Description
1/19/19 - The map has been updated with more detail!
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Almost exactly five years ago today, I posted the original Sheatheria project. It was a world where I could go wild, designing any sort of crazy wildlife imaginable. The initial setting was an impossible world, with equatorial ice caps and bizarre climate conditions, and quite a lot that broke the laws of physics. It didn't feature much about evolution at first. The project lasted several years and went through a lot of revision until I felt it was such a mess that it could not be continued. Several attempts were made later to revive it, but I was unhappy with them all. I decided Sheatheria needed a major overhaul, and it briefly became "Oxymor", but again I felt myself re-imagining the world, thinking of ways to revitalize the concepts while staying true to the original project. Today I finally bring you what will be the final incarnation of this magnificent world of mine. Under a new name and a new premise, old characters will return in spicy new settings and meet entirely new players to hopefully bring the fun of the first Sheatheria to a new generation of speccers. The official successor to Sheatheria has arrived. New setting, new name, all new art, and a new take on a world familiar yet fantastical.
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With so many worlds in the universe, countless planets all spinning endlessly around countless suns, at least a fraction are almost certain to bear life. To think the Earth is alone in the universe is statistically improbable. Presumably if life has occurred elsewhere then most of the organisms found across the cosmos would not closely resemble us or the rest of our tree of life. Forged in different circumstance and perhaps from different structure, most extraterrestrial organisms would probably come across to us as utterly alien. Yet, if the universe is almost limitless, and within it can be found equally abundant worlds for life to evolve, it is entirely possible that through similar circumstance the natural process of evolution - the gradual changing of that life over time by tiny, incremental, beneficial genetic mutations - at least one could have produced creatures - plants and animals - very much like Earth's. The odds of such a parallel course of history, of course, would be very small, but in the vastness of all existence, even the slightest possibility can become reality.
Imagine, if you will, a second "Earth" in another solar system almost identical to ours. This planet is slightly smaller and quite a bit warmer and wetter than the modern Earth. It's topography is different, with unfamiliar continents and strange and at times almost exaggerated ecosystems, but at a glance the two worlds differ only in superficial details. It sits in our place relative to the sun and so is warm and habitable - so much so in fact that it would be classed as superhabitable, supporting an even wider degree of biodiversity as a result of its milder climate and a more complex terrain. Green jungles and bright blue oceans cover almost the entire planet, and across its surface life is in abundance. Beautiful and striking wildlife stride, stalk, climb, swim and fly across it from pole to pole, but though strange and foreign, the flora nor the fauna look extraterrestrial, but rather like life from our world that had long ago become isolated in some far off land, and given their degree of convergent evolution it is from this perspective that they will be viewed - it is not the purpose of this exposition to describe life in a truly alien world. No, life on this planet, forged as it was in similar circumstance, shares every fundamental of biochemistry with the Earth's and much of it has traveled down similar enough lines so that a visitor there would be able to broadly identify most creatures they might come across. - but this hardly means that the local wildlife is plain. The flora here is green and flowers rival ours in beauty, it is true, and yes, the animals, at least the majority, have just two eyes. Fish, or things very much like them, swim in the waters. Mammals, with their characteristic, often expressive ears, their furry coats and milk to nourish their young ones, are among the dominant fauna, but here we begin to notice very different trends. Instead of four legs, most of them stride around on just two, while those which don't sport unexpected bright colors across their bodies and strange nasal appendages. There are birds here too, all of them with familiar beaked jaws and hard-shelled eggs which they sit upon to hatch their offspring and many that can fly... but there are just as many that walk on four legs with no wings to speak of and not even the winged among them have feathers, just a hairy coat. Flowers grow up from the greenery in a splendid display of color to attract insects to help them reproduce, though when what looks at first to be a small butterfly with long antennae upon its head alights on the blossom, it reveals itself to be a vertebrate, but with too many legs - about eight in all counting its wings, which are formed more like a bird's than any insect. It looks out and around itself with wide staring eyes like those of a frog, and the long clawed toes of a lizard let it grip the stem of its perch to drink by uncoiling a long tongue from between four mobile jaws on its head just underneath its eyes.
The life on this world, as becomes apparent on closer examination, is not an exact replication of Earth's. Somewhere along the line, here or there, deviations occurred from a parallel origin and these changes have only built further upon each other. This is a world with broadly similar end results, but a very different natural history, where among other things there are no arthropods and where instead almost everything on land, bar the lowliest worms and microbes, has a backbone. Endemic bugs thus function more like tetrapods and must maintain a warm-blooded metabolism to fly, and relatives freed from the restrictions of an exoskeleton can grow to enormous size and scale. In this tree of life only the vertebrate animals have made major strides on land, doing so in two waves: the bugs, more specifically known as the polyarths (meaning many limbs - most forms have at least six), which evolved from a many-legged worm-like animal that crawled ashore 550 million years ago, and the tetrapods, four-legged animals which there just as here evolved from something like a lobe-finned fish. Just how that fish's descendants would evolve over time, however, would not be the same as our ancient aquatic grandparent. On this planet the native birds sit alongside the local mammals as each other's closest of kin, allied as a unique group of warm-blooded vertebrates called hematotherms (meaning warm-blooded) in a world where dinosaurs and synapsids never existed but instead both groups originated from a salamander-like ancestor, part of a lineage which radiated after that first fish left the seas some 425 million years ago. More distantly related to the hematotherms, a third native tetrapod group descended from the early salamander lifeforms are the ducoranans (meaning leading, or running, frogs, both names applicable to these agile creatures which far outpace any Earth amphibian), today represented by a wide variety of warm-blooded animals most often resembling frogs stretched and scrambled into the forms and niches of widely disparate animals, from birds to monkeys. They are live-bearing, but otherwise combine normally avian and mammal behaviors with distinct quirks all their own.
In this version of natural history the living tetrapods are represented majorly by the warm blooded, active animals with very few surviving ectotherms. This is a world without any close equivalent to a lizard, at least so far as appearance. While endothermy has evolved as well in the varied branches of the polyarths, much of their diversity still includes cold-blooded forms that fill a very wide range of niches on Earth occupied by insects, fishes, molluscs - and reptiles, which have monopolized these forms on land since before the tetrapods had evolved. Indeed, no native tetrapod has ever evolved a fully scaly skin; their wet, tropical planet instead favored keeping the ancestral condition of a bare glandular one, from which hair or something very close has twice evolved in different branches for purpose of insulation, and from one of those hairs subsequently something arose approaching feathered plumage - but from the mammal branch of the tree, not the avian.
Though this is an Earth-like planet, just as the native life has not totally evolved along Earth lines despite a similar ancestry, neither are environmental conditions especially alike. Unlike the more balanced Earth, with its wide variety of different climates, this is a greenhouse planet - a desertless, nearly iceless world of extreme moisture and very little aridity - heavy rainfall over almost all of the planet leads to incredible erosion, and where rain is not constant, seasonal flooding can turn forest to sea in a matter of days. Most of the world's land is split across two large continents, Aenvarna which is broadly equatorial and Andromere which is polar, and the two have been moving apart north and south since they split around 60 million years ago, when the life upon each became largely isolated from one another; even so, a string of islands still serve to allow some daring creatures to travel between them. There are few mountain ranges on the planet, those remaining having been heavily eroded, and most of the world is at or below sea level. Most of the global ocean is very deep, but shallow coastal ridges worldwide and a submerged shallow water "continent" between Aenvarna and Andromere known as the Sea of Tranquility support highly productive ecosystems founded on reefs and aquatic vegetation.
Due to its wet climate, we will call this world Pluvimundus, the world of rain. A beacon of biodiversity in the cosmos, untouched by man, life thrives in the unique environments it supports.