An early proponent of this scenario was Goodrich (1916), who defended a diapsid origin of turtles based on morphological evidence.

[5] Lee (2001) found that forcing the turtle group to cluster with archosauromorphs resulted in Rhynchosauria becoming Testudinata's sister clade.

[6] Although morphology-based analyses usually do not support a turtle-archosaur clade (Archelosauria), Bhullar & Bever (2009) identified a laterosphenoid bone, typical of Archosauriformes, in the stem-turtle Proganochelys.

[8] Lepidosauria †Choristodera †Trilophosaurus †Rhynchosauria Archosauriformes †Eosauropterygia †Placodontia †Sinosaurosphargis †Odontochelys †Proganochelys Testudines The cladogram below follows the most likely result found by another analysis of turtle relationships, this one using only fossil evidence, published by Rainer Schoch and Hans-Dieter Sues in 2015.

Their phylogenetic analyses strongly supported Eunotosaurus's state as a stem-turtle and the placement of Pantestudines in Diapsida, though they couldn't determine a well-defined position within that clade.

[9] Benton (2015) compiled 2 synapomorphies of Ankylopoda (which would also include Sauropterygia, Thalattosauria and Ichthyosauria close to lepidosaurs): prootic-parietal contact and hooked fifth metatarsal.

[13] †Parareptilia †Captorhinidae †Paleothyris †Araeoscelidia †Hovasaurus †Youngina †Acerosodontosaurus †Claudiosaurus †Eunotosaurus †Pappochelys †Eorhynchochelys †Odontochelys Testudinata Archosauriformes †Prolacerta †Trilophosaurus †Rhynchosauria Rhynchocephalia Squamata †Kuehneosauridae †Eosauropterygia †Placodus †Saurosphargidae Gardner & Van Franken (2020) criticized the analysis by Li et al., citing problems with the data set and observing that their proposed phylogeny was not supported once the issues were corrected.

[14] Lichtig & Lucas (2021) proposed Pappochelys was related to sauropterygians, Eunotosaurus was a caseid synapsid, and turtles were derived pareiasaur parareptiles close to Anthodon.