And joining the theropods are two of the strangest dinosaurian plant-eaters, Tianyulong and Psittacosaurus.
Psittacosaurus isn't unusual by itself, but those long quills on its tail really threw scientists off, but not nearly as much as the new Heterodontosaurid Tianyulong, which has plumes on its tail as well. These structures are still being studied to determine if they really are fearthers or something else entirely, but either way they have vast implications on future dinosaur reconstruction. ^^
I didn't have ref for Tianyulong though, so its proportions are probably off; I based it off what I know about Heterodontosaurus; I may draw it more accurately later, so please look forward to it!