Teyujagua paradoxa: still no paradox in the LRT

Back in 2016 Pinheiro et al.
introduced readers to a small Early Triassic proterosuchid without much of an antorbital fenestra, Teyujagua paradoxa (Fig. 1). Back then a smaller large reptile tree (LRT, subset Fig. 2) nested Teyujagua as one of several smaller descendants of Proterosuchus without an antorbital fenestra. Based on taxon exclusion Pinheiro et al. 2016 mistakenly described Teyujagua as, “transitional in morphology between archosauriforms and more primitive reptiles…as the sister taxon to Archosauriformes.” Evidently they were looking for greater glories than Teyujagua actually represented.

Figure 1. Teyujagua compared to sister taxa, including Youngoides, Proterosuchus and Chasmatosaurus. Teyujagua is a phylogenetic miniature in which the antorbital fenestra became a vestige.

Figure 1. Teyujagua compared to sister taxa, including Youngoides, Proterosuchus and Chasmatosaurus. Teyujagua is a phylogenetic miniature in which the antorbital fenestra became a vestige.

 

This year (2019) Pinheiro et al. returned to Teyjagua
They wrote, “The evolution of the archosauriform skull from the more plesiomorphic configuration present ancestrally in the broader clade Archosauromorpha was, until recently, elusive.”

This is a bogus statement.
The LRT found a series of terrestrial younginiforms basal to archosauriforms and protorosauria. You read about them here in 2011. All the authors had to do was google Teyjagua to find the data needed to overturn their hypothesis.

Pinheiro et al. 2019 continue, 
“This began to change with the discovery and description of Teyujagua paradoxa, an early archosauromorph from the Lower Triassic Sanga do Cabral Formation of Brazil. In addition to providing new details of the anatomy of T. paradoxa, our study also reveals an early development of skull pneumaticity prior to the emergence of the antorbital fenestra.”

This is an backwards statement.
The LRT found Teyujagua was losing an antorbital fenestra, not gaining one. Adding taxa would have solved this problem for Pinheiro et al. 2019, as suggested three years ago.

Pinheiro et al. 2019 continue,
‘The data presented here provide new insights into character evolution during the origin of the archosauriform skull.”

The actual origin of the archosauriform skull
according to the LRT (Fig. 2). occurs in a list of excluded taxa ending with Youngoides romeri FMNH UC1528. As before Teyujagua remains a sister to Chasmatosaurus alexandri NMQR 1484 and is therefore a dead end taxon, basal to nothing.

Figure 2. Cladogram of basal archosauriforms. Note the putative basalmost archosauriform, Teyujagua (Pinheiro et al 2016) nests deep within the proterosuchids. The 6047 specimen that Ewer referred to Euparkeria nests as the basalmost euarchosauriform now.

Figure 2. Cladogram of basal archosauriforms. Note the putative basalmost archosauriform, Teyujagua (Pinheiro et al 2016) nests deep within the proterosuchids. The 6047 specimen that Ewer referred to Euparkeria nests as the basalmost euarchosauriform now.

This should be embarrassing to the authors
when an amateur without a science degree of any firsthand access to  the specimen can tell the PhDs they didn’t included enough taxa to understand what they were dealing with. Sadly, this is not the first time, and it won’t be the last. The LRT is a powerful tool, free for all to use.

Figure 1. Youngoides romeri FMNH UC1528 demonstrates an early appearance of the antorbital fenestra in the Archosauriformes. This specimen is the outgroup to Proterosuchus, the traditional basal member of the Archosauriformes. 

Figure 3. Youngoides romeri FMNH UC1528 demonstrates an early appearance of the antorbital fenestra in the Archosauriformes. This specimen is the outgroup to Proterosuchus, the traditional basal member of the Archosauriformes.

Figure 3. Click to enlarge. Updated image of various proterosuchids and their kin. When you see them all together it is easier to appreciated the similarities and slight differences that are gradual accumulations of derived taxa.

Figure 4. Click to enlarge. Updated image of various proterosuchids and their kin. When you see them all together it is easier to appreciated the similarities and slight differences that are gradual accumulations of derived taxa. Teyujagua is a deadened taxon, less glorious than Pinheiro et al. 2016 and 2019 wish it was.

A paper on Youngoides romeri and the origin of the Archosauriformes
can be read online here at ResearchGate.org. It was rejected by the referees.


References
Pinheiro FL, França MAG, Lacerda MB, Butler RJ and Schultz CL 2016. An exceptional fossil skull from South America and the origins of the archosauriform radiation. Nature Scientific Reports 6:22817 DOI: 10.1038/srep22817.
Pinheiro FL, De Simao-Oliveira D and Butler RJ 2019. Osteology of the archosauromorph Teyujagua paradoxa and the early evolution of the archosauriform skull.
Zoological Journal of the Linnean Society, zlz093
https://doi.org/10.1093/zoolinnean/zlz093
https://academic.oup.com/zoolinnean/advance-article-abstract/doi/10.1093/zoolinnean/zlz093/5585773

https://pterosaurheresies.wordpress.com/2016/03/13/teyujagua-not-transitional-between-archosauriforms-and-more-primitive-reptiles/

 

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