How does the mesaxonic limb structure differ from the paraxonic limb structure of artiodactyls?

The primary distinction between the limb structures of these two orders lies in the axis of symmetry through which the animal's weight is distributed:

• Mesaxonic (Perissodactyls): The weight-bearing axis passes through the third or central toe alone. This digit is the most strongly developed, and in highly specialized forms like the horse, it supports the majority of the body weight while other digits are reduced or vestigial.12
• Paraxonic (Artiodactyls): The main weight-bearing axis passes between the third and fourth toes together. Evolution in artiodactyls has favored the development of these two central toes, while the second and fifth toes have progressively declined.12

While both orders have evolved specialized limb structures to support efficient movement, the perissodactyl condition emphasizes a single central digit, whereas the artiodactyl condition relies on a paired-toe arrangement.12