Serina: Creeping Spikeray (Patreon)

At the end of the ice age, snarks proliferated in the ecological vacuum of this catastrophic upheaval and spread to every corner of the globe. In the seas, they conquered ever niche from tiny worm-like bottom feeders to the most massive predators, while the gupgops rafted from distant lands to the southern continent of Serinaustra, where they rapidly radiated into dozens of species. However, on the northern continent of Serinarcta, their presence inland is limited to a relative handful of freshwater spikerays and the myriad of parasitic species that managed to hitch a ride on the ever-growing number of megafauna both aquatic and terrestrial. This absence is largely explained by the fact Serinarcta's life was the least affected by the rapid global warming than the rest of the world, and so snarks did not get a chance to exploit as many niches here as elsewhere. However, this does not mean that they have not managed to evolve and adapt here; already, remarkable adaptational characteristics are developing among those species that have penetrated into the continent, including the first tentative steps to a world outside the water.

In this time in Serina’s history, the continents are dominated by hundreds of thousands of square miles of wetlands and much of the land is crisscrossed by rivers and lakes. Many animals have evolved that are able to exploit both land and water habitats, the thorngrazers, the skuorcs, the trunkos, the sawjaws, and many others; and one of these amongst them is a small unassuming gastropod. This is one of several freshwater spikeray species that inhabit Serinarcta and in terms of size, appearance, and diet, it is unremarkable. It is small, weighing less than eight pounds, its skin has a typically cryptic patterning for camouflage from both prey and predator, and, like most spikerays, feeds mostly on smaller, slow-moving animals. What makes it remarkable is one thing that it does with far more regularity than any other spikeray species, something shared only with snarks on the other end of the world: it spends most of its time out of the water, on land.

The step from water to land is not as revolutionary as it may seem, because, after all, gastropods became terrestrial on Earth at least ten times independently. Living in a world where ponds and streams are often separated by land, spikerays of Serinarctan have already become adapted to using their muscular fins to drag themselves short distances on land, once used for pushing along the seabed in their marine benthic ancestors, and in an unpredictable world where their watery habitat could drain or become stagnant at any time, they had begun supplementing their respiration with oxygen straight from the air. The creeping spikeray is however, the first species of spikeray which has come to the realization that being able to abandon the water and crawl about on land freely and frequently allowed it to spread and colonize new habitats and find new food sources far more quickly than its relatives. Rows of barb-like spines along the edge of its fins give it one crucial advantage, the ability to cling to dry surfaces and provide traction while heaving itself out of the water so that it can actually push itself about rather than simply shuffling; the precursors of claws.

Its large, bony head plate always it to shove through tangles of vegetation, both on land and underwater, and the hooked points at the ends provide additional grip when climbing up steeper embankments. If absolutely necessary, the creeping spikeray is even able to make short leaps by pushing off its tail, although these hops are clumsy and strenuous. Like most spikerays, it relies on its venomous stinger for defence from predators; however, unlike most spikerays, in this species is part of a radiation in which both sexes have stingers. This likely occurred due to an intersexual mutation in a distant ancestor as they were faced with more intelligent predators with highly attuned visual senses capable of picking out the minute differences between male and female snarks, making it no longer consistently viable for females to merely attempt to resemble the more well-defended males. 

A perpetually warm and humid climate where rainstorms lash the land on an almost daily basis allows the spikerays to remain out of the water for days at a time, as there is very little risk of desiccation, although they are quick to escape underwater when threatened, where it can move far more quickly and gracefully. But now that the species has become more adapted for its terrestrial existence, it can no longer remain submerged indefinitely; its respiratory system now struggles to pull oxygen from the water, and it will drown within an hour or two if unable to surface. Newborns are more aquatic than adults, as it takes several weeks for their air-breathing lungs to develop and their fins to grow strong enough to pull their body weight around.

Creeping spikerays raise their young within communal natal pools free of aquatic hunters, where numerous parents can assist one another in watching for predators. Spikerays will defend and feed their litters for three to four weeks, as they will grow rapidly on their parents' nutrient-enriched mucus and quickly learn to hunt food for themselves, usually becoming independent within the span of a month. Having up to fifty young at once, mortality at this stage is extremely high, but their advantage is the ability to disperse widely, quickly, and indiscriminately, disappearing into damp leaf litter or under a sunken rock all the same, able to hunt insects and other invertebrates on land, or fish and small crustaceans underwater. In the span of a scarce few millennia, the species has spread throughout almost the entirety of the the northern continent; although they got off to a bit of a slow start, it seems almost inevitable now that these scrappy little molluscs will be the start of yet another major success story of the snarks during the hothouse era.