Conspiracy

When wandering through the temples in Angkor Wat back in March this year, this little chap was pointed out to us. The comment from the guide was that obviously the monks in the 13th century knew about dinosaurs! It's certainly true the carving does superficially look like a Stegosaurus and it's also true that the conspiracy theorist sympathisers in the group immediately leapt on the idea as some kind of conclusive evidence, however my little skeptical brain instantly jumped to "what else could this be", there are many possibilities.

There is a genus of lizard in the arboreal forests of Asia called "Acanthosaura" all of whom have spiny or scaly back features, these animals are common in the region and it would be difficult to model small spines in limestone without precision steel tools. Alternatively this may not be a reptile at all, it could be an Elephant or Rhino (both native to the region) and the lumps on it's back may not be on it's back at all as some don't appear to be. It could be some kind of pack animal or even just the figment of the artists imagination, a chimera, as was common in that period and culture (i.e. Hindu monkey and cobra gods like Hanuman and Naga) 

The bottom line is that we don't know what it is, we'll never know and that's fine, all we have is the balance of probability which is stacked heavily in my favour. It's interesting (anthropomorphically) that for many people making up an answer is far more desirable than having none.