by chelsea schuyler
Can we just talk for a second of the rockindom of the Stegosaurus? Those plates, what’s going on there?
The boxer brief: The history of our impressions of the Stegosaurus is, as so many human trains of thought, somewhat humiliating. Stegosaurus means “roof lizard” because we used to think the plates laid flat over its back like roof tiles. We now believe they stood upright (in effect raising the roof, and maintaining name integrity).
Instead of lummox-y monsters melting in the swamp of their own claymation, we now see a dignified, agile creature that might actually stand a chance against Jason AND the Argonauats. Stegosaurus had large deltoid (yeah I said deltoid) muscles for quick side-stepping, pivoting on its back legs and swinging a flexible tail that held those famous spikes.
The tailspikes are called the “thagomizer” which is the awesomest name ever, and I kid you not, was coined by the GENIUS Gary Larson in a 1982 Far Side strip. It stuck, and is now official paleontology slang.
Paleontologist Robert Bakker thinks the Steg was perfectly built to support a tripod stance, rearing up on its back legs and tail, kangaroo style. Being tall gets you a lot more leaves on those pesky conifers of the day (and as we all know, short people got no reason to live). The Stegosaurus body worked a lot like a crane–the hind legs and heavy tail like the base of the crane (where the construction dude sits) and the head and forelegs like the …picky uppy, neck part of the crane. I don’t know, I don’t do cranes. And there are virtually no pictures of the Stegosaurus doing this on the net, it’s very aggravating, but it’s kinda like this:
This video, though painful, as nearly all modern media portrayals of dinosaurs are (save Jurassic Park), is actually a fairly well done depiction of the Stegosaurus according to modern theory. Tripod eating habits, high tailin it, and pivoting on the back legs to quickly shift their position. Also, extensive footage of the Stegosaurus naturally blanketed in the warm comforts of John Goodman.
So, about those triangles, what the hell? They are called osteoderms, bone-like structures of the skin, basically giant scales. What were they for? As usual, we don’t know. Incoming Scientific Speculation alert!!
1) sexual attraction. the somewhat disappointing but relevant (cop-out) theory. Not something you can really go farther with when dealing with the extinct. Stegosaurus mating–there’s only guessing as to how that worked. ow. Paleontologists would kill to get a “handle” on Stegosaurus “love triangles,” which has always been a “prickly” subject.
2) armor. sure, anyone best be keepin dey munchin face outta that whole area. So yeah, that could be intimidating to a predator, but the armor theory has fallen quite out of favor. Their backs just don’t need the extra defense. The vertebra of a Stegosaurus has massive spines thought to provide purchase for extra muscle to support that whole crane position. Note the vertebral spines in comparison to ours:
In The Dinosaur Heresies Robert Bakker claims that “Any Allosaurus unwise enough to bite into that ridge would have broken off its teeth without inflicting significant damage.” Breaking teeth off. I don’t why that’s so amusing to me. can we get the sound fx guy on that?
Anyway, Bakker thinks the plates’ angles were adjustable, able to swing out to the sides a bit to better stave off a predator from its vulnerable flanks. This wouldn’t work on say, a crocodile (who have the same kind of back, with little mini plates), as their plates are firmly lodged width-wise in the tough skin. A Stegosaurus plates only just sits atop that skin, and could have left room for muscle manipulation.
3) thermoregulation. You know an elephant’s giant ears? The thin skin is filled with blood vessels that can absorb heat from the sun or cool off from a breeze or by fanning. Some scientists think the plates serve the same function, as they do have large blood vessels running through them. But if this is the case, some species got the short end of the stick, having only thin spines instead of plates. Not enough surface area to do much . Hmm
Oh to know what we’ll think in another 100 years! Meanwhile, the little people have their fun. Colorado has wisely named the Stegosaurus the state fossil. Wait, we have state fossils?? What’s Oregon’s?
The Dawn Redwood. A friggin tree, that A) still exists and B) is not even native! They thought it was extinct but then they found a grove in China, Bogarted the seeds and now it’s all over the country. Nothing against trees or anything, but seriously? To see if your state is as lame as ours, check out this website.
Meanwhile some sewer guys found a dinosaur fossil in D.C. and named it Capitalsaurus. sigh. And then the government had to go all Declaration on it and created the Official Dinosaur Designation Act of 1998, of which Section 4 states: “This act shall have no fiscal impact.” Really? That has nothing to do with, it’s not even, we spend time on this? I mean there’s even a part where they specify that if the mayor vetoes it the Council will override and OH MY GOD PEOPLE
This blog shall have no pituitary impact.