The orientation of the adductor crest relative to the fibular and tibial condyles should be revised according to the actual location of these condyles - see comment to figure 5.

Fibular condyles and tibial condyles reversed on all figures. Fibular condyle located posteriorly, ventral to fibular fossa. Tibial condyle located mostly anteriorly but also a bit posteriorly.

"cap" on figure B should be "ect".

The holotype and only known skull of Ko. prima is horribly overprepared; I don't think the former presence of lateral-line grooves can be determined.

Bulanov VV. 2003. Evolution and systematics of seymouriamorph parareptiles. Paleontological Journal 37:S1–S105.

Thanks for alerting me of Bulanov (2002), by the way; that's a reference I had overlooked!

Sure, Coloraderpeton was (lateral-line canals: Pardo et al., 2017), but phlegethontiids (of which Sillerpeton is one) were not – two have been found on a fossil forest floor that was covered by volcanic ash, without any water being involved in the deposition. References and some discussion in Marjanović & Laurin (2019).

Klembara J. 2009. New cranial and dental features of Discosauriscus austriacus (Seymouriamorpha, Discosauriscidae) and the ontogenetic conditions of Discosauriscus. Special Papers in Palaeontology 81:61–69.

Lateral-line grooves lost, quadrate ossified, neural arches swollen. Very incomplete specimen, though.

"(but see Marjanović & Laurin, 2019 for alternative phylogenetic placement)"

We found the seymouriamorphs in the exact same position as almost everyone else. Instead, what got an "alternative phylogenetic placement" were the lissamphibians; they are what determines whether the branch the seymouriamorphs are on is the amniote stem or the tetrapod stem.