It’s that simple.
Adding taxa shows that Casesauria nest within the new Lepidosauromorpha derived from Milleretta, while pelycosaurs nest within the new Archosauromorrpha, derived from Varanops. The lateral temporal fenestra is convergent and appears in many caseasaur sisters and cousins (Fig. 2).
Given that, the authors report:
“We recover a monophyletic Caseasauria and Eupelycosauria.” Well, of course, they did. That happens with unrelated taxa.
going back to the origin of the Amniota (= Reptilia) would clarify issues. That’s what the large reptile tree is for. No one has to use the characters or the scoring, but it is a mistake not to use the relevant taxa revealed by the LRT.
Wilson WM, Angielczyk KD, Peecock B, Lloyd GT 2018. Pelycosaurian “lineages”: a meta-analysis of three decades of phylogenetic research. SVP abstracts.
Meta–analysis is the statistical procedure for combining data from multiple studies. When the treatment effect (or effect size) is consistent from one study to the next, meta–analysis can be used to identify this common effect.
From the first post on this subject back in 2011: