Procoelocryptodira

Cast of skeleton of the Cretaceous Toxochelys latiremis, from Oceans of Kansas.

Belongs within: Centrocryptodira.
Contains: Trionychoidea, Emydidae, Testudinoidae, Cheloniidae, Dermochelyoidae.

The clade Procoelocryptodira includes all living cryptodire turtles and tortoises except for the Chelydridae. Procoelocryptodira have smaller tails than other cryptodires, with small or absent haemal spines and procoelous central articulations (Gaffney & Meylan 1988). They can be divided between the marine Chelonioidea, and the freshwater or terrestrial Chelomacryptodira. Characterising features of the chelonioids include elongation of the forearm digits three and four, with flattened carpals and tarsals and a straightened humerus. The Chelomacryptodira are united by a strong temporal emargination of the skull, with a small postorbital bone, limited parietal postorbital contact, and usually no postorbital-squamosal contact (Gaffney & Meylan 1988).

<==Procoelocryptodira
    |--Chelomacryptodira GM88
    |    |--Trionychoidea GM88
    |    `--Testudinoidea GM88
    |         |--Emydidae GM88
    |         `--Testudinoidae GM88
    `--Chelonioidea GM88
         |  i. s.: Corsochelys GM88
         |         Rhinochelys GM88
         |--Toxochelys [Toxochelyinae] GM88
         |    `--T. latiremis GM88
         `--+--Ctenochelys [Lophochelyinae] GM88
            `--Euchelonioidea GM88
                 |--Cheloniidae GM88
                 `--+--Notochelone costata Owen 1882 GM88, F71
                    |--Allopleuron GM88
                    |--Desmatochelys GM88
                    `--Dermochelyoidae GM88

*Type species of generic name indicated

REFERENCES

[F71] Fletcher, H. O. 1971. Catalogue of type specimens of fossils in the Australian Museum, Sydney. Australian Museum Memoir 13: 1-167.

[GM88] Gaffney, E. S., & P. A. Meylan. 1988. A phylogeny of turtles. In The Phylogeny and Classification of the Tetrapods, vol. 1. Amphibians, Reptiles, Birds (M. J. Benton, ed.) pp. 157-219. Clarendon Press: Oxford.