The Tree Gup and the Spikeray

This guest entry was written and illustrated by Troll Man. 

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Under the seas of Serina, 280 million years post-establishment, snarks now dominate in size and numbers, but their presence beyond this realm is more subdued when tribbets and avians continue to rule. From the shores and estuaries, snarks from the sea gradually infiltrated the freshwater and terrestrial ecosystems, as had occurred amongst gastropods countless times before. On the southern lands of Serinaustra this is more evident, as the amphibious gupgops voyaged from a far off dying land to a far larger land of plenty, but even on the northern continent of Serinarcta, where strange new mollusc life is emerging from the mud. In the millions of years of the warm and moist hothouse era, it was these damp and ectothermic invertebrates which have thrived most, quietly evolving with new innovations and exploiting new niches in the undergrowth... and beyond.

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When snarks rafted to the continent of Serinaustra ten million years ago, they, and many new immigrants to the defrosting lands, discovered a slate wiped clean, with endless food, no competition, and a balmy climate. It was a perfect petri dish from which the small populations that had been lucky enough to be carried by the sea to such prosperity could rapidly grow in number. Dozens became hundreds, hundreds became thousands, thousands became millions. Two founder species, the prismatic gupgop and the speckled gupgop, became over three-hundred species over countless millennia. What fueled their massive diversification was not merely lack of competition, but the variety of habitats which developed alongside them as plant life colonized the surface of Serinaustra. In the evolutionary blink of an eye, forests began carpeting the continent, and following them were so many forest-dwelling animals. To the gups, this was uncharted territory; it had been millions of years since the last snarks had encountered groves of towering vegetation. But if their diversity under the waves had not already proven, snarks are nothing if not willing to adapt.

Clambering amongst the boughs of the fast-growing and highly abundant dancing trees is one of Serina's most peculiar arboreal fauna. Growing only about a foot long, it crawls across the trunks and branches, with back and forth shuffling like a lizard, hugging its flattened body close to the surface and using sticky pad-like fingers on its four appendages to cling to the bark. Its mottled dark and pale body and numerous fleshy lobes make the outline of its body difficult to see while it lies still upon the algae and lichen-encrusted trees, with only its stalked eyes and sensitive feelers twitching to detect food and foe alike. Often it seems nearly as immobile as the tree trunks it sits upon, until it suddenly leaps from branch to branch, darts with swift jolts up and down the canopy in erratic and unpredictable spurts, or launches its projectile proboscis at a small invertebrate that got too close. It was not long ago that this animal's ancestors scurried in the leaf litter far below, but the flitting of flying insects far above was an enticing enough lure for some of them to make a living beyond the undergrowth. This is a gup which has grown slimmer, faster, and more agile to live in a more precarious world.

Although it evolved from a poison ancestor that brightly advertised its toxicity, the tree gup has long since lost this defense. As it ventured in land, it could not longer rely on its diet to provide its toxins, and instead turned to more practical and mundane camouflage to keep itself protected. Like most snarks, it can alter the hues of its skin to darken and lighten itself, or make the spots and stripes stronger or more faded as needed to better match its surroundings. When cornered by a threat, it can also pull out a spectacular last-resort maneuver to deftly dodge its pursuer; the gup peels away, pushing off with its tail and enters a domain previously unknown to mollusc-kind: the air. Spreading its four appendages out, the fleshy lobes provide a crude lifting surface, carrying the gastropod across the sky for a distance of up to two-hundred feet. Its sticky finger pads allow it to immediately latch onto any branch or tree trunk it lands on, but its small size and soft body prevents any chance of serious injury from a botched landing either way.

Tree gups have adapted so well to their new environment that it is theoretically possible for one to never once touch the ground from birth to death. When this rare event does occur, the gup is very quick to find the nearest tree and starts climbing back up; the modifications granted by natural selection to better suit its arboreal life have now rendered it more cumbersome on the forest floor. Even courting and mating occurs in the trees; because they are so well camouflaged,  tree gups must rely on the auditory signals of their mating calls to find one another from a distance, making their ability to pick out the distinct vibrational wavelengths from other sounds in the forest far more attuned. Their feelers have many minute hair-like filaments which allow them to pick out sounds from the air similar to many insects, rather than simply relying on vibrations travelling through the ground. This is an ability that can also mean the difference between life or death when detecting the soft flutter of a wingbeat from an approaching predator tribbat or bird-of-prey homing in.

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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; 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.