Vinagob
While its ancestor largely fed by waiting for food to fall into its mouth or briefly swimming upwards to catch tiny bits of food, the vinagob is more active. It's one of the largest and most effective filter-feeders of its time, to the point of being an apex predator of sorts in its environment at the time it evolved. It has a diet of largely the very abundant Photosagnia, which often tints its simple, ribbed stomach purple.
It hovers six or seven centimeters above the seafloor in groups of six to eight of its kind, and swims rapidly upward if disturbed. The vinagob prefers deeper areas farther from land in its environment, living in the somewhat dimmer reaches of 100–200 meters down. Clusters of vinagobs at the edge of a continental shelf make a "border" of sorts between the twilight and sunlight zone, and the coastal and deeper waters.
The vinagob's embryo-ejection system of small pores under its lower “fin-pits”, connected to lower disc-shaped air pockets, is now enlarged and connected to its stomach. By filling and emptying the disc-shaped pockets in its body with air and water, it draws in food. While the current it produces is weak, it still gets much more food than its ancestor.
Its enzymes aren’t quite up to task to handle such a high volume of food. Fortunately, it has a mutualistic symbiosis with a strain of cilia detriti, whose cilia and flagella make it possible (if not exactly easy) to swim through its stomach ooze.
The scavenging microbes break down dead, trapped organisms, producing alcohol as a byproduct of its metabolism. Due to its partners’ alcohol production, it not only has some ability to gain nutrients from alcohol, but is also the most resistant to alcohol poisoning of any organism of its time. Cilia detriti can live in such abundance among its ooze as to make visible reddish patches in its stomach.
Between its new ability to gain some nutrition from alcohol and absorbing dissolved organisms, the vinagob is able to grow bigger, faster, and denser than its ancestor. While its ancestor’s body was watery and insubstantial like a jellyfish, the vinagob’s body is like partially-set gelatin, and roughly as nutritious. (if less sugary)
It has the beginnings of specialized reproductive organs. Small, yellowish, easily-overlooked, chickpea-shaped clumps of tissue 700 micrometers in size lie beneath its fin-pits, and produce cloned “embryos” of 80 micrometers in size. A well-fed adult vinagob is very prolific in its reproduction, creating five to six embryos per day. In conditions of low food or stress (such as sensing injury chemicals in the water), it ejects male and female gametes in the water.
It has a weak flavor, something between rotting seaweed, mildew, and rum raisin flavoring.