Paleontologists who study archosauriformes like to focus on the ankles and in particular the calcaneal "heel." To most of them, if you have that bone, you can classify the entire animal. To a certain extent, they have a point. More importantly, though a large analysis, like this one, reveals patterns in the shapes of that "heel" that have gone largely unnoticed.
Most paleontologists prefer their dinosaur ancestors to not have a calcaneal "heel" at all. That's why they like pterosaurs, Lagerpeton and Scleromochlus in that position. Unfortunately, if they take one step out from those taxa, they run into phylogenetic "brick walls," taxa that don't look anything like these three.
This study includes many more specimens in order to provide many more slots in which the specimens may nest, reducing the chance of any "by default" nestings and increasing the resolution of the entire tree.
Here the calcaneal heel has phylogenetic patterns that can be traced and followed. Turfanosuchus had a calcaneal heel that turned proximally because its direct ancestors shared this character. Certain side branches lost it. Certain descendents lost it. See the entire tree here.