Testudinata is the group of all tetrapods with a true turtle shell. It includes both modern turtles (Testudines) and many of their extinct, shelled relatives (stem-turtles). Though it was first coined as the group containing turtles by Klein in 1760, it was first defined in the modern sense by Joyce and colleagues in 2004. Testudinata does not include the primitive stem-turtle Odontochelys, which only had the bottom half of a shell. A recent phylogenetic tree of Testudinata included Angolachelonia and Testudines as sister-taxa and subgroups of Testudinata .
|Skeleton of Proganochelys quenstedti, American Museum of Natural History|
The cladogram below follows an analysis by Jérémy Anquetin in 2012.
- Asher J. Lichtig; Spencer G. Lucas; Hendrik Klein; David M. Lovelace (2018). "Triassic turtle tracks and the origin of turtles". Historical Biology: An International Journal of Paleobiology. 30 (8): 1112–1122. doi:10.1080/08912963.2017.1339037.
- Anquetin, J. R. M. (2012). "Reassessment of the phylogenetic interrelationships of basal turtles (Testudinata)". Journal of Systematic Palaeontology. 10: 3–45. doi:10.1080/14772019.2011.558928.
- Evers, S. W., & Benson, R. B. (2019). A new phylogenetic hypothesis of turtles with implications for the timing and number of evolutionary transitions to marine lifestyles in the group. Palaeontology, 62(1), 93-134.