>>6095695>>6096444These guys develop spiracles to intake oxygen, the crests stay because the females like them a lot so they remain as a signal of a fit mate. The increased oxygen allows them to begin to rapidly increase in size like the large arthropods in our own timeline. The armor keeps them from drying out on land and the increased oxygen means they don't suffocate on land so they transition to a terrestrial lifestyle, snacking on the eyeball plants. I would like to suggest the name Squilla Cristata for this guy which is latin for crested shrimp
