Procolophonids and look-alikes, like Sauropareion

A recent endaaper
by MacDougall et al. (2013) reported on the post-crania of the Early Triassic reptile, Sauropareion (Fig. 1). The description was excellent.

Unfortunately
they labeled it a procolophonid and a parareptile. That was by tradition, for the most part.

Figure 1. Sauropareion in situ from MacDougall et al 2013.

Figure 1. Sauropareion in situ from MacDougall et al 2013.

A phylogenetic analysis was performed by them (Fig. 2) to nest Sauropareion. While their test included several taxa I have not tested (everyone needs a new project for the new year), the large reptile tree found a much different nesting (color notes in Fig 2), at the base of the owenettids, and, by extension, at the base of the Lepidosauriformes, close to Paliguana.

Figure 2. Nesting Sauropareion. Here it nests correctly with owenettids, but the inclusion of pareiasaurids like Sclerosaurus, and diadectids, like Procolophon, is unwarranted, according to the results of the large reptile tree. Also, several taxa that should have been included were not, given the gamut of the inclusion set. Several basal lepidosauriformes should also have been included given their proximity in the large reptile tree. The lack of resolution may be due to the inclusion of unrelated taxa or the incompleteness of the included taxa.

Figure 2. Nesting Sauropareion. Here it nests correctly with owenettids, but the inclusion of pareiasaurids like Sclerosaurus, and diadectids, like Procolophon, is unwarranted, according to the results of the large reptile tree. Also, several taxa that should have been included were not, given the gamut of the inclusion set. Several basal lepidosauriformes should also have been included given their proximity in the large reptile tree. The lack of resolution may be due to the inclusion of unrelated taxa or the incompleteness of the included taxa.

We need to take a large look at procolphonids
Unfortunately Procolophonidae has become a wastebasket taxon for any small reptile with short toes and a large orbit. A large gamut phylogenetic analysis is needed to correctly nest the many taxa that have been attributed to it — and to correctly nest the Procolophonidae itself.

The large reptile tree nests Procolophon, Hypsognathus and Pentaedrusaurus with Diadectes, a taxon typically excluded in prior analyses.

MacDougall et al. include Sclerosaurus, but that taxon nests with pareiasaurs in the large reptile tree.

Phonodus nests with bolosaurs in the large reptile tree, not far from procolophonids and diadectids.

Assumptions and traditions
need to be tested in a larger gamut analysis. If I have any influence over the study of paleontology, this is what I want, a large gamut analysis by someone else to test the large reptile tree.

References
MacDougall MJ, Modesto SP and Botha-Brink J 2013. The postcranial skeleton of the Early Triassic parareptile Sauropareion anoplus, with a discussion of possible life history. Acta Palaentologica Polonica 58(4):737-749.

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