Was the araeoscelis a eurapsid also… along with the icthyosaurs, plesiosaurs, and placodonts?
Yes all were “eurapsids”, but Arae. was from a very different lineage – therefore paraphyletic. Knowing that the animal groups you listed above are the only eurapsids we discussed will be what you need to know. Also know who were archosaurimorphs, archosaur, crurotarsi etc. (i.e. know the names along the bottom of that tree).
