The Sandracos of the forest have gotten more mobile. Two powerful pairs of hindlimbs to support itself had evolve, while it's front limbs have gotten more flexible and mobile. It has forgone it's gills and evolved hardened water retaining scales. The centaur's body is divided into two sections, upper ribs and lower ribs. The upper ribs are dedicated purely for the lungs and heart. Without other organs to cramp it up the lungs can expand wide, while the heart can grow in size to effectively circulate as much blood.
The strong hind limbs and effective breathing are needed when hunting, for they hunt the various speedy s0arers and sniffal0os. With effective stamina unlike their prey, allowing them to not get tired while tiring out prey. Their upper limbs can catch prey when done, while also pinning down struggling prey to eat. Shearing their flesh with a specialized set of teeth, each unique than the other. With sharp gripping teeth at front, and back chewing teeth at the back. Though this chewing is not side to side like mammals, instead it's front to back, as their back teeth are specialized shearing teeth that grind against each other. This also keeps them sharp to effectively kill prey.
Unlike the reptiles and synapsids who evolve first laying eggs, the centaurs adapted primarily giving "birth". With fertlized eggs incubating in the female's wombs, until they are big enough to leave the womb. This has allowed them to cut all ties to the water besides hydration. Even if they give birth, they do not care or nurture their young. Which means once the young are born they are all by themselves. However they are quite adaptable and usually make it to adulthood.
Though the centaurs are extraordinarily complex for the Auroracene, they continue capitalizing on their complexity. The Archaic Centaurs will look simple in comparison to their descendants, for they still relied on the water or shells to reproduce