Twilight Neodevorator
Constrained by its need to swim constantly, the Neodevorator split from its ancestor upon selecting for musculature that assists in taking in water as it moved into the Twilight zone, where abundant large prey and increased light levels influenced a number of further changes. Most notably, the Neodevorator is twice as large, now reaching sizes of up to 66 cm on average. The heftier abundance of prey compared with the deeper regions has allowed the organisms to feed without the need for territory, meaning that while they typically keep their distance from each other, they rarely fight, usually flashing their UV patches in close proximity until one leaves.
Due to their gill musculature allowing them to take in water without moving, the organisms can now enter states of dormancy or remain still for periods of time without risking death, allowing them to save energy - a huge bonus in the depths. The more efficient breathing also allows them to move at faster speeds, which when coupled with their streamlined form and faster air expulsion through the expulsion passage allows them to swim much faster than their relatively slow ancestors. As some of their prey items are quick and hard to catch, additional adaptations were still necessary, however. As such, the chitinous plates developed a denticle covered surface in which flecks of chitin point in the opposite direction of the water, preventing flow separation. This causes the chitin to feel smooth if something brushes it in the direction of its mouth, but rough and sandpaper-like if brushed in the opposite direction.
Much like its ancestor, the Neodevorator crushes prey to death with its muscular tentacles, though unlike before it now uses speed in conjunction with its streamlined faceplate to ram into a prey item, stunning it momentarily as it quickly grips and squeezes it to death by retracting the tentacles, causing prey to be crushed between the plates and tentacles. Its tail is heterocercal in form due to its retained long-distance traveling nature, so it often uses stamina and a steady cruising speed to catch prey such as Nektolixo, which it is unlikely to be able to match at top speed. In order to allow it to eat more food, the faceplate is segmented into 4 pieces, allowing the mouth ring to expand further when necessary. Its eye can now be covered by 4 chitinous plates that can open or close, leaving the creature blind when closed but protecting its eyes against attackers or thrashing prey. The tentacles can be retracted roughly halfway into its 4 cephalic sheaths - pockets in its head that allow it to take a more streamlined form to travel at full speed. The tentacles can retract or extend quickly, allowing it to quickly grip prey or protect itself within its exoskeleton.
Its organs are similar to those of its ancestor, however, its heart has developed an extra chamber for more efficient circulation and its simple cerebral ganglion has developed into a very primitive brain. Gelatinous fat deposits fill much of its body that is not occupied by muscles or organs, helping it to store energy for harder times. A separate, small amount of fat exists in the exoskeleton between 2 distinct layers of chitin, strengthening the armor against blows by absorbing the energy of crushing and squeezing attacks, as well as against high-strain impacts such as when ramming prey. Like before it relies on scent to locate prey. It retains its ancestral UV patches, with many more developing on the front dorsal fin in particular than before. The patches can now be dimmed and brightened, facilitating its ability to flash them as a warning to others of its species. Mating also remains mostly the same, with members of the opposite gender recognizing each other by the aforementioned patches (males also have several patches on their chitinous carapaces, females do not). The creatures will mate by clinging to each other with their back fins, with one upside down. Females will also release hardy egg sacs on a weekly basis, allowing males to find and fertilize them if they are not already fertilized, through the release of gametes, as unfertilized egg sacs will glow faintly with UV light. As before, unfertilized egg sacs will release clone larvae, keeping numbers up and causing the species to be majority female. These larvae, like before, whether clone or not, are born in the hundreds as tiny, vulnerable soft-bodied filter feeders, and only develop 3 slim ‘prime rings’ of chitin upon reaching roughly 1/10th their adult size. The rest of the chitin exoskeleton is developed gradually.