Last week, the world was stunned by a new paper by Baron, Norman & Barrett (2017) that challenged Seeley's 130-year-old dichotomy of the Dinosauria. No longer were Saurischia and Ornithischia neatly separated. Instead, ornithischians were the sister group of theropods in a united Ornithoscelida, and sauropodomorpha (which now included Herrerasauridae as its most basal member) were spun off on their own in a weirdly lonesome Saurischia.
I spent several days writing a very lengthy post about this subject, as I considered it interesting and important. I also haven't really found the thesis statement for my WIP article on thalattosaurs.