Ankylopoda

Ankylopoda
Proganochelys quenstedti
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Sauria
Clade:	Ankylopoda Lyson et al., 2012
Extant Subclades
Testudines Lepidosauria

Ankylopoda is a clade that contains turtles and lepidosaurs (Tuatara, lizards and snakes) and their fossil relatives. This clade is supported based on microRNAs^[1] as well as the fossil record.^[2] Stem-turtles and lepidosaurs have unique skull elements and features not seen in archosaurs (represented by extant crocodilians and birds).

Classification

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. This study found Eunotosaurus to be an actual early stem-turtle, though other versions of the analysis found weak support for it as a parareptile.^[3]

Sauria	Archosauromorpha  Ankylopoda/Lepidosauromorpha †Kuehneosauridae Lepidosauria Squamata Rhynchocephalia  Pantestudines  †Sauropterygia †Eosauropterygia †Sinosaurosphargis †Placodontia †Eunotosaurus †Pappochelys †Odontochelys  Testudinata  †Proganochelys Testudines

See Also

Archelosauria, an alternative clade that places turtles as sister taxon to archosaurs.

References

1. Lyson, T.R., Sperling, E.A., Heimberg, A.M., Gauthier, J.A., King, B.L., Peterson, K.J., 2012. MicroRNAs support a turtle + lizard clade. Biol. Lett. 8, 104–107.
2. Schoch, R. R. & Sues, H.-D. A Middle Triassic stem-turtle and the evolution of the turtle body plan. Nature advance online publication, (2015).
3. Schoch, Rainer R.; Sues, Hans-Dieter (24 June 2015). "A Middle Triassic stem-turtle and the evolution of the turtle body plan". Nature. doi:10.1038/nature14472. (subscription required (help)).