Belongs within: Chelonioidea.
The Cheloniidae are the group containing living sea turtles with the exception of the leatherback Dermochelys coriacea. As well as their marine habits, distinctive characters include a platycoelous articulation between the sixth and seventh cervical vertebrae (Gaffney & Meylan 1988).
<==Cheloniidae
| i. s.: Tasbacka Nessov 1987TH02
| |--*T. aldabergeni Nessov 1987TH02
| `--T. ouleabdounensis Tong & Hirayama 2002TH02
| Catapleura ruhoffi Weems 1988TH02
| DollochelysB93
| |--D. atlantica (Zangerl 1953) [=Toxochelys atlantica]B93
| `--D. casieriS87
| Chelyopsis littoreusF91
|--Carettini [Carettidae]GM88
| |--ProcolpochelysGM88
| |--Colpochelys kempii Garman 1880F13, JPG04 [=Lepidochelys kempiiF13]
| |--Lepidochelys Fitzinger 1843GM88, C18
| | `--L. olivacea (Eschscholtz 1829)JPG04
| `--Caretta Rafinesque 1814C18
| |--C. caretta (Linnaeus 1758) [=Testudo caretta]JPG04
| | |--C. c. carettaC18
| | `--C. c. gigasC18
| |--C. imbricataH04
| |--C. olivaceaF13
| `--C. remivaga Hay 1908F13
`--CheloniniGM88
|--Natator McCulloch 1908F13
| `--N. depressus (Garman 1880)C18 [=Chelonia depressaF13; incl. *N. tessellatus McCulloch 1908F13]
|--Eretmochelys Fitzinger 1843GM88, C18
| `--E. imbricata (Linnaeus 1766)C18
| |--E. i. imbricataC18
| `--E. i. squamataC18
`--Chelonia Sonnini & Latreille 1802C18
|--‘Chelone’ cuneicepsF13
|--C. imbricata [=Chelone imbricata, Testudo imbricata]R13
`--C. mydas (Linnaeus 1758)I92 [=Testudo mydasJPG04, Chelone mydasF13]
|--C. m. mydasBF88
|--C. m. agassiziM94
|--C. m. caranigraBF88
`--C. m. japonicaC18
*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.
[BF88] Bishop, M. J., & A. E. Friday. 1988. Estimating the interrelationships of tetrapod groups on the basis of molecular sequence data. In: Benton, M. J. (ed.) The Phylogeny and Classification of the Tetrapods vol. 1. Amphibians, Reptiles, Birds pp. 33–58. Clarendon Press: Oxford.
[C18] Cogger, H. G. 2018. Reptiles and Amphibians of Australia updated 7th ed. CSIRO Publishing: Collingwood.
[F91] Freess, W. B. 1991. Beiträge zur Kenntnis von Fauna und Flora des marinen Mitteloligozäns bei Leipzig. Altenburger Naturwissenschaftliche Forschungen 6: 3–74.
[F13] Fry, D. B. 1913. On the status of Chelonia depressa, Garman. Records of the Australian Museum 10 (7): 159–185, pls 19–22.
[GM88] Gaffney, E. S., & P. A. Meylan. 1988. A phylogeny of turtles. In: Benton, M. J. (ed.) The Phylogeny and Classification of the Tetrapods vol. 1. Amphibians, Reptiles, Birds pp. 157–219. Clarendon Press: Oxford.
[H04] Haeckel, E. 1899–1904. Kunstformen der Natur. Bibliographisches Institut: Leipzig und Wien.
[I92] Iwahashi, J. (ed.) 1992. Reddo Deeta Animaruzu: a pictorial of Japanese fauna facing extinction. JICC: Tokyo.
[JPG04] Joyce, W. G., J. F. Parham & J. A. Gauthier. 2004. Developing a protocol for the conversion of rank-based taxon names to phylogenetically defined clade names, as exemplified by turtles. Journal of Paleontology 78 (5): 989–1013.
[M94] Moritz, C. 1994. Defining ‘evolutionarily significant units’ for conservation. Trends in Ecology and Evolution 9 (10): 373–375.
[R13] Roux, J. 1913. Les reptiles de la Nouvelle-Calédonie et des îles Loyalty. In: Sarasin, F., & J. Roux (eds) Nova Caledonia: Forschungen in Neu-Caledonian und auf den Loyalty-Inseln. A. Zoologie vol. 1 pt 2 pp. 79–160. C. W. Kreidels Verlag: Wiesbaden.
[S87] Sullivan, R. M. 1987. A reassessment of reptilian diversity across the Cretaceous-Tertiary boundary. Natural History Museum of Los Angeles County, Contributions in Science 391: i–iv, 1–26.
[TH02] Tong, H., & R. Hirayama. 2002. A new species of Tasbacka (Testudines: Cryptodira: Cheloniidae) from the Paleocene of the Ouled Abdoun phosphate basin, Morocco. Neues Jahrbuch für Geologie und Paläontologie Monatshefte 2002 (5): 277–294.