Diandongosuchus. Not a basal poposauroid. A basal phytosaur.

The most recent JVP included a paper by Li et al. (2012) described a new “archosaur” from the marine Triassic of China, Diandongosuchus fuyuanensis. Their phylogenetic analysis, based on Nesbitt (2011) nested their find at the base of the poposauroidea. That was not confirmed by the large reptile tree. Rather Diandongosuchus nested at the base of the Phytosauria.

This was such an open-and-shut case that this poor nesting is a further indictment of the Nesbitt (2011) tree. More details on this very exciting discovery of a VERY basal phytosaur coming soon.

Reference
Li C, Wu X-C, Zhao L-J, Sato T and Wang LT 2012. A new archosaur (Diapsida, Archosauriformes) from the marine Triassic of China, Journal of Vertebrate Paleontology, 32:5, 1064-1081.
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.

4 thoughts on “Diandongosuchus. Not a basal poposauroid. A basal phytosaur.

  1. Of the 17 characters Li et al. found placing Diandongosuchus in Poposauroidea, how many are included in your analysis?

    Of the characters placing Diandongosuchus with phytosaurs in your analysis, how many aren’t related to subaquatic habitats (e.g. long low snout; posteriorly placed external naris…)?

    • I don’t know. I never correlated what is and what is not subaquatic. I”ll get there. I just found the paper yesterday. You don’t see the family resemblance to phytosaurs (especially in the calcaneum and coracoid)?

  2. Your tree itself is not a datum. When comparing phylogenetic trees, as in the literature, analysis of character cohesion and inclusiveness is taken up. Yo showed in your past review that you did not include quite a number of Nesbitt et al. characters, especially with statements equating to “I can’t review this character as such,” when dealing with features of the braincase, et al. This then turns to “my output is different from their output.” When saying “X is not Y, but is Z,” one must present not only why it is not Y, but also Z. So far you’ve said the first, but not quantified this, and thus the statement is useless.

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