-crested reptile”

Specimen Name: Ellen (female)
Specimen Height: 1.85 m
Specimen Length: 6.88 m
Specimen Weight: 399 kg

Dilophosaurus is one of the few pre-Upper Jurassic theropods to have any sort of cultural impact. Unfortunately, it is known for all the wrong reasons.

Source: NBC Universal

Nothing in the fossil record yet points to dilophosaurs having extendable frills or venom; the presence of either character is unlikely (I’d like to highlight that it’s not impossible, but very improbable). While I appreciate Michael Crichton and Steven Spielberg’s attempts at making Dilophosaurus a unique animal (I especially laud their choices of color — Dilophosaurus had two prominent display crests for a reason, y’know?), most of the distinguishing characters can be written off as a by product of gene-splicing and other genetics tomfoolery. I think it’s rather unfortunate that the book and film ignore some of the animal’s true quirks that are actually reinforced by fossil evidence and comparative anatomy.

The strange notch between the premaxilla and maxilla is hypothesized to be indicative of fish-eating tendencies. Similar facial structures are found in other dinosaurs famous for heavily suggested aquatic lifestyles (spinosaurids). Dilophosaurus lived in floodplains that, at the height of the wet season, would see plentiful rivers and lakes stocked with fish and other small morsels (it was surely capable of taking invertebrates, smaller dinosaurs, small mammals, etc.).

Dilophosaurus was a contemporary to early and still-developing dinosaur taxa such as SarahsaurusScelidosaurus, and Coelophysis, a foreshadowing of the later species that would flourish during the Upper Jurassic. Until the evolution of the more recognizable mega-theropods (such as AllosaurusCeratosaurus, and Torvosaurus), this was the among the largest (known) theropods in its time.

Artist Notes:

It’s been a year (and change) since my last Dilophosaurus restoration (first image below).

Dilophosaurus

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Adjustments from then and now include:

  • Refined feather cover (based on similarly-built theropods like Ornithomimus)
  • Color palette overhaul; crests a warm color instead of cool (there are still blue accents)
  • More active posture; Ellen’s presented in a threat display with open-mouth vocalizations (hissing)
  • Overall lighter build
  • Enhanced scale and feather textures

Ellen was born of about a month of sitting around and sketching in my spare time. I took four weeks off from digital art to get back to my roots and study structure, especially how muscles and ligaments attach around the base skeleton. I’m very happy with her, and I look forward to a more reinvigorated art strategy!

Also, I have a male (myself) and female (personal friend Kayla David) silhouette once again!

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Yay for representation!

Spotlight: Tyrannosaurus rex

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Tyrannosaurus rex
“Tyrant reptile king”

Specimen Name: Regina (female)
Specimen Height: 4.12 m
Specimen Length: 12.02 m
Specimen Weight: 8.11 tonnes

Tyrannosaurus rex — a name “irresistible to the tongue” (according to Robert Bakker) — has been famous from the start. This animal captured the imagination of the public from the very start. An early-1900s New York Times paper describes it as “the king of kings in the domain of animal life.” And now, T. rex remains among the most popular dinosaurs to enthusiasts and laypeople alike; it ranks highly among other favorites such as TriceratopsBrontosaurusVelociraptor, and Stegosaurus. As such, it is also one of the most scrutinized dinosaurs to interest groups. Was it a scavenger? Was it an active hunter? Was it endothermic? Was it ectothermic? Was there a middle ground? Were the arms useless? What was its bite force? How fast could it run? Could it even run?

Many of these questions have close answers, but I rest my case that Tyrannosaurus is still heavily argued over more than a century after its discovery.

Paleontologists have made strides during that century of study, evolving our perception of Tyrannosaurus from a slow kangaroo-posed reptile to a (relatively) agile and rather birdlike predator. Recently, tyrannosaur integument (skin covering — i.e. bare skin, feathers, scales, keratin plates, and so on) has started to become a topic of interest. The uncovering of Yutyrannus — a tyrannosauroid* from China covered from head-to-tail with feathery down — set an interesting precedence in artistically restoring large tyrannosauroids. However, developments made by Bell et al. suggest that the possible feather “real estate” for Tyrannosaurus rex proper is less substantial than previously thought. Fossilized scale impressions from Tyrannosaurus rex and other related large tyrannosaurs carry the implication that these taxa were predominantly scaly. The paper does not suggest large tyrannosaurs lacked feathers. The authors do suggest that, if feathers were present on the animal, they’d be most likely placed on the dorsal side of the body (the “top”).

This was the first time that scale impressions of Tyrannosaurus & co. were formally described in scientific literature. Paleo artist Mark Witton presents a supplementary argument for adaptive integument (carrying further from one of Bell et al.’s proposals that scales in advanced tyrannosaurs were derived from early tyrannosauroid feather covering) where tyrannosaur taxa integument could change on a population-by-population or even within the same individual over time. The Bell paper is still under tough scrutiny by paleo enthusiasts and professionals everywhere. As one block of text in a sea of comments suggested, “It’s not that T. rex couldn’t be feathered. It’s just the likelihood of scales has increased.”

*Tyrannosauroidea is a taxonomic grouping one step above Tyrannosauridae.

Artist Notes:

Hooooooooo-boy.

This was a tough dinosaur to get through. Not because it was particularly challenging (I’m confident enough with tetanuran theropods to freehand most of ’em), but rather I was unsure of how it’d be received. I was pleasantly surprised to have this animal be my most popular on my Instagram account.

This version of Regina takes some major departures from previous incarnations, the most obvious of which is the lack of a protofeather coat. She does have filaments on her body (top of the neck and on the arms). She also sports a yellow-olive-tan pelt as opposed to my bread-and-butter brown and white. The blue highlight around the eye was a last-minute addition; it’s also unintentionally reminiscent of Jurassic World‘s Baryonyx artwork. I swear it’s a coincidence; great minds think alike.

Regina has a fairly tall keratin “crest” on her snout. This is influenced by ancestral tyrannosauroids such as Guanlong, which had crests with a bony core (not entirely dissimilar to Dilophosaurus). Evidence of vascular structures along the top of the head supports the existence of some type of keratin structure. Another feature I added was taken from Daspletosaurus. Carr et al. published some writing involving facial scales that were analogous to crocodilians.

This is also the first animal I’ve restored with reflective lighting/shading (I refer to both, collectively, as “dynamic overlays”) with greens, blues, and yellows representing where light from the ground, sky, and sun would be hitting the animal from all angles. The effect is subtle, but present.

Spotlight: Brachiosaurus altithorax

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Brachiosaurus altithorax — High-chested arm reptile

Specimen Name: Eclipse (female)
Specimen Height: 14.2 m
Specimen Length: 20.1 m (neck erect)
Specimen Weight:  33.2 tonnes

B. altithorax is currently the only valid species of Brachiosaurus. Most restorations seen in media (Jurassic Park films, etc.) are modelled after a similar brachiosaurid hailing from Africa — Giraffatitan brancai. Initially assumed to be a species of Brachiosaurus, compounding analyses of G. brancai dating as far back as the late 1980s have pointed to reassign the, at the time, “Brachiosaurus brancai” as its own standalone genus. The differences between the two taxa were described, in-depth, by Michael P. Taylor in 2009. Some characters that would be easiest to see in a side-by-side comparison of two living specimens would be:

  • B. altithorax having semi-splayed forelimbs due to more mass carried in the front half of the animal
  • B. altithorax having a longer+taller tail
  • G. brancai having a more “gracile” appearance, whereas B. altithorax would be the more visually-massive/”robust” animal

(You can read more in the link above, if interested.)

Other synapomorphies (traits scientists use to identify related species from a common ancestor) within B. altithorax and G. brancai that were originally thought to be only characteristic of the genus Brachiosaurus have also been found to be more widely-distributed amongst similar sauropods, meaning that as the pool of discoveries expanded, the traits that supposedly unified B. altithorax and G. brancai together became less and less unique across the spectrum. Extinct animals are kind of a mess when it comes to taxonomy since they’re, well, dead.

Brachiosaurus specimens have been found in the Morrison Formation in the midwestern USA. Here, they have proven to be one of the rarer dinosaurs found in this locale (sharing similar distributions to other uncommon sauropods such as Barosaurus). The reason for this is unknown. Other contemporary sauropods such as Apatosaurus, Camarasaurus, and Diplodocus are much more common finds. With relatively scant material (and an incomplete skull), not much is known about this species of brachiosaur.

However, one of the more interesting things about the holotype (the “example”/”base” individual) B. altithorax is that it’s likely not fully grown. Taylor describes the coracoid (a process near the shoulder blade) as not fused, indicating immaturity and the possibility of much greater growth, had it survived to adulthood. Projections already place Brachiosaurus near the 12-15-meter mark in height, but with this finding in conjunction to more evidence of rather extreme gigantism in some other sauropods (ApatosaurusBarosaurus) can push the limits even further.

Artist Notes:

Brachiosaurus is my favorite dinosaur of all-time. I typically have “tiers” of favorite dinosaurs (love ’em, like ’em, hate ’em), but the top of the pyramid is this gal. Its supposed rarity in the floodplains of Jurassic USA would’ve made it quite the treat to see in a hypothetical paleo-safari setting. As such, I tried to make the animal much more distinctive than my older restoration made in January:

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(Don’t get me wrong, I still love her colors. They’ll be repurposed for another sauropod.)

Besides the color adjustments, I also had the legs “mesh” better with the body with added skin and muscle attachments (particularly for the hind limbs). A row of spines down the dorsal is also a prominent new feature. I’ve retained some quills on the head and tail, but removed them from the arms in favor of large tubercles. Brachiosaurids are Titanosauriformes, whose members have quite variable integument. Saltasaurus, while not directly related/descended from B. altithorax by any means, had protective bony plates within the skin. It’s not unreasonable that other Titanosauriformes would have similar deterrents to predators.

June is also #PrideMonth. I’ve taken the liberty to include grey, white, black, and purple onto the new brach to represent motifs from the demisexual flag. You can deduce the reason why if you add 2 and 2.

Spotlight: Deinocheirus

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Deinocheirus mirificus — “Peculiar horrible hand”

Specimen Name & Sex: Oscar (male)
Specimen Height: 5.44m
Specimen Length: 14.5m
Specimen Weight: 10.5 tonnes

Deinocheirus is one of the strangest dinosaurs to ever be discovered. Looking like a chimera between a hadrosaur, camel, and a duck, its true heritage lies with the ornithomimosaurs; it was related to the fast-moving “ostrich dinosaurs” such as GallimimusOrnithomimus, and Struthiomimus. Its massive 2.4-m arms puzzled scientists for half a century (it was even named after ’em!), and it was not until the early 2010s that scientists pieced together its likely placement in the dinosaur family tree. Another striking characteristic of this taxon is the “hump” of raised vertebral processes, which has been compared to that of Spinosaurus’ sail or bison humps. The purpose of this structure is still largely unknown; even I offer no hypotheses to explain the growth.

Oscar occupied an ecological niche unlike that of any one living animal today. As a swampland/shoreline inhabitant, he would’ve enjoyed a fairly variable diet consisting of fish and presumably soft aquatic vegetation. Evidence of this omnivorous lifestyle was uncovered in the form of preserved fish scales and gastroliths (rocks and other hardened substrate swallowed to aid in digestion of plants) associated with a Deinocheirus specimen.

Artist Notes:

This enigma of a dinosaur has been equal parts interesting and irritating to research and illustrate. It’s a ridiculous creature with gangly proportions and, as mentioned prior, has no living analogs. To reflect this, I upped the strangeness with speculative filter-dentition inspired from flamingos and baleen whales, which is one of my prouder original speculations. I also debated to give Oscar webbed feet, but I felt his kind would be ill-suited to full submersion and would likely prefer to wade through the water. Other ornithomimosaurs were found to possess pennaceous feathers on the tail, implying a tail fan of sorts. I neglected to include this feature on this highly-derived taxon. If future developments suggest it retained a tail fan similar to its cousins, I’ll add it (written as of 5 April, 2017).

Skeletal reference by Scott Hartman

Spotlight: Stegosaurus

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Stegosaurus stenops — Narrow-faced covered reptile

Specimen Name & Sex: Jean (female)
Specimen Height: 2.8m
Specimen Length: 6.4m
Specimen Weight: 2.7 tonnes

Stegosaurs are among the most charismatic of all dinosaurs. Where tyrannosaurs have tiny limbs, ceratopsids have spiky head ornamentation, sauropods have long necks, and hadrosaurs have “duck bills,” stegosaurs have some of the most defining “dinosaurian” traits; the dorsal plates and the thagomizer. The arrangement and function of the plates is a debate dating back to Stegosaurus‘s discovery in the late 1800s by Othniel Charles Marsh. Marsh hypothesized the plates would be arranged in a manner similar to that of a pangolin, where they covered the entire animal. This is where the name Stegosaurus comes from — “covered reptile.” Of course this restoration is outdated. S. stenops and its sister species S. ungulatus have somewhere in the neighborhood of 18-24 plates (depending on who’s counting) that run at least semi-bilaterally along the animal’s back. I have elected to keep the plates as display structures, disregarding hypotheses of temperature regulation due to the probable existence of a layer of keratin covering the vascular structures. Here, Jean is shown with the plate arrangement based on the subadult Sophie specimen currently housed in London, which has an astounding >90% completeness!

She’s also not much larger than Sophie. S. stenops was the smaller of the two recognized species of Stegosaurus, with mass estimates close to that of a rather porky rhinoceros. Despite a comparatively smaller size to some contemporaries (BrachiosaurusBrontosaurusDiplodocus, etc.), Jean and the rest of her kind were rather successful, low-browsing ornithischians. The recent find of further neck vertebrae extends the stationary feeding range of a steg, allowing it to stand in one place and clear a larger volume of plant matter than it would with the typically-renditioned stubby neck.

Skeletal reference by Scott Hartman.

Artist Notes:

What strikes me the most about the new Stegosaurus is the strange plate arrangement along with the proportionality of said plates. To an extent, they appear asymmetrical as opposed to the more traditional reconstructions with a very clear, very concise shift in size from the neck to the hip and then tapering towards the end of the tail. It’s come to my attention that I also might’ve placed the plates too low, so Jean might get a refurbishment in the near future (nothing major, just adjusting the plates and maybe her head). Maybe a pattern update, too?

The duality of the blue and pinkish tones on Jean is something I consider to be my trademark for Stegosaurus. I interpret stegosaurs to be docile, rather skittish animals. The big eyespots on the plates were meant to deter attacks from predators, with the thagomizer acting as a last resort. The thagomizer was no laughing joke, however. The strength of the tail was more than capable of lodging a spike deep into any opposing party. I complemented the tail spikes with some sharp keratin barbs, just in case the animal lost or broke a spike in combat.

Spotlight: Pachycephalosaurus

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Pachycephalosaurus wyomingensis — Wyoming’s thick-headed reptile

Specimen Name: Gracy (female)
Specimen Height: 1.67m
Specimen Weight: 450kg
Specimen Length: 4.98m

One of the most striking things about Pachycephalosaurus is the character that this species is named for — its skull. At the thickest point, the bone was close to 22cm (~9 in) thick. This initial observation sent scientists running to the quickest conclusion they could make: the head was a weapon. Though some doubt has been cast in the time after the initial hypotheses were formed, a well-constructed analysis by Peterson et al. suggests that pachycephalosaurids with dome heads (as opposed to the flatheaded varieties/morphs) frequently confronted one another in antagonistic behaviors. In this study, the same kind of skull lesions/fractures were found between many different pachycephalosaurs across different geographic areas. In addition, Horner et al. found that the skull dome was made of bone known to have fibroblasts (cells that aid in rapid bone regeneration). Plenty of head injuries + a means to heal them => something ahead of its time.

Pachycephalosaurus is also one of the last non-avian dinosaurs to have ever existed. Specimens are known to be found in America’s Hell Creek Formation — a fossil bed known for specimens such as Tyrannosaurus rexTriceratops prorsus, and so on. All of these taxa existed right until the very end of the Cretaceous, to the event known as the K-T boundary extinction. It and its famous contemporaries struggled and failed to survive the aftermath.

Artist Notes:

Pachycephalosaurus is an animal that I’m not unfamiliar with. This is actually my…sixth(?) or seventh time restoring one. For reference, this was my most recent pachy otherwise:

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Some of the things I’ve retained from this to the new pachy are as follows:

  • The color palette (primarily yellow and tan)
  • The cluster of filaments at the end of the tail, accented with a bit of blue and white
  • Filaments on the forearms

The quills/filaments/feathers on this animal are largely speculative. As far as I know, we’ve no direct skin impressions from a pachycephalosaur (I’m writing this 3 March, 2017. If any developments/discoveries are made, I’ll update this.), so integument is largely a task left to phylogenetic bracketing. Ceratopsids and pachycephalosaurs are placed in their own monophyletic group, dubbed “Marginocephalia.” Basal ceratopsids such as Protoceratops and Psittacosaurus are known to have long bristle-like filaments on the tail. Assuming the common ancestor of both pachycephalosaurs and ceratopsids had similar traits, it’s not so strange to think a pachycephalosaur could retain at least some bristle ornamentation.

I made the clumps of bone at the back of the skull pointier in the March ’17 pachy. This is to reflect more recent findings of pachycephalosaur development, particularly in the skull shape. In life, I assume these sharp pseudo-horns(?) would be used to cause superficial injuries to an opponent. Assuming the animal swung its head (as opposed to the straightforward impact as seen in modern rutting animals) like a club, the additional movement of pulling the skull back to a neutral pose had the potential to scrape/cut as well. The head dome is also very brightly pigmented, which is simply something of my own design.

Gracy is depicted in a near-tripodal pose, crouching on her legs to rear her upper torso high. She’s bleating, sending a call to fellow pachycephalosaurs. I don’t imagine these to be exactly social animals, which might’ve formed loose family-based clusters, at best. She would only be vocalizing to ward off intruders to her territory, to find mates, or simply to check if there are others of her kind in the area. The snarl/bleating of the Jurassic Park Pachycephalosaurus is fairly close to what I envision for my renditions