Fluterump
Between living in much more open environments than most of its relatives and being more diurnal, camouflage has become all the more useful. Consequently, it has developed a primitive camouflage of maroon spots on near-indigo skin, which appears purplish in some conditions.
At ponds, streams, and swamps, it blends in better than before with water and shores stained purple from Photomniaquatica and Globanitrates, as well as Lithogania in the more brackish parts of Balbasario Swamp. It blends in somewhat with Myserchen, although, with Myserchen’s dependence on growing on other flora, they’re limited to showing up on Shrub Gazebos, making its camouflage less useful.
Fluterumps overlaps with Strontodes in some of their habitats. They co-exist through different activity patterns, different mortality risks and contexts, and slightly different diets.The Fluterump is more consistently active in the day and at sunrise and sunset. Its skin is just slightly thicker than the Strontode's, and the greater mucus production in its air sacs and mouth, as well as slightly bigger water sacs, make it less likely to perish in sunny daytime conditions. Still, they are more prone to drying out than other contemporary fauna, and so prefer shaded areas and seek shelter during midday.
Having slightly bigger water sacs, Fluterumps need to drink less often, putting it at less risk of being eaten by the two species of stream-dwelling Lurkroufos that are their chief predators at time of evolution. However, if spotted or captured, Fluterumps are the favored prey, as their lack of strontium specks makes them less abrasive. Due to spending more time in a agglomeration of foam, it spends less time as a tiny, helpless filter-feeder that can be easily eaten by Lurkroufos. Yet, the eggs are occasionally eaten by generalist Grapplebuns. Fluterumps are also not quite as good at recognizing and avoiding Minidaggers as its relative.
It eats smaller, less crunchy foods than the Strontode; it lacks the ability to wash out noxious chemicals or big or spiky debris from its stomach. In sub-areas where strontium concentrations are low, the Strontode's gizzard-teeth are weaker, inclining it towards less crunchy foods and putting it into more competition with Fluterumps.
Physiology
Oddly enough, despite developing camouflage Fluterump skin is not purple, but an indigo-esque color dotted with maroon spots that practically never matches with its environments. However, the many red dots on bluish skin appears purple from a distance, especially in shaded conditions, at sunrise or sunset, or to predators with poor color vision. Against its few predators at time of evolution, it’s good enough. The red spots and indigo-like background is actually a defect resulting from disease-based physiological stressors, which virtually all Fluterumps get at some point. Fluterumps kept in perfect conditions in captivity never develop the coloration, and instead resemble the Mattebelly.
Its vision, while better than the Mattebelly's, is poor: it's roughly equivalent to a mussel. Unlike Strontodes, Mattebellies smell through their top vents, not their lips, and their sense of smell is poor outside of water.
It has thirty sacs within its body: ten are lung-like, fifteen store water, and five are sinus-like and generate mucus. The mucus sacs have very small amounts of surfactants, homologous with the Fluterump’s gastric surfactants.
Its hindlegs and forelegs are more differentiated, though they remain similar in shape and structure. Only the hind legs have the distinctive "flutes" and are connected to mucus sacs.
It has a basketweave-esque nerve net radiating from its enormous stomach. There are notable masses around its eyes and hind legs. It has no centralized "brain". Rather, responding to visual stimuli is processed by visual ganglia, and most of its reproductive behaviors are controlled by another set of ganglia. The arrangement is somewhat similar to a male mantis being able to mate even if decapitated due to a somewhat decentralized nervous system.
Reproduction
Fluterumps’ reproduction is much more elaborate than before. At sunset or in the evening, it seeks out potential breeding sites, such as a slow-moving stream or a small pond. Its “flutes” then take up water from the water body into its mucus sacs. Nerves around the mucus sacs respond to chemicals of various algae-like organisms, "smelling" whether it's a suitable spawning site. If it determines it’s a suitable spawning site, it flashes its green lights in particular patterns at night. Much like a firefly, it and its relatives use the same colors of lights, but flash them in different sequences to distinguish between each other. (Despite the name, they do not play their “flutes”.)
Once they lure a mate to a suitable spawning site, they roll onto their sides and initiate a spawning sequence of simultaneously releasing gametes while generating a sticky foam from water, mucus, and air. The foam resembles a mass of snot bubbles, and the foam's color comes from trace colorants in the Fluterump's diet and any microbes sucked up its flutes during "smelling". It's generally light green, but can also be purplish. Depending on the conditions, the foam masses can last anywhere from three to five hours before breaking apart.
It has bigger, better-provisioned egg cells than before, and its embryos develop within the foam, which itself contains oxygen. The mucus itself is more nutritious than might be expected for mucus; the embryos extract some nutrients from the mucus as they develop. The embryos start out as bigger and more developed than its ancestor's, and develop still further while in foam. They thus spend less time in a filter-feeding state.
Although its foaming spawn and relatively sophisticated nervous system may seem an overall advantage, it comes at some metabolic cost. It cannot breed as frequently or as prolifically as its ancestor, creating only 230-300 eggs at a time. Its young are also clustered together and immobile for a while and therefore easy pickings for predators that recognize them as food. It’s not a worthwhile trade-off in rainier or shadier environments where the foam is unnecessary protection.
Trivia
Adult microbiota include Melter Detritis, Nitromethanians, and occasionally Pathogen-Eating Detritis, who often end up in its egg-foam and occasionally cause slight staining. It does not have Ribbon-Tailed Detritis, as they are not adapted to freshwater. Like many of its relatives, it has a fairly high tolerance for alcohol, though its tolerance has diminished due to changes in microbiota and diet.
The Fluterumps living near the Balbasario River and Glicker-Squidy Tropical Watershed have slightly different light-flashing patterns and breeding timing. The Balbasario population must distinguish itself from Strontodes, while the Glicker-Squidy Tropcial Watershed population must distinguish itself from Glassbellies. In the Balbasario population, it tends to breed around sunset, not evening. In the Glicker-Squidy Tropical Watershed population, it tends to breed around evening, not later at night. The difference in timing is about thirty minutes, and some timing overlaps still exist. Each population has different flashing patterns, to make themselves more readily distinguishable from local conspecifics. It's only possible for Fluterumps to hybridize before the foam fully settles, making it difficult for Vinarana organisms to fertilize each other's eggs if not mating at the same time. Strontode-Fluterump hybrids occasionally show up, but are often at a survival disadvantage, partly because the two species use such different techniques to avoid predation or discourage predators and having a middle approach is worse than either.
Due to its slightly bigger vent passages, the foaming surfactants of its mucus sacs paralleling lung surfactants, and its air sacs storing and “exhaling” more air, it has the useful spandrel of extracting more oxygen and from drier conditions than its relatives.
It absorbs little oxygen from its skin, as it’s gotten too thick, but it can still passively absorb some oxygen from its mouth and stomach lining.