Crêpe Sturge
In response to increasing predation from R. occisorostrus and S. vexus, S. opscuruclavis took its "low profile" approach even further, resulting in the comically flat S. sturgendeficere. Sturgendeficere is still 15 centimeters in length, but has distributed most of its mass laterally, being almost as wide as it is long. As a result, it managed to get its body to a mere 1 centimeter thick.
Like its ancestor, sturgendeficere spends its time lying on the muddy substrate of Zone 10 eating detritus. Instead of sifting around and actively pursuing food, sturgendeficere lies flat on its back with its mouth open, eating whatever particulate matter happens to flow into its mouth. When it has found a suitable spot to lie down, it will very rarely move, some specimens spending their entire lifespan lying in the same spot. Because it camouflages well with the substrate and rarely moves, predators often pass on by none the wiser. This behavior became widespread for this reason-- Lazy sturges feeding in this way were less likely to be killed, and the technique persisted through generations.
Once in place, sturgendeficere flaps its fins against the substrate to cover itself with mud. Should predators see through its many layers of disguise, its flat body makes it very difficult for them to pick up-- Like trying to chomp down on a wet piece of paper. Its tail flukes have disappeared, and its tail has gotten wider, eliminating a potential weak point for predators to grab onto. Even if it is grabbed, sturgendeficere doesn't panic, but remains still until the predator (hopefully) loses interest or has their fill of non-vital tissue (e.g. fins).
The only time sturgendeficere stirs is when it comes time to mate. Like their ancestor, males flip right-side up and swim around furiously until they detect a resting female with their whiskers. Eggs are laid at the base of polyphs, and covered with a thin layer of mud to hide them from predators. Batches vary from 30-50 eggs.