Scientists said that behavioural and anatomical differences meant they should be considered a new species.

In addition to anatomical differences, these two receptors also have distinctive functional differences.

There are anatomical differences between the limbs of plantigrades, like humans, and both unguligrade and digitigrade limbs.

The distinctions between foveal (sometimes also called central) and peripheral vision are reflected in subtle physiological and anatomical differences in the visual cortex.

However, some anatomical differences identify the turtle as a more basal member of the sea turtle superfamily.