Sometimes, it can be difficult to figure out how ancient organisms used to eat. Part of the problem is that we can never actually see extinct animals eating (until we invent time-travel.. *taps fingers impatiently at physicists*), and often it can be hard to work out how something ate based just on its anatomy. Sometimes though, the fossil record chucks up something truly spectacular, and gives us amazing insight into the spectacular diversity of ancient life.
This is a post about pachycephalosaurs. It’s not a post about feathered dinosaurs, huge dinosaurs, or any of the ones which you may be more familiar with from popular media. Pachycephalosaurs were the dome-headed little scrappers of the Cretaceous, around 85 to 66 million years ago. Their name means ‘thick-skulled lizard’ (pachy: thick, cephalon: skull, saurus: lizard), and they were a small group within the larger herbivorous group of dinosaurs called ornithischians.
It’s probably fair to say that these dinosaurs are one of the least popular groups; they didn’t have razor sharp teeth and sickle-switchblade claws, they didn’t grow to the size of houses, and they didn’t have rows of armoured shields and spikes along their backs. What they did have, however, is an unusual behaviour that signifies them as unique, and pretty amazing, beasties.
Fig.1 – A pachycephalosaur suffering an ‘ouchie’, or cranial lesion (PLoS)
I’m in Berlin. I’ve just managed to find a chicken donner kebab, and am pausing research briefly to write this. I’m currently on leave from London, with a ridiculously hectic couple of months ahead: I’ve just been to Munich to see a dwarf crocodile specimen, Alligatorellus beaumonti (from Bavaria), which conveniently happened to coincide with Oktoberfest, and am now here to visit another specimen, Theriosuchus ibericus, from Spain. Preliminary glances at the material in Berlin makes me think the Spanish material may be a new genus altogether (whatever that actually means), and another broken up specimen of Alligatorellus might be a new species, based on what I can tell from it’s body armour (yeah, these crocs were awesome!)
Alligatorellus beaumonti, holotype specimen. Copyright: Bavarian State Collection, Munich
Some dinosaurs were utterly bizarre. You may have heard of them before, but one particular group called therizinosaurs belonged to the meat-eating theropod dinosaurs (those that led to birds), were really awesome. However, they actually at some point made a conscious evolutionary decision to stop being badasses, and become Cretaceous-cauliflower* munching pansies.
What comes to mind when you think of dinosaur interaction? Large carnivores chomping on unsuspecting little ornithopods? Ceratopsians jousting for their next mate? Large hadrosaurs tenderly mothering their cute newborns? There are many possible images of community-level dinosaur interactions, and there is a host of evidence out there that take dinosaurs beyond the bones and breathe new life into how they lived.