SVP 2018: Pelycosaurian phylogeny (should not include Caseasauria!)

Wilson, et al. 2018
discuss various issues with pelycosaurian phylogeny, but then make the mistake of including Caseasauria, an unrelated clade in the large reptile tree (subsets in Figs. 1, 2).

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.

Figure 1. A monophyletic Pelycosauria if we can accept the changes suggested in the text.

Figure 1. A monophyletic Pelycosauria without the Caseasauria, which nests in the basal Lepidosauromorpha (see figure 2) when more taxa are added.

Adding 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.

Figure 2. Subset of the LRT: basal lepidosauromorpha, featuring Caseasauria.

Figure 2. Subset of the LRT: basal lepidosauromorpha, featuring Caseasauria. Pelycosaurs nest in the basal archosauromorpha when more taxa are added.

References
Wilson WM, Angielczyk KD, Peecock B, Lloyd GT 2018. Pelycosaurian “lineages”: a meta-analysis of three decades of phylogenetic research. SVP abstracts.

Metaanalysis 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, metaanalysis can be used to identify this common effect.

From the first post on this subject back in 2011:

The case for taking Caseasauria out of the Synapsida.

Figure 3. Which of these skulls does NOT belong with the others. The case for taking Caseasauria out of the Synapsida.

 

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