So many millions of years ago their was a lobe finned lung fish named tiktaalik that led to the evolution of all tetrapods and the diversity they hold today. And I wanna do that again, but instead of a bony fish, I wanna use a placoderm for the job. My intention in this is to have vertebrate creatures who are virtually indistinguishable from land arthropods. Yet even after all my research into fish I still cannot find my placoderm white whale, so I am asking y'all for some help.
So my question is, what type of specific species placoderm would be best fit to crawl onto land?
Needs to be in the order arthrodira or a simular group that has self sharpening toothplates
Need to have ray fins capable of evolving a form similar to a sea robbin, allowing for arthropod like legs and wings to evolve over time
Need color vision(not sure if they all had this or just a select few?)
Need to be omnivorous