Wednesday, 4 July 2012

DINO SORE: Triceratops

So, I've got a week off work, and not before time. Naturally, I've gone and got myself some grotty bug that's made me feel nauseous, exhausted and generally shoddy. I'm away this weekend for a friend's birthday celebrations, so hopefully I'll have a bit more energy by then. Plus, I've got to fit some Spider-Man time in there somewhere. I'd hoped to make some more writing progress this week, but it turns out that feeling rubbish is not conducive to creativity. I'm so behind on so many things that it's not even appropriate to make a Douglas Adams-style quip about deadlines. If any of you guys are reading this blog, I apologise: I swear I'll get these things done eventually.

Still, between bouts of banging my head against a brick wall, I decided that I needed to write something. So I decided on dinosaurs.

Now, I love dinosaurs. It's common to note that most young children go through a phase of dinosaur fascination; not everyone grows out of that stage. I certainly didn't. Thankfully, I have friends who share my interest, or at least, don't mind me wittering on about it at length. Plus, I can go and watch Dinosaur Train with my best friend's brood of small children. Dinosaurs - I love 'em, kids love 'em, the great browsing majority love 'em. There's some really fascinating stuff being uncovered. I just wish that the papers and news sites could be a little more careful in their reporting of these discoveries.

One of the most stupid claims I've seen recently, in several places, is that Triceratops will soon cease to exist. No such thing as Triceratops! Actually bother reading past the headlines, and you'll discover that no, of course it still exists, it's just being renamed. Actually bother to ditch the newspaper and read a more reputable resource and you'll learn that Triceratops is perfectly safe as a name. This controversy, if it can be called such, has actually been rumbling along for a while. There's been something of a gear change in the way paleontologists classify dinosaur genera. Now, generally speaking, as a dinophile you're either a lumper or a splitter. Splitters tend to want to give a distinct label to new fossils unless they can be proven to be pretty perfect matches to existing ones. This approach leads to bulging books full of fabulous dinosaur names, even though a lot of them look rather similar. Lumpers, on the other hand, take the opposite approach. Lumpers tend to bundle similar fossils together, often as multiple species of the same genus. This approach, historically, led to dozens of very different fossils all being called Megalosaurus, and fell out of favour for a while. I'm more of a lumper myself, and this trend seems to be having a renaissance.

You see, animals don't tend to stay the same all through they're lives. A kitten doesn't look exactly like an adult cat. A baby doesn't look exactly like a fully-grown man or woman. Shapes change, proportions alter. Males and females can mature in very different ways. Elephants grow tusks, stags sprout antlers. Plus, of course, individuals from the same species don't all look the same. So it came as a sudden revelation to many that dinosaurs were very probably the same. The first big name dino that got this treatment was Dracorex, and that was only well known because its specific name is hogwartsia, after the school in Harry Potter. That got it some inevitable press attention. It was suggested that the spiky-headed little Dracorex matured into the still-quite-spiky-but-not-as-much Stygimoloch, which grew up to be big, lumpy, dome-headed Pachycephalosaurus. Not everyone agrees, but it's a neat idea with a lot of support. Now, Triceratops has been the recipient of a similar suggestion. This actually became a talking point two years ago, but it's only now that the press seem interested.

Triceratops lived across what is now North America in the very late Cretaceous period, and its fossils have been found in more-or-less the same places as another, similar dinosaur, Torosaurus. The suggestion has been made that Torosaurus is simply a mature Triceratops. Triceratops does have an unusual skull, in that its closest relatives (the dinosaur subfamily known as ceratopines or chasmosaurines) tended to have tall, broad skull frills with fenestrae (i.e. windows) to make them lighter. Triceratops had a shorter, denser skull frill without these gaps, more like the sister group the centrosaurines. The suggestion is that, as it grew older, the skull got larger and developed fenestrae to take the weight off. Things have got a little more complicated since another ceratopine, Nedoceratops, was brought into the mix. This might be yet another example of a separate stage of Triceratops growth, or an example of sexual dimorphism, or an abnormal example, or a separate genus. Not everyone agrees that Torosaurus was a mature Triceratops, anyway, pointing out that specimens from different growth stages appear for both genera.

io9 has a good article about the various viewpoints, but it still insists on using the tagline that it "may rob you of Triceratops forever!" A quick glance at the facts shows that it won't. Even if all three of the above are determined to be the same genus, Triceratops has priority as the earliest used name. This is how it works - that's the reason that Brontosaurus was scrapped in favour of Apatosaurus (although the defunct name is still cropping up all over the place, even on the BBC website). The name that was first published in a scientific paper has priority, and Triceratops came first. A very good dinosaur blog, Dinosaur Tracking, has something to say on the matter. To the best of my knowledge, the only time dinosaur naming has broken with this convention is with Tyrannosaurus rex, specimens of which were once described as Manospondylus gigas. This name dates back to 1892, with T. rex only as far as 1905, so should have priority. However, it was decided that Manospondylus was a nomen oblitum, or forgotten name, that had gone unused for decades, and that the sheer weight of material for Tyrannosaurus, along with its cultural significance, granted it a protected status in any case. So, Triceratops is safe - it's just gotten more interesting, that's all.

Next time, I think, I'll start on the feathers.

No comments:

Post a Comment