Neodiapsida

Belongs within: Diapsida.
Contains: Ichthyosauria, Lepidosauromorpha, Archosauromorpha, Testudinata.

The Neodiapsida is the clade containing the crown group of living diapsid reptiles (the Sauria) together with the basal ‘Younginiformes’ (Senter 2004). The Younginiformes are a group of lizard-like reptiles known from the late Permian and early Triassic whose monophyly relative to Sauria is uncertain. One group within this assemblage, the Tangasaurinae, was adapted to a freshwater aquatic habitat, with webbed feet and a laterally compressed tail.

Synapomorphies (from Senter 2004): posterior trunk ribs holocephalous; maximum of 17 dorsal vertebrae; pronounced olecranon process absent.

<==Neodiapsida [Younginiformes]
    |  i. s.: HeleosuchusE88
    |         Nanchangosauridae [Hupehsuchia]B93
    |           |--Nanchangosaurus Wang 1959D07
    |           |    `--N. suni Wang 1959B93
    |           `--Hupehsuchus Young 1972B93, D07
    |                `--H. nanchangensis Young & Dong 1972B93
    |         IchthyosauriaB93
    |--TangasauridaeE88
    |    |--KenyasaurinaeE88
    |    |    |--Kenyasaurus mariakaniensis Harris & Carroll 1977B93
    |    |    `--Thadeosaurus Piveteau 1926E88, D07
    |    |         `--T. colcanapi Carroll 1981B93
    |    `--TangasaurinaeE88
    |         |--Tangasaurus mennelli Haughton 1924B93
    |         `--Hovasaurus Piveteau 1926LF18, D07
    |              `--H. boulei Piveteau 1926B93
    `--+--Youngina Broom 1914LF18, E88 [incl. YoungoidesE88, YoungopsisE88]
       |    `--Y. capensis Broom 1914B93
       `--+--SauriaS04
          |    |  i. s.: Tapaya hernandesi Girard 1858DS89
          |    |--LepidosauromorphaLF18
          |    `--ArchosauromorphaS04
          `--PantestudinesLF18
               |--+--Acerosodontosaurus Currie 1980LF18, E88
               |  |    `--A. piveteaui Currie 1980B93
               |  `--Claudiosaurus [Claudiosauridae]LF18
               |       `--C. germaini Carroll 1981B93
               `--+--Eunotosaurus Seely 1892LF18, D07 [Eunotosauridae]
                  |    `--E. africanus Seeley 1892B93
                  `--+--Pappochelys Schoch & Sues 2015LF18, SS15
                     |    `--*P. rosinae Schoch & Sues 2015SS15
                     `--+--TestudinataSS15
                        `--Eorhynchochelys Li, Fraser et al. 2018LF18
                             `--*E. sinensis Li, Fraser et al. 2018LF18

*Type species of generic name indicated

References

[B93] Benton, M. J. 1993. Reptilia. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 681–715. Chapman & Hall: London.

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

[DS89] Dundee, H. A., & H. M. Smith. 1989. Nomenclatural eponym endings revisited. Systematic Zoology 38 (3): 279–283.

[E88] Evans, S. E. 1988. The early history and relationships of the Diapsida. In: Benton, M. J. (ed.) The Phylogeny and Classification of the Tetrapods vol. 1. Amphibians, Reptiles, Birds pp. 221–260. Clarendon Press: Oxford.

[LF18] Li, C., N. C. Fraser, O. Rieppel & X.-C. Wu. 2018. A Triassic stem turtle with an edentulous beak. Nature 560: 476–479.

[SS15] Schoch, R. R., & H.-D. Sues. 2015. A Middle Triassic stem-turtle and the evolution of the turtle body plan. Nature 523: 584–587.

[S04] Senter, P. 2004. Phylogeny of Drepanosauridae (Reptilia: Diapsida). Journal of Systematic Palaeontology 2: 257–268.