Strange Bedfellows – Nesbitt (2011) – part 4 – Parasuchus

Sometimes we miss the big picture.
Here then, for your approval and disapproval are comparisons between closest kin found by the Nesbitt (2011) tree versus those found by the large reptile tree. We started at the base with Mesosuchus. Earlier we looked at Vancleavea. Yesterday we looked at Euparkeria. Today we look at the phytosaur, Parasuchus, surrounded by Euparkeria on primitive side and the Ornithosuchidae (represented here by Ornithosuchus) and the Pterosauria led by Eudimorphodon on the derived side (Figs. 1, 2)

Figure 1. The nesting of pterosaurs in Nesbitt (2011), the current "Gold Standard" for the nesting of archosaurs and their relatives. Unfortunately, pterosaurs don't belong here, as can quickly be seen by side-by-side comparisons.

Figure 1. The nesting of pterosaurs in Nesbitt (2011), the current “Gold Standard” for the nesting of archosaurs and their relatives. Unfortunately, pterosaurs don’t belong here, as can quickly be seen by side-by-side comparisons and the other taxa need to be reordered for a better fit.

Parasuchus Kin According to Nesbitt (2011)
Here (Fig. 2) are the selected Nesbitt (2011) sisters for visual comparison. I don’t see any gradual evolution (accumulation of derived characters) here. Do you?

Pterosaur closest kin according to Nesbitt 2011.

Figure 2. The phytosaur, Parasuchus, surrounded by putative sisters according to Nesbitt 2011. Euparkeria was more primitive. Eudimorphodon and Ornithosuchus were more derived. Does anyone else see a problem here?? Why was this result NOT widely criticized? There is no gradual accumulation of derived characters here leading toward the bottom two taxa. 

Parasuchus Kin According to the Large Reptile Tree
The large reptile tree found Proterochampsa and the choristoderans, Cteniogenys and Lazarussuchus to be closer than Euparkeria and Ornithosuchus because they share a long narrow rostrum and dorsal nares among a suite of other traits.

Parasuchus and kin including Proterochampsa, Lazarussuchus, Youngina and Cteniogenys.

Figure 3. Parasuchus and kin including Proterochampsa, Lazarussuchus, Youngina and Cteniogenys. Note the dorsal placement of the naris on a narrow rostrum and the evolution of it moving posteriorly. Here the antorbital fenestra makes an appearance convergent with that seen in Proterosuchus descending from a sister to Prolacerta. Parasuchus is a terminal taxon in that only other parasuchians (phytosaurs) evolved from it. 

One look at these results brings immediate understanding that there’s something wrong in the matrix that produces such strange bedfellows.

As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.

Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.

References
Nesbitt SJ 2011.
 The early evolution of archosaurs: relationships and the origin of major clades. Bulletin of the American Museum of Natural History 352: 292 pp.

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