Texacephale langstoni
Texacephale langstoni is a small pachycephalosaur from Texas. Pachycephalosaurs are the so-called 'bone-headed' dinosaurs; their skulls are capped by a thick mass of bone that forms a sort of helmet over the top of the head. Only a few of them were previously known from Texas, all pretty scrappy.
In 2008, one of my colleagues, Julia Sankey, was working in the Big Bend region of Texas, in Big Bend National Park. Along with her was Darren Tanke, and they were visiting a quarry that had produced Agujaceratops (left). While looking through the quarry, Darren came across a small round nodule that bore a resemblance to a pachycephalosaur dome. He picked it up, turned it over, and the reason for the resemblance became clear; it was a pachycephalosaur dome.
The dome didn't look too great at first, but after we cleaned it up it looked quite a bit better. Still a bit beat up, with a big hole in the top of the head (some sort of pathology) but complete enough to get a picture of what it was, which features it shared with other animals, and which features it didn't. After comparisons with pachycephalosaur domes from Canada and Montana, it became pretty clear that this was something new.
When we went back at the end of 2008, I found another one weathering out of the ground. Pretty beat up, unfortunately, but as far as we can tell it probably comes from Texacephale as well.
An interesting anecdote- there's a lot of argument about what these domes are for. One argument is 'species recognition'. This doesn't really make a lot of sense to me; it's not like most animals have all that much trouble figuring out whether they're the same species or not, to the point that they'd need to evolve elaborate structures to do that. The other idea is that they rammed each other, going (literally) head-to-head in shoving matches and head-butting duels. At any rate, when I was travelling through an airport with the specimen, the TSA decided to weigh in. To be fair, I was in a pissy mood... sometimes I'm kinda irritable, particularly when I get up at 5:00 and haven't had my coffee and am about to miss my flight because the screening is taking so long etc, etc.Anyway, they notice this large, dense object in my carry-on bag. They decided that the structure could make a pretty effective weapon if, for instance, you banged it against the plane window. That doesn't seem terribly likely to me- those windows are tough and I doubt you could get through before a fellow passenger put you in a headlock. Plus, a laptop weighs just as much and would make just as effective a weapon. But logic is not something that is effective in dealing with Homeland Security. I ended up missing my flight and had to put it in the checked baggage, where I spent the next few hours in fear of the thing being lost. It ended up making it OK... but certainly Homeland Security supports the idea that these are weapons, and not just for show.
Texacephale isn't a very big animal; it's about the size of a dog. One of the interesting things about it is that it's distinct from contemporary species found to the North; another piece of evidence in favor of endemism of the dinosaur fauna in Texas. Texacephale inhabited a lush lowland environment; predators probably included dromaeosaurs, young tyrannosaurs, and the giant crocodylian Deinosuchus.