Golden Notback
The Golden Notback split from its ancestor and eliminated its ties to water. Its skin contains keratin, which helps it avoid dessication, and the gaps between some parts of its exoskeleton have closed for additional support. It has become a biped with an alternating gait, as this is more efficient than tripodal locomotion. It managed this with additional supportive armor and adjusted proportions which place its center of gravity over its semi-erect legs. Like a Terran monitor lizard, it is fairly active despite its ectothermy; still, it must bask in the sun to warm up. It is not a fast creature, due in part to the weight of its bony exoskeleton, but it doesn’t have to be in this early age of low competition. A gap in its armor forms a tympanic ear, which allows it to listen for food or potential rivals. It is a generalist omnivore, basically eating whatever it can get its toothy tentacles around in its environment whether it be fauna, flora, other, or carcass.
Like its ancestor, the Golden Notback is a burrower. In the colder parts of its range it burrows to hibernate over winter, while elsewhere it simply burrows to have a place to sleep. It is most active at dawn and dusk. To solve the problem of laying eggs on land, it has developed an eggshell; this shell is not nearly as effective as an amniote’s eggshell, so it must still find a way to keep the eggs somewhat moist. It solved this by laying the eggs in its burrow, which is naturally more moist than the surface.
Despite the changes to its anatomy and the transformation of its tail back into a tail, the Golden Notback retains its fin—now repurposed for releasing excess heat, intimidating rivals, and impressing potential mates. Its distinctive coloration serves a similar purpose. With no predators, and with all its prey having poor eyesight, nothing stopped it from going for gold and ruby red. The vibrancy of its coloration makes it highly attractive, as good colors indicate good health.
Unlike its ancestor, the Golden Notback rarely fights over burrows, having so much more space available to it for digging them. However, it will fight for the right to mate. Two males will interlock their tentacles, not actively trying to harm one another more than just trying to intimidate the other into leaving; however, the female may still choose the loser if the winner is overly aggressive or visibly unhealthy.