So thereâs a challenge being run by Wyatt Andrews on twitter and instagram called #DinosThroughThe Decades, the aim being to compile a timeline of our scientific understanding of one prehistoric species as represented through palaeoart! I decided to do Stegoceras validum, since I feel like itâs gone through a lot of changes that arenât appreciated as they should be! And so, hereâs my breakdown of each drawing in this timeline:
The year in which Stegoceras was described, as Stegoceras validus, by Lawrence Lambe. The identity of the fossil was pretty much completely up in the air at the time, since all we had of it at that point was the dome of the skull:
One of the conclusions that Lambe reached, and the one Iâve gone with here, is that the dome was the base of a large single horn on the snout of a ceratopsian dinosaur. There is sadly no actual palaeoart depicting Stegoceras like this, so I based my reconstruction heavily on Charles Knightâs beautiful ceratopsian illustrations from the 1890s and 1900s.
By 1918, Lambe was now suggesting that Stegoceras was not a ceratopsian, but a member of the group stegosauria, which included ankylosaurs and stegosaurs and is now known as thyreophora. He even erected a new clade for Stegoceras, psalisauridae, which did not last long.
This was probably the toughest one for me to work out since the brief is basically âa thick-headed 1910s-style generic thyreophoranâ, and I ended up working mostly from Knightâs Stegosaurus and improvising the armour. That said, itâs a wonderfully weird concept and itâs one of my favourite end products!
We finally know what the rest of Stegoceras looks like! Charles Gilmore described a complete skull and partial skeleton of Stegoceras, and very helpfully for me it included a skeletal diagram!
But yes, the small birdlike elephant in the room: Gilmoreâs description reassigned our beautiful bumpy-head boy to the now-considered-dubious tooth taxon âTroodonâ. This ended up with the kinda confusing situation of having what is now known as pachychephalosauridae being grouped under the name âtroodontidaeâ, which now refers to a clade of dromaeosaurs. Even after the clade name was changed, new pachycephalosaurs were still being described as species of âTroodonâ all the way into the 1950s!
The way that palaeontology viewed dinosaurs was beginning to alter during the 70s and 80s, and dinosaurs were starting to run faster and lift their tails up off the ground. The last few decades had been good for pachycephalosauridae too, with new fossils showing a much greater scope of the groupâs diversity in North America and Asia, and âTroodonâ finally being ejected from the group as recently as 1987 by Phil Currie.
My main inspiration for this one was these awkward dinosaur book illustrations from around this era that just seem kinda off. Either itâs something about how cylindrical and formless the limbs are, or the stiffness in the pose, but I find them charmingly odd. They look very much like plastic dinosaur toys.
The Dinosaur Revolution is in full swing at this point, and dinosaurs are tending to look leaner, meaner, and kinda in need of a decent meal. The 90s and the 2000s really form a bit of a single era in dinosaur palaeoart, with dinosaurs in wiry muscle and skin and not much else, often adorned with spikes and osteoderms and the occasional single spiny dewlap. It was a weird time and of all of them this one was the hardest to draw faithfully and correctly without feeling like I was making a parody.
And finally, my comfort zone! The impact of the book All Yesterdays on the trajectory of modern palaeoart is truly hard to understate, since it basically pushed weird, experimental palaeoart into the mainstream palaeo consciousness. Moving on from the almost literally bare bones dinosaurs of the 2000s, weâve started rounding out or dinosaurs a bit, and inferring speculative structures and behaviours from what we observe in the fossil record and in the world around us!
The details of integument including quills but also the foot scales and skin on the legs are inferred from the absolutely stunning Psitaccosaurus specimen from a few years ago, since itâs really the closest species we have to pachycephalosaurs that preserves those details.
I think a big part of the culture shift around palaeoart in the last few years is the acknowledgement that we as palaeoartists can never reconstruct a species 100% accurately, and that there is room for interpretation and speculation. If youâre guaranteed to be wrong anyway, you might as well experiment and try out new things, so long as it doesnât contradict the things that are knowable!
And thatâs brought us all the way through almost 120 years of Stegoceras validum, and also 120 years of cultural and artistic evolution in the way we look at and understand dinosaurs! Thanks for sticking with me, I hope you enjoyed the ride!
