Updated Therapsid Tree

No big news here…
Add a few taxa…Discover that a few taxa represented by old drawings (Nikkasaurus, Niaftasuchus) actually belong elsewhere… (just outside the Synapsida).

And the therapsid subset (59 taxa) of the large reptile tree (674 taxa) gets an update (Fig. 1) with better Bootstrap scores.

Figure 3. Basal therapsid tree.

Figure 1. Basal therapsid tree, updated.

The topology remains basically the same. 
A few long-snouted basal theriodonts were added along with Phthinosuchus. The anomodonts still split off at the base of the Therapsida, following the appearance of the basal taxon, Cutleria. This tree remains distinct from predecessor trees in this basic topology, I think because more basal, pelycosaur-like, taxa are included here and not elsewhere.

There is still a lot of convergence here.
And this is probably the main reason why tree topologies don’t match.

  1. Dicynodonts and dicynodont mimics (Tiarajudens, Anomocephalus).
  2. Gorgonopsids and the gorgon-mimic Herpetoskylax (a basal burned).
  3. Basal therapsids like Stenocybus and a basal therapsid-mimic, Microurania (Fig. 2).
  4. Anteosaurs and the anteosaur-mimics Deuterosaurus, Estemmenosuchus and Ulemosuchus (Fig. 2).
  5. And more convergence among the untested taxa within the therocephalians and cynodonts.
Figure 2. Click to enlarge. Basal therapsid tree based on phylogenetic analysis and presented with skulls

Figure 2. Click to enlarge. Basal therapsid tree based on phylogenetic analysis and presented with skulls

I dug back into this tree and gathered better data
because Bootstrap scores were not robust in the prior analysis. It was an amazing two-week journey. And when better data becomes available, more refinements will attempted. At this point, the gradual accumulation of traits in all derived taxa are apparent.

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