Brand new ankylosaur was published today. This is really wonderful news, because it's an extremely basal ankylosaur. It's from the Middle Jurassic of China, from the same formation you find guys like Gasosaurus and Mamechiosaurus. What's interesting is that this new guy, Xixianankyus (she-SHE-yan-kus) does not have the typical wide body and head full of osteoderms that later ankylosaurs have.
Rather, its skull is relatively free of osteoderms except for large scutes above the palpebral bones, which implies that that skull protection evolved to shield the eyes first before spreading around the rest of the head. The body is also covered in rows of small scutes, somewhat like the case in Scutosaurus, but they are larger than in that English taxon, and what's more, there are small triangular spikes arranged in a half-circle from shoulder to shoulder, across the back.
But that's not even the strangest thing: Xixiankyus was bipedal. Or at the very least, would not have found bipedality uncomfortable. It may have habituatially stood quadrupedally, but probably walked and ran bipedally. The really wierd detail is that Xixiankyus shows more skeletal similarities to basal ornithopods than to stegosaurs. Unless this is a case of rampant convergence, this fact renders the notion of a monophyletic "Thyreophora" moot. Stegosaurs and ankylosaurs are NOT closely related, and the later is closer to duckbills. I've only skimmed the paper, but this is pretty heavy stuff. The first specimen of Ankylosaurus was actually thought to BE a stegosaur, so...yeah. Weird.
If I find a good reconstruction, I'll post it (maybe I'll just draw my own), because this guy is rockin'!