It turns out that the creature we’ve been calling “Brachiosaurus” — the one with the super-weird nostrils on top of its concave head — is not the same clade as every other one we’ve called Brachiosaurus for the last century. No, the one with the weird nostrils (not, as I was taught, for snorkeling as a submarine gargant, as it would have been unable to breathe with all that water pressure) is now called a Giraffatitan. Which is a pretty wonderful name.
It’s quite possible that Giraffatitan could reach some 20 meters in height. The one I’ve pictured here is a reconstruction from an existing specimen which is known to be adolescent.
You’ll notice some differences between this sketch and the previous one. The biggest difference is that this one seems like it has bones and muscles. I’d oversimplified the previous sketch, and it made it really look like one of the dinosaurs of my childhood: awkward, slow, and composed of shapes with little relationship to each other.
But these were living things that thrived in a time when Earth had much more oxygen in its atmosphere, and so animal life was not only bigger, but probably more lively. Forest fires would rage among the giant palms and conifers. Flying insects could grow as large as a dog. And animals like Giraffatitan could exist in huge herds.
Of course, this reconstruction study, taken from Nima Sassani’s skeletal reconstruction, does some speculation, based on a synthesis of things we know with things I want.
- I’ve put that big, bulbous nose on top of the weirdly concave skull. It’s a resonating chamber for honking to other members of the herd and, you know, sounding sexy. There’s a now-discounted hypothesis that Giraffatitan had a trunk, but, as much as I like that weirdness, it just doesn’t have the muscle attachments for it the way elephants and elephant seals do.
- Its lower body is camouflaged to break up its profile in the underbrush of ferns. You might think that such a huge animal wouldn’t be able to be camouflaged, but its predators were likely large therapods just a third its size. And, since they lived in herds, camouflage helps by making it hard for a predator to see exactly which animal is which, and what direction they’re facing. The vertical lines are to blend in with vertical plants.
- The tall neck, however, is mottled to look a bit like a cedar tree. Again, enough to confuse predators in the heat of the moment.
- There’s a subtle eyespot on its head, making it look as though it’s looking down even when its eyes are closed, to make therapods uncertain about whether they have the element of surprise.
- The long spines down the neck, back, and tail haven’t been found on Giraffatitan examples, as far as I know, but they’re on pretty close relatives, and they give me a way to make sauropods a little flashier. They weren’t embedded deep in the bones or anything, so perhaps they were for holding up a sail to help keep the critter cool, since, without an elaborate cooling system, the interior of a sauropod would be hotter than the temperature of cooking meat. We know that they literally breathed through their bones to keep them cool, though! I’m imagining that they’re a display thing here, plus a way to make it hard for a therapod to get up on the Giraffatitan’s back.
- That big, S-curving neck might be wrong. Some reconstructions have it sticking out straighter, but it seems to me that it doesn’t have a heavy enough tail to counterbalance that huge neck. When I did my reconstruction of the Isisaurus Colberti, I could feel when the tail was wrong because the model kept trying to do handstands.
And, oh, hey, look down by the front feet. That’s the size of you and me.
I think I’ve finally got a handle on the physiology here, though I need to do some sketches of the feet (weird wrist bones! They look wrong no matter what I do! No current animals have that configuration!) and the head to come to a full understanding. Next up on this project is thinking about actual composition for the book cover that this will turn into!