Serina: Aureate Snurtle (Patreon)

Once a frozen wasteland, the south pole of Serina is now a lush, subtropical rainforest enjoying continuous heavy precipitation and twenty-four hours of sunlight a day in the summer (at the cost of twenty-four hours of darkness in the winter). Enjoying this bounty are the countless organisms which have rafted, flown, or swam to this unspoilt Eden millions of years ago, and now proliferate in countless forms. One such unique organism to the southern continent are the gups, a group of terrestrial gastropods which have developed a true endoskeleton and weight-supporting appendages. Two species of gup landed on the shores of the thawing Serinaustra from the Meridian Islands some twenty million years ago; these began as relatively small, frog-like animals with permeable skin, but in the time since, they have diversified explosively, and now include amongst their numbers very large species which have completely cut ties with the water.

The snurtles are trundling beasts descended from the costal sandlubber, which possessed minute scales of periostracum to help retain moisture. Although the air was reliably humid, its size made evaporation a major concern to the sandlubber due to its much greater surface area compared to smaller gup species. The sandlubber's descendants continued to further develop these scales, which in snurtles have become significantly thickened and enlarged to produce armoured plates for defence beyond just moisture loss. Heavy and ectothermic, they stand little chance of escaping predators by fleeing, so have doubled down on fortifications, studding their hides with heavy scutes, spikes, and wrapping their body in an impregnable armoured carapace. Unlike turtles, their appendages cannot be withdrawn, but are similarly covered in scaly plates that make them extremely tough. Their respiratory openings are large, because these are also the openings from which they give birth, and which contain their auditory sensory membranes, but bony shutters can come down to prevent foreign obstructions or predators exploiting this softer region. As a last resort, a foul, oily spray can be ejected from glands near these openings to ward off any particularly persistent annoyances.

Another reason for the snurtles' evolution to greater sizes was their specialization towards herbivory. Although it's far easier to obtain, vegetation is much more difficult to digest than animal matter, and a larger body allowed them to consume more at once and to contain a larger and more complex gut to more effectively digest what is consumed. A trunk-like proboscis is lined with rows of flattened, grinding teeth, which chew up tough vegetation by muscular undulations before finer mastication by the inner radula. Some snurtle species now grow over one-hundred pounds in weight, the aureate snurtle is one of the largest species, capable of exceeding one-hundred kilograms in weight and over four feet in length in older individuals (although adults average between eighty and ninety kilograms). These are permanent residents of the longdark swamp, easily able to hibernate in a burrow during the winter months when food is scarce. Their large size allows them to push their way through dense vegetation and even shove down low-growing plants for easier feeding. Too slow to hunt, they are nonetheless common scavengers, often swarming in numbers around carcasses, even these already reduced to skeletons (as the bones are a valuable sort of calcium and minerals for building their own shells), and can occasionally consume insects and other small invertebrates to supplement their otherwise vegetarian diet. The spines on the top of their shells can help to push over rocks and fallen logs to unearth grubs, woodlice, and other hidden detritivores. The feelers on the end of their proboscis help them to detect edible roots, fallen fruits, seeds, and worms.

Snurtles are largely silent, and communicate with one another using their colourful antennae, which, along with their eyestalks, can be flicked and pivoted in coordinated motions to convey basic messages. Males compete with one another for females with push-ups, advertising their vigour and strength, but for confrontations unable to be solved by this alone, shoving contests may ensue, bashing each other with the spikes on the front of their shells. Injuries are rare, but sometimes a male may be flipped on his back and become wedged, at which point death may occur incidentally unless he manages to right himself (due to the shell's domed shape, it's unlikely for them to become stuck on a reasonably flat surface). Outside of the fall breeding season, snurtles are otherwise tolerant of one another and do not hold territories. Courtship is initiated with antennae touching between partners, and the animals feeding each other up with their sensitive proboscis to determine physical health, although there is no visible mounting due to the penile organ being long and flexible enough to insert into the female's reproductive vent just by side-to-side positioning. 

Similar to most gups, young are fully independent from birth, although it may take upwards of twenty years to reach sexual maturity (which is reached long before their physical growth slows). Snurtles are buoyant, allowing them to spread across waterways easily, smaller and younger snurtles can simply be carried to new feeding grounds by just allowing the current to carry them down river, ensuring a wide geographical range. Young snurtles often consume the droppings of adult snurtles or other grazing animals to help build their own gut biota, and due to adult snurtles often passing incompletely digested vegetation, which is now made easier for young to digest due to already having been pre-digested.