[1] Before Pappochelys was discovered and Eunotosaurus was redescribed,[2] Odontochelys was considered the oldest undisputed member of Pantestudines (i.e. a stem-turtle).

The locale of its discovery at one time was the Nanpanjiang Trough basin, a shallow marine environment surrounded on three sides by land.

[4] One of the most striking features of turtles, both modern and prehistoric alike, are their dorsal shells, forming an armored carapace over the body of the animal.

[4] Aside from the presence of teeth and the absence of a solid carapace, a few other skeletal traits distinguish Odontochelys as basal compared to other turtles, extant and otherwise.

Taken together, these anatomical differences have been interpreted by the discoverers to mean that Odontochelys has some of the most primitive features ever seen in a turtle and is somewhat of a transitional fossil.

Since it is generally accepted that the shell arose to provide protection against predators, the semi-aquatic nature of turtles and the development of the plastron complement each other.

In addition, Joyce (2015) argued that even if Odontochelys was semiaquatic, it probably would have avoided open marine waters due to a lack of efficient adaptations for swimming.

This condition has been observed in diving animals which are forced to make rapid ascents within a deep marine environment.