Testudinata

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.[2] A recent phylogenetic tree of Testudinata included Angolachelonia and Testudines as sister-taxa and subgroups of Testudinata.[3]

Testudinata Temporal range: Late Triassic - Holocene, 210–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N Possible Early and Middle Triassic records in the form of fossil tracks[1]
Skeleton of Proganochelys quenstedti, American Museum of Natural History
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Pantestudines
Clade:	Testudinata Klein, 1760
Subgroups
†Australochelys †Chinlechelys †Proterochersis †Palaeochersis †Proganochelys Mesochelydia

Classification

The cladogram below follows an analysis by Jérémy Anquetin in 2012.[2]

†Odontochelys    Testudinata    †Proterochersis     †Proganochelys       †Palaeochersis     †Australochelys       †Kayentachelys     †Indochelys     †Sichuanchelys     †Chengyuchelys     †Chuannanchelys     †Eileanchelys       †Heckerochelys     †Condorchelys         †Naomichelys     †Otwayemys       †Mongolochelys    †Meiolaniidae    †Niolamia       †Ninjemys     †Meiolania               †Kallokibotion     Testudines (modern turtles)

References

1. 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.
2. 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.
3. Evers, S. W., & Benson, R. B. (2018). 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.