The trilobites, the Nautilus, and the Armored Fish were all out-and-out dominators of the ocean.
The trilobites and the Nautilus both boasted hard shells and were relatively 'huge'. They were the most terrifying killing machines in an era when most of the ancient ocean creatures were no larger than plankton.
There was no need to mention the Armored Fish. Other than its hard shell, it also possessed a swift movement ability, allowing it to charge and sweep away all prey.
But Li Yao eliminated the three seemingly tempting evolution options without any hesitation.
Because he was very clear that no matter how powerful the trilobites, the Nautilus, and the Armored Fish appeared to be, in the end, they were eliminated in the long river of time.
Their enormous size meant that they had to consume more energy in order to survive. Most of their time was spent on hunting and absorbing.
