Temnospondyl evolution (Fortuny and Steyer 2019)

Adding taxa and reviewing scores
are slightly modifying the cladogram of basal tetrapods (Fig. 1), distinct from traditional cladograms.

Fortuny and Steyer 2019 report:
“Phylogenetic analysis of a large dataset (72 taxa, 212 characters) focuses on the in-group relationships of temnospondyls, the largest lower tetrapod clade. The following groups were unequivocally found to be monophyletic: Edopoidea (node), Dvinosauria (stem, excl. Brachyopidae), Dissorophoidea (node), Eryopidae (stem), and Stereospondyli (node). In all variant analyses, edopoids form the basalmost temnospondyl clade, followed by a potential clade (or grade) of small terrestrial taxa containing Balanerpeton and Dendrerpeton (‘Dendrerpetontidae’). All taxa higher than Edopoidea are suggested to form the monophyletic stem taxon Eutemnospondyli, tax. nov. The remainder of Temnospondyli fall into four robust and undisputed clades: (1) Dvinosauria; (2) Zatracheidae plus Dissorophoidea; (3) Eryopidae; and (4) Stereospondyli.”

By contrast
the large reptile tree (LRT, 1447 taxa, subset FIg. 1) finds Balanerpeton closer to reptiles and dvinosaurs closer to basalmost tetrapods. So Fortuny and Steyer’s traditional in-group includes out-group taxa.

Figure1. Subset of the LRT focusing on basal tetrapods, modified from earlier versions by adding taxa and re-scoring after better data was found.

Figure1. Subset of the LRT focusing on basal tetrapods, modified from earlier versions by adding taxa and re-scoring after better data was found. Here amphibians are temnospondyls and mammals are amphibians, by definition. Nomenclature needs to be reviewed. 

The traditional clade Stereospondyli
is paraphyletic in the LRT.

The traditional clade Eutemnospondyli (Schoch 2013)
is paraphyletic in the LRT.

Amphibia, by definition,
now includes Reptilomorpha, Reptilia, Mammalia and Primates.

Tetrapodomorpha requires a contrast with
lungfish (clade: Dipnoi) and coelacanths (clade: Actinista), which need to be added to the LRT.


References
Fortuny J and Steyer J-S 2019. New insights into the evolution of temnospondyls. Journal of Iberian Geology. https://doi.org/10.1007/s41513-019-00104-0
Schoch RR 2013. The evolution of major temnospondyl clades: an inclusive phylogenetic analysis. Journal of Systematic Palaeontology 11(6):673–705.

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