228 Million Years: A Recovered World

228 Million Years Post-Establishment

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The Land

All of Serina's eight major landmasses have now come together to form a single supercontinent. South Anciska, Wahlteria, Stehvlandea and Karii have completely joined around the Kyran Islands. Most interior seaways between the continents have drained away completely, with several large freshwater lakes having developed in the last remnants where they once occurred. The last seaways remaining occur between Striata and Wahlteria, but these two have begun to recede. One stretch of sea cuts eastward about halfway to the east coast, while another still exists opposite to it connecting to the east coast. North Anciska has collided with the supercontinent over the past forty million years, the full extent of its attachment still obscured by the aforementioned eastern seaway which sits right at its attachment junction, flooding all but a thin land bridge between the two continental plates. Polar Anciska has also recently collided as it moved in a north and eastward clockwise arc, now attaching to Striata on the opposite coast from its long-lost more southerly counterparts, which began over 200 million years ago as a single continent in Serina's west. Borea has moved west but retained a polar location, its islands having weathered substantially more over the past eons to a fraction of their former size.

The global climate remains relatively mild, but is cooler than through most of the Thermocene, particularly toward the southern hemisphere. Currently there are no permanent ice caps, but glacial periods have occurred several times in the last several million years during which they have formed only to recede again. Seasonal snowfall occurs in polar regions, though the south pole is extremely dry, with extremely limited precipitation. Equatorial regions, however, are hot and humid towards the coasts, with rainforest common toward the equator. The climate of the lower portion of the supercontinent, however, is dry and arid, with an enormous interior desert taking up much of the southern hemisphere. Large seasonal grasslands border the dry interior, where temperatures reach extremes of both heat and cold. Here plant life is limited and in some regions virtually absent, with the vast majority of biodiversity in this era occurring along the outer edges of the continent in the savannahs and broadleaf forests toward the poles and in the northern hemisphere. Coastal regions near the south pole are less arid than more inland locales and are able to support a greater diversity of plant life, but harsh temperatures limit these environments largely to taiga and tundra ecosystems, absent in the milder north. Moving towards the equator, the coastal forest belt expands into large tracts of temperate broadleaf forest, with the east coast of the supercontinent in particular experiencing extremes of rainfall which combined with relatively mild winters and long growing season have allowed for the evolution of some of the tallest trees ever to exist. Moving north along the east coast, the climate stays equally wet but becomes tropical, forming a huge continuous tract of tropical forest on the moon from coast to coast along the equator, a hub for biodiversity. Some parts of this forest is true rainforest, while in others a seasonal tropical woodland biome predominately, where trees may lose their leaves in the heat of summer to escape drought, returning to life in the rainy season. All of the northern landmasses are dominated by temperate woodland and grasslands with clearly distinguished cool winter and hot or mild summers.

It is the southern interior desert which experiences Serina's most extreme temperatures in this era, both of hot and cold; highs approaching 120 degrees Fahrenheit and winter lows of -30 degrees are not unusual. Conditions in the north are conversely much more mild, with winter temperatures even on the northernmost land of Borea barely reaching 0 degrees Fahrenheit, but even this far-isolated land sees high summer temperatures and lush forests fueled by high rainfall, kept warmer by a lower elevation than the south pole and warm oceanic currents.

The Life

Life on the new supercontinent is now diverse and varied. Tribbetheres and multiple lineages of birds have simultaneously given rise to charismatic megafauna, but there are general trends in regards to which groups do what most effectively. Carnivorous tribbetheres have experienced a boom in diversity and have proven successful broadening their diets into both omnivorous and predominately herbivorous leanings, though as predators they are most significant, filling these niches across the supercontinent. More basal species give rise to a highly successful group of rodent analogues, which utilize a unique mortar and pestle-like jaw design made possible by their specialized extensible jaws to grind open nuts and seeds. A third group of primitive tribbetheres become arboreal insectivores, becoming the first group outside introduced insects and canaries to develop powered flight as they leap and glide to catch prey with extended patagia of skin on their arms.

Among birds, the cold-blooded or mesothermic mucks have been largely relegated toward small or specialized niches after a short period of experimentation as megafauna at the start of the era, but survive in larger forms in the tropics. Among all surviving birds, snuffles initially seemed to be one of the best suited to terrestrial radiation if the history of similar animals on the Kyran Islands were any indication, but likely owing to their aquatic specialty, have not produced large terrestrial species or expanded far out of their mainly carnivorous diets, though are nonetheless very widespread and successful in riparian environments where they continue on as they have for so long in primitive forms. Instead, the big herbivore niches among birds are filled predominately by a group that would likely not be anticipated: the highly specialized changelings.

Changelings, or metamorph birds, remain the most successful of all Pangeacene birds by numbers of species and have displaced many other bird groups to make following their extinction at the Thermocene-Pangeacene boundary, from which they were likely spared as a result of their more adaptable juvenile period and higher potential reproductive output. Some of the last "primitive" flying birds are members of the ancient waterfowl-like group descended from the Hypostecene galliwalts, which now lived over 200 million years ago, and a clade of seabirds which descend from a single gull-like survivor species. Perhaps due to their relatively specialized lifestyles, these particular groups are not yet in severe decline and make up roughly 10% of modern flighted bird diversity. Another 20% is made up of sparrowgulls, the least derived-looking living bird group which closely resemble ancestral passerines, but which have ancestors that were generalist, gull-like seabirds; these birds continue to find success despite a living fossil appearance due to increasingly intelligent behavior. The other 70% of flying birds, however, are metamorphs which have moved into a wide variety of niches in adulthood, including seed-eating, pollinating, and even predatory niches which were once filled by more primitive birds. Changelings have further monopolized niches from wholly unrelated animal groups including many beetles and certain fishes in their immature life stages, which some groups having even become neotenic and now able to mate without ever maturing into a flying adult or maturing at an intermediate stage. A side-effect of adapting as larvae which has greatly aided them in radiating into a broader range of niches than was possible for ancestral bird groups was the ability to move along using their underdeveloped wings in their juvenile life stages. This allowed for the evolution of the necessary musculature to retain the forearms as walking limbs in adults, rather than to re-purpose them as wings. The first such birds retained wing claws to climb and grip, then to support weight. Members of such intermediate stages which were able to put weight on their arms while still retaining flight specializations were able to develop a quadrupedal launch similar to that of pterosaurs, greatly increasing their potential size while still able to fly far beyond what was possible in a biped.

In some other groups the walking limbs eventually became wholly useless as wings, losing their patagia and specialized arrangement of flight feathers and becoming longer, to brachiate, climb, or even run on the open plains. These quadrupedal specialists, as they became larger than was ideally suited to metamorphosis (at such great sizes, the process of development from one form to the next would be too ungainly and prolonged), experienced a reversion of their prolonged larval life stage. Their solution, having already lost the need for a calcified eggshell, was to hatch their young internally and allow them to mature inside the parent, nourished by a placenta-like structure, through a hastened, vestigial larval stage, then a lengthy period of growth and development from a superficially primitive bird-like fetus into whatever increasingly specialized form it would have as an adult. The young would then be born alive in varying stages of development depending on their niche - fast-running plains herbivores would retain their young longer, so that they could run from predators shortly after birth, like ungulates, while more primitive forms would need to raise their young for more prolonged periods in sheltered locations as they developed, such as occurs in Earth primates, rodents, or carnivores. Modern quadrupedal changelings were not the first birds to respond to the ecological vacuum after the extinction event and radiate as large herbivores - the very first were in fact large and ratite-like primitive waterfowl, which declined only in recent time as a direct result of their competition. Today, however, among birds changelings dominate such niches almost exclusively, the only other birds to also still have some surviving large, non-flying herbivorous forms being the mucks, and with these in noticeable decline versus their former diversity.

Among flightless birds, however, there are more generalized and carnivorous survivors, not so much in the form of the large "terror-birds" which dominated Serina's ecosystems for so long, but especially in smaller forms and in aquatic and riparian environments. Snuffles - coincidentally, one of just three bird lineages left which still incubate hard-shelled eggs in nests (along with surviving waterfowl and seabirds) - are widespread but primitive; bumblets have also become cosmopolitan, and furthermore have moved into several new niches. In several respects, these ancestral burrowers have much in common with advanced changelings: both are capable of walking on all four legs and retain their young in their bodies, not laying external eggs. Bumblets - even though warm-blooded and active - have sprawled forearms, however, and are incapable of an upright gait; they are thus slower and more ungainly. Their reproduction is simpler as well, with underdeveloped chicks being born immediately after hatching from soft-shelled eggs inside the mother's womb and requiring a prolonged period of care, and works much more effectively for smaller animals which dwell in burrows for protection, which is what all bumblets still do at least to breed. The ancestral burrowing survivor species has by now given rise to a number of larger forms which spend more of their time above ground, including species that counteract their handicaps in agility by being armored or conversely, covered in quills that dissuade attacks by predators and have expanded from a carnivorous diet to an omnivorous one. Others become more aquatic and begin to feed more in the water, the start of such behavior already shown in species from forty million years ago. Their ability to flood their oviducts with oxygen increases, allowing pregnant females to dive while retaining their soft-shelled eggs until they hatch. Oceanic species and waterside ambush predators have resulted, but they are inhibited from becoming totally aquatic like the whalebirds of times gone by the underdeveloped state of their chicks - they return to land to give birth and tend their young.

Changelings, however, do not have any such restrictions, and produce large aquatic forms both as derived adults and neotenic larvae. Even tribbets, which only left the water for the first time comparably recently, return to aquatic niches multiple times, both from more reptillian and tribbetherian ancestors.

Invertebrates evolved just as quickly as their larger counterparts to their post-extinction world. Ants are thriving with the second wave of ant forests, with levels of diversity unseen since the Cryocene. Land crabs begin to displace many crickets and arachnids, becoming increasingly abundant in drier terrestrial environments. Those pollinating crickets, the florgusts may be gone, but their line has not completely terminated; they have left behind descendants in the form of predatory, neotenic centipede-like forms which descend from a caterpillar-like larvae that has ceased to molt into a flying adult. To replace their lost adult niche, a group of colorful beetles with sucking mouth-parts and showy wings arise to take advantage of the vacancy, but they have competition again from the changelings, one group of which has become exceedingly small in adulthood, producing the smallest birds ever to live, some of which specialize to feed on nectar. One lineage further specializes into insect-like eusocial colonies, where infertile adult workers raise the offspring of a single breeding queen which never fully matures and exists solely as a blind, featherless egg-producing machine with a disconcerting amalgam of fetal avian and grub-like attributes. Other more primitive changelings became fly-like, laying their eggs opportunistically in carcasses or open wounds rather than producing larders in nests. It was not a great leap from there to true parasitism, and forms by this period exist which lay their eggs in the bodies of other animals and spend their larval periods as parasites, feeding from the flesh of their hosts before maturing into adult birds.

Some changelings whose young mature in water have been able to cut their ties to the land completely, and may never land after fledging. Like swifts, they are agile flyers who pursue a nomadic lifestyle of chasing insects on the wing. Unlike swifts which have to land to rear their eggs, though, these birds need devote no more time to parenthood than skimming over the surface of a pool or river and releasing a sticky mass of tiny eggs into the water, to mature entirely on their own. Breeding, feeding, drinking - via a similar skimming motion - and even sleeping on the wing, in adulthood they become the most truly air-born of all creatures.

At sea, extremely derived neotenic, aquatic changeling birds crawl and squirm, feeding on detritus or ambushing prey on the sea bottom. One group which evolved to develop its eyes early on now even competes directly with fishes, having become a highly mobile, agile swimmer propelled by a muscular streamlined body and fluked tail. Living in a world of fishes which - as descendants of guppies and swordtails - predominately give live birth, it has ended up being a bird which reproduces by spawning thousands of tiny eggs at sea. The "birds" then spend their first few months floating as zooplankton, before growing large enough to form free-swimming shoals. They are perhaps the most extreme example of regression in all the animal kingdom; many land-animals, descended from fishes, return to the sea. Some even become secondarily fish-like in form, but none come close to the nearly perfect replication of their ancestors as can be seen in such changelings.

Reefs have recovered in a stable sea, this time formed by the blind, tentacle-mouthed, filter-feeding descendants of freshwater snails.

Jellyfish experienced a boom in the harsh seas of the Thermocene-Pangeacene boundary, one of the only groups to come through the event relatively well. One of the most successful groups diverged at this time are tiny, highly reduced photosynthetic box jellies which have lost completely their arms, eyes, and feeding organs. They now float in the open seas across the world, from poles to tropical coastal waters, living on sunlight and nutrients they absorb passively from the water alone and adhering to one another in first chains, then clumps which come eventually to form massive mats over the surface to provide welcome food and refuge to fishes and other aquatic life in waters too deep for conventional reefs to develop.

Bamboo nearly became extinct at the Thermocene-Pangeacene boundary after a long decline, but survives as a single lineage, the completely aquatic sea bamboos. Bangroove forests survived right up until the middle of the Thermocene-Pangeacene boundary, but eventually succumbed to the extreme conditions affecting the equatorial regions where they prospered. Sunflowers are now the most dominant forest-producing plant group. Pineflower trees did not make it, however. They died at the boundary like so many other groups, their temperate biomes shrinking up the faces of mountains until they could no longer take the rising heat and perished. Their relatives, the hardy cactus-like shrubs and bushes, did make it through the extinction event, some of the only plants which managed to survive the extremes of heat and cold away from the south pole and among the first to spread out when conditions began to recover only to be mostly out-competed by forests along coastal regions and in the north as soon as temperatures cooled. Today they still thrive throughout the dry interior, where little else can. Grasses continue to dominate the intermediate regions, too dry for forests but too wet to become deserts. Sea bamboo forms dense underwater meadows in shallow coastal waters across the world, home to myriad specialized aquatic herbivores and providing refuge to countless small fishes and invertebrates.

Assassin grasses have died out in their ancestral niche completely and largely fallen into obscurity, but have given rise to a group of tree-like plants which still hold on in a variety of harsh climates worldwide, where sunflower trees don't do well, including along the salty shore of the ocean, the borders of deserts, and cold mountain slopes. They are aided by herbicides produced in their roots which prevent competitors from growing nearby them, but this also leaves them highly dependent on animal dispersers for their seeds to find new places to take root. Coastal forms use crabs, and it is surely because of this association that at least one group of land crabs began moving so rapidly inland, as they followed their host trees. The assassin grass tree has declined considerably in the last twenty million years, however, coincidentally following the time frame over which the specialized seed-eating tribbetheres evolved. It is likely that the trees did not evolve with any seed-eating predators before this time, with the exception of the crabs that dispersed their seeds by burying them in shallow caches. The tribbetheres grind them up and eat them, and any they stash may be buried at deeper depths than the tree has adapted to be able to sprout from, for it sprouts from a tiny seed and cannot at that time reach the surface from depths of more than an inch or two. It has thus since been pushed to the extreme edges of the environment, where tribbetheres are less abundant, but also where - except at the sea coast - its mutualistic crabs cannot survive. Interestingly, though, the crabs have adapted apparently without issue to new diets and remain abundant in inland forests long since abandoned by their former host as a diverse group of small arboreal herbivores.

Serina has never been a more alien place than it has become 40 million years into the Pangeacene.