188 million years: Welcome to the Pangeacene

188 Million Years PE

Ten million years have passed since the Thermocene officially gave way to the Pangeacene, and a look now reveals a world far removed from the hellish landscape of the armageddon. We are now flying over a verdant tropical coastline along the northern coast of the new supercontinent, where tall green trees sway in a light breeze under an open blue sky, green-blue waves crash gently up the shore of a beautiful black sand beach, and a flock of small white birds fly low over the water. The temperature is mild, warm and humid.

Ten million years ago, this coast would have been a sun-scorched wasteland butted against a hot, stagnant sea choked with toxic bacterial sludge and very little else. Today, the global climate has stabilized, with plant life having returned to all corners of the land, and life beginning to return to a healthy state in the sea as photosynthesis returns in abundance, plankton return, and fishes and invertebrates re-diversify from their isolated refuges. The virtually cleaned slate across the moon's ecosystems has now resulted in an explosion of new speciation as life evolved to fill the vacuum left behind by the end of the Thermocene. On the beach, the return of diversity is already obvious, as long-legged birds pick for worms in the sand, large red crabs run back and forth with the tides, picking at flotsam, and shoals of small fishes can be seen circling leisurely in the shallows, every so often startling and scattering as a the shadowy figure of some larger predator comes nearer to the shore, only to turn back as quickly as it appeared when unable to reach their refuge near the beach. At a glance, Serina at the start of the Pangeacene seems to mirror its earliest beginnings at the start of the Hypostecene - but rest assured, this is only a superficial similarity. Alongside such seemingly mundane forms, the moon now supports far more alien creatures unlike anything anyone could have suspected when this all began.

We go along further, following the sea shore, until we come to a tributary spilling gently into the sea out of the forest and turn to follow the stream upriver. It trickles over the dark volcanic sand, between the trunks of broad-leaf trees and single-stalked palm-like specimens that grow twisted and contorted as they reach for the sun. The undergrowth is sparse, consisting of a few types of broad-leaf bushes and sparse grasses with fern-like leaf structure, which become large and dense colonies along the edge of the stream. Colorful songbirds flit between the trees in the patchy sunlight, calling and singing. A colorful lizard - no, a primitive tribbet, colored brightly in blue and orange - flushes from its basking site on an exposed tree branch and vanishes in a hollow crevice in the bark. Every so often, a still pool collects to the side of the stream, where colorful fishes flash their dorsal fins and sidle against one another in competitions of display and transparent shrimp which appear to be made of glass pick delicately at thick growth of hairy green algae. We follow the stream further inland for several miles, but there appears nothing larger or more exotic than small birds. Great numbers of small reptillian tribbets, some with mobile fin-like sails that flash up and down on their backs, can be seen almost everywhere along the ground. Some are plain, others marked boldly with color. Most are found at rest, all but motionless until startled, when they bolt to cover on short sprawled legs, sometimes clambering up the trunks of the trees with little sharply-clawed forelimbs. One particularly small, green one - almost invisible among the leaves until it moves - is seen to be moving inchworm-like along a low branch, climbing in alternate strides its forearms and then pulling up its tail, which ends in a hand-like grasping implement.

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Everywhere one looks, insects in all shapes and sizes scurry and fly through the sandy woodland, along the ground, up the trees, and along the shore of the stream. Some are obviously beetles, but the vast majority visible are ants, still the most specious of all Serinan insects, and experiencing a resurgence in diversity after the Thermocene. Small fly-shaped ones buzz through the air, biting at uncovered skin or drinking from colorful flowers that grow in sunny clearing, while a large wasp form drags some sort of strange brown grub, with two large clawed arms, down into a burrow in the sand. Some large eusocial species still gather leaves from the trees and fern grasses just as their ancestors have for hundreds of millions of years, while others appear to be picking for food washed up by the water, carting away small drowned insects and tree seeds washed from up river in single-file rows. Every so often throughout the forest, we come across a large boll-like structure on the underside of a tree branch - clearly a nest. The forest here, again, is dominated by ant trees, but these are distinct from the earliest wave in that they are not bamboos, but broad-leaved branching plants of sunflower ancestry, which adopted symbiosis with insects initially to compete with the bamboo trees that they've since outlasted. The palm-like plants, conversely, do appear to be grasses, but not bamboos. Close inspection reveals that they don't actually have a single growing bud, as does an Earth palm, but rather a clump of hollow stems and strap-shaped leaves at the end of a tall woody trunk. They do not seem to host any ant colonies of their own, and yet even the leaf-cutters avoid them. This is because they are in fact a new radiation of tree-like assassin grasses. Though their leaves no longer produce beads of herbicidal toxins along their edges, their roots still produce thes agents to help ward off competition from establishing nearby them and they now defend themselves from hungry browsers with a mildly toxic gummy sap that the insects appear to avoid. There are no signs of large herbivores around, suggesting that these plants are still equally unpalatable to larger life.

Small crustaceans colored boldly in varying shades however - some in red and yellow, others powder blue - do scurry along the branches of the grass trees, finding refuge in mats of dead and dry leaves below the green fronds and gathering on dried stems toward the top of the plant on which large green pods have been produced in hanging bunches. Their carapaces are no larger than your pinkie nail, and at first they resemble spiders, with long spindly legs, but they are actually terrestrial crabs. Their brightly armored carapaces glitter in the light, laced with intricate patterns of spines and thorny projections that apparently make them difficult to swallow. As if to prove the point, near the ground a fat brown tribbet lunges upon one only to spit it back out it almost immediately like a hot coal. The spines on the crabs' shell now are tipped with dripping beads of a thick white liquid. Having survived the encounter and taught another predator a lesson it won't forget about what not to eat, it promptly rights itself and returns to the trunk of the tree. Climbing delicately up to through the leaves and along the arching stems, it joins its fellows in feeding on what appear to be the trees' fruits. As they chew into the small pods, they ooze a similar thick, bitter latex to that produced by the crab's spines. In fact, it is the same highly unpalatable alkaloid, which the crab - the only animal apparently interested in working through the sticky sap to feed on the grass tree's seeds - sequesters in its own tissues for defense, to release from specialized glands if attacked by a predator. The crab is most interested in the the tree's seeds, but also consumes the less edible pod in order to reach them, and in this way takes in the chemical agent to which it has developed a high tolerance. The tree produces a crop of seeds only once or twice per year, however, so the crabs not only feed on them but instinctively gather them and store them in underground caches to rely on for the rest of the year. In the process, it forgets a fair percentage which will then sprout and germinate. In this way, the tiny crab has in fact become the sole distributor of the grass tree's seeds, in return for borrowing its defenses, in another unique example of mutualism. Because the tree produces herbicides from its roots that prevent the germination of seeds, its own seedlings could not grow if they simply fell underneath their parent tree.

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The further we follow it inland, the stream gradually bleeds into a larger slow-moving river system choked with grasses and floating vegetation. It is here that we get our first glimpse of something larger, in the form of a large brown mass which dips silently into the water at our approach, leaving only a series of ripples to show it was ever there. We wait several minutes, but nothing further shows itself, and continue moving over the water, keeping a watch on the banks for further clues to what our sighting could have been. If tribbets were commonplace in the stream, they are veritably abundant on the shores of the river, occurring in every shape, color, and form. A large green tribbet with a short ridge along its back clings to a branch hanging low over the water, plucking leaves with strong grinding jaws and hissing threateningly at our approach, while another responds by leaping from its perch and gliding on enormous, oversized gill arches to safety on the far side of the river. Mudwickets - primitive, frog-like ancestors of the tribbet with moist, scaleless hide - can now be seen sitting in great numbers at the waters edge, presumably waiting for some small insect to land nearby so that they can pounce. When disturbed, they plop backward, sideways, and every which way into the water with haphazard flicks of their tails - some squeaking, clicking and popping as they go - leaving only small rings on the water in their place. Working across a half-submerged tree trunk that partially blocked the stream, another strange animal is making its way toward the water. Just three inches long, it is a strange, eyeless grub that moves forward in inchworm-like hops, pulling itself forward with two large clawed arms and then pulling up the rest of its fat, caterpillar-like body. Colored dully in shades of brown, it seems to be an identical but larger version of the grub seen earlier being carried away by the ant, and is in fact not an insect at all, but the larvae of some sort of changeling bird, likely one of the seemingly plain songbirds so numerous in the surrounding forest. Its eyes are slits and its vision poorly-developed - it seems to find its way through smell and touch - it has developed bristles along its body to aid in feeling its surroundings. This individual, however, seems quite lost. It moves quickly down the tree trunk until it comes to the water - surely not where it wants to be. Yet, without missing a step, it leaps right in and proceeds to flap its feeble arms, propelling itself straight across the gap between the log and the opposite shore. Before reaching the other bank, however, it does something even more surprising, and dives beneath the water. Having expanded its diet to include detritus from the pond bottom - or perhaps small aquatic animals - it has become semi-aquatic, retaining its permeable skin for far longer than other larvae and continuing to respire through it. Now able to take oxygen from both air and water so long as it stays moist, its juvenile form strays still further from its eventual adult form and niche.

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Suddenly, a large animal rises from the water and begins to move toward the shore, leaving an obvious trail of ripples in its wake. It now reveals itself to be a shaggy brown bird, approximately the size of a beaver, with small beady eyes, long bristled whiskers, and a dark fleshy snout ending in dozens of tentacle-like tendrils - an obvious descendant of the Kyran water-snuffle, the sole species of soft-bill bird to have survived the armageddon against seemingly all odds though its aquatic adaptations. Largely unaffected by terrestrial interchanges of flora and fauna and able to retreat southwards to safety via newly-formed freshwater rivers that formed as the supercontinent formed, they abandoned their ancestral home just before it became an uninhabitable desert waste. Now far larger than its ancestors and with its snout further specialized, this particular specimen nonetheless appears little changed in niche as searches for prey hidden in the mud along the shore with its nose, shuffling its head rapidly side to side. Never completely exiting the water, after snuffling for a fleeting moment, it turns, grunts feebly, and dives back into the river with a violent pulse of its large webbed feet.

~~~

A ways further along, the river gives way to a wetland, where the current barely flows and solid mats of vegetation cover most of the surface. Large yellow songbirds call aggressively with harsh voices, kya-kya-kya, while clinging vertically to the stalks of reeds and rushes. At first it seems they are guarding hidden females sitting on eggs, but closer inspections reveal something even stranger. Within the clumps of reeds, they have cleared out the centers of stems and dug out shallow pits which have flooded with water. Here, dozens of tiny, black, wiggling, fully aquatic larvae wiggle over the sediment like alien tadpoles, flapping their arms in the water penguin-style to move from spot to spot. Periodically, one of the two yellow adults guarding each nursery pool drop a tidbit of food into the water, a dead insect or a small fish, causing the young to stir and push their way into the group to find a place at the meal. Sinking their tiny jaws into the flesh, they consume it completely in a matter of twenty minutes, at which point either the mother or the father - identically colored yellow with a few black streaks - provide another meal. The parents of these changelings have secondarily adopted an active method to ensure their young are cared for, at least in their first few days. After several weeks, the young will leave their nursery pool and take to a life feeding in the debris at the bottom of the water for the next several years, eventually leaving it to pupate in a riverside burrow to emerge as an adult bird the following spring. Unlike the ninth-year canaries, they will then live as normally long adult lives as any other comparably sized bird, of several years at least, in their mature form giving no indication of their bizarre infancy, as is the usual case for their branch of the avian family tree. In fact, the changelings have become unquestionably the most specious surviving bird group on Serina after the Thermocene due to the extremely adaptable nature of their larval offspring and their ability to produce huge numbers of them with minimal expenditure of energy, and are likely only to diversify further still as the Pangeacene goes on.

Over fallen logs not far from the nesting colonies, a serpentine creature slips into the water, winding over the surface like a snake, revealing itself to be air-breathing and covered in watertight scales - not in fact an eel at all, but a long, legless tribbet. As we move over further and out into the wetland, mudwickets become so abundant as to at times obscure the mud at the shore's edge, gathered in groups from the surrounding forest apparently to breed and to fight over mates with aggressive posturing and flares of their dorsal fins. At one point a fast-moving black blur erupts from the riverbank into the gathering and grabs one of the smaller, plain-colored female mudwickets in its jaws. As the riverbank erupts in panicked hops into the water and weeds by the rest of its kin, the small predator pauses for a moment to glance around. It eyes are tiny, its body sausage-shaped. About the size of a common rat, it's clearly a bird, with a thin, hooked beak adapted to hold tight onto slimy, wiggling prey items but also - it would seem - four limbs on which it scurries along the shore. The hind legs are small, with clearly-differentiated toes, while the forearms are large and paddle-like, ending in large claws. As it retreats into a hole dug into the shoreline, it moves with a frantic, awkward sort of motion much like a baby sea turtle as it scrambles for the sea; it gives distinctly the impression of an animal that is not comfortable, nor built, to live above ground and would would rather be safe in a burrow, but has found the riches to be gleaned along the riverbank too good an opportunity to pass up. As it disappears down the burrow it came, the bumblet - the sole survivor out of all the vivas, likely kept alive by its innate tolerance for low oxygen levels as a burrower and its ability to hide from the harshest weather and radiation underground, and coincidentally the first proper quadruped among all avians - vanishes back into its subterranean refuge.

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We move further inland, until the wetland gradually gives way to a dense swamp, pocketed with islands of broadleaf forest with a rich understory. The sand of the beach is replaced on these isles by a rich, moist leaf litter, through which slimy-skinned eelsnakes slither in search of soft-bodied prey and large cockroach-like crickets are ambushed by predatory mantis-like tree crabs that come down from the canopy to hunt, disguising themselves as clumps of bark or moss. Here we see our first large land animals in the form of a group of completely featherless birds roosting on a large fallen tree near the edge of the swamp. They're rather ugly creatures, colored brown and green like the swamp around them. They are covered in a wrinkled skin dotted with small dry scales and scutes where other birds sport feathered pelage and when disturbed, they crane their necks, revealing wizened, tortoise-like faces and wrinkled dewlaps under their throats. Everything they do is lethargic, and they are reluctant to leave their basking site, where they close their eyes and huddle together, but eventually rise to action when a threat is perceived in the distance. When they rise, they stand just about as tall as a man with their necks outstretched, long muscular arms folded at their sides, ending in a single long hooked claw. Their hind legs are situated toward the back of their bodies and are distinctly sprawled outwards to the sides, with four webbed toes and large claws. They are the secondarily terrestrial descendants of the maritime muck, the second endemic Kyran Islands survivor which, like the water-snuffle, survived by moving into freshwater tributaries as the sea along the islands' south shore was closed off by advancing land and moving southwards as the islands dried out. Their slowed metabolism - allowing them to go long periods of time on little food in harsh times and perhaps even to enter torpor - combined with their efficient respiratory system, meant they were pre-adapted for the harsh low-oxygen conditions of the armageddon event from the start. Though still capable swimmers and preferring swampy environments to call home, these cold-blooded scalebirds now feed primarily on leaves they find out of water, in waterside vegetation and low-hanging tree branches which they can pull down with their long claws. Like their earlier ancestors at the start of Thermocene, small individuals - of which there are several in this group - are capable climbers, spending much time in trees and retreating up into the branches to flee predators, but lacking the two reversed toes on their feet, they are more clumsy and as fully-grown adults generally too large to climb well. Their foliage diet is fairly difficult to digest, and combined with their slow metabolism requires they spend much time resting throughout the day. When pressed by a predator, however, their claws are formidable weapons, and they can become quite aggressive.

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Such behavior is soon witnessed with this group as, after coming to attention, they turn their sights to a shadowy figure moving noisily through the dried leaves higher up on their island. The smaller mucks, one half-grown and one perhaps just a few months old and only 24 inches tall, immediately bolt up the nearest trees with surprising speed, peering down afterwards to keep tabs on the incoming threat, while the remaining adults gather together and splay their arms wide. From the shadows, the threat makes itself visible in a patch of sunlight: a large tribbethere is approaching. The adult mucks respond by lowering their necks and growling and honking defensively - but will the threat display be enough?

Tribbetheres produced a brief variety of large carnivores right at the start of the Thermocene-Pangeacene boundary, but only survived the end of the Thermocene through a single small, burrow-digging species that was able to weather several million years of harsh conditions - high radiation and extreme temperatures - underground, coming up at night to hunt insects and small animals. The first large forms did not survive, but as soon as conditions improved, the sole survivor was among the first predators to respond to the ecological vacuum. Today, several distinct types have already re-diversified, as the tribbethere lineage recovers from its close call with extinction. Among the most notable are a new group of dog-like heterodont carnivores, with long cutting fangs in their upper jaws, which prey on large animals. Their legs are long and held under the body and allow them to run at high speeds - indeed, their hunting method is to run down their prey. The hind leg, in particular, is muscular and able to launch the animal forward allow it to deliver a killing bite to the neck with the large jaws. Unlike earlier tribbets, which fed on prey they could swallow whole or easily dismember by tearing, these new predators often bring down animals of a far greater size and have developed additional serrated cutting teeth in the jaw, more advanced than the needle-like structures of earlier tribbets and better able to glean mouthfuls of meat from larger carcasses.

In this case, though, the predator is outmatched - he could possibly manage one of the mucks, but there are half a dozen, and they spotted him so early on he stands no chance of ambush. As the scale-birds keep their eyes on him and continue to make a raucous he skirts around the group, trotting lightly on three lanky legs, and continues on along the water's edge before leaping over a short gap between islands. He almost makes the jump, landing a few feet shy of dry land in the water. After reaching the bank, he stretches his legs out and shakes off his paws one by one, just as a cat responds to stepping in a wet patch with visible disgust. He may have been a fish once, but it has been a long time since he has had a fondness for getting his feet wet. And to make matters worse, he will still have to find a meal elsewhere.

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Even in this small area of a few miles, it is clear to see that the global biosphere is recovering from its narrow miss with complete annihilation at the end of the Thermocene. Though the lucky few colonists have already spread out and diversified substantially in the past ten million years, however, it will be another forty million before biodiversity returns to its former levels. The Thermocene-Pangeacene boundary resulted in mass extinctions not only for birds, but fishes, crustaceans, and even insects. Not only have serestriders, tyrant serins, serilopes, whalebirds, and trunksnouts gone, but the vast majority of all sea life. Bivalves and molluscs survived almost exclusively in freshwater environments, the hot and highly acidic seas of the armageddon having become unsuited to their survival - and it will take many millions of years more to replace the lost reef-building hydras. Gone are the giant sea slugs, and nearly gone were even the marine fish - only the smallest forms survived in isolated oxygenated pockets near the surface, with the few surviving freshwater species later spreading out and replacing many of those which died out. Among insects, the end of the Thermocene completely wiped out the florgusts, arguably the most specialized of all Serina's crickets and during the Thermocene one of the most diverse of all insect orders, which had developed a caterpillar-like larval state in convergence to the changelings, and very much like the butterflies they'd come to resemble extremely closely. Other pollinators such as honey ants and vespers were also extremely affected by the loss of their host plants with the spread of desertification, dying when they ran out of food. Many of the plants dependent on them in fact out-lived them in the form of dormant roots and seeds, however, which burst into life when conditions became more favorable again only to find now they had no pollinators. Many such plants thus died out slowly over the years after the extinction event if they could not quickly adopt a new method to reproduce. The few plants which were still able to spread, such as wind-distributed grasses and the myrmecophytes which utilized ants to distribute their seeds - a group which came through the extinction relatively well - took full advantage and spread rapidly across the moon, over far wider ranges than they had before the armageddon event. As soon as the equator was no longer a barrier to the spread of life, wind-blown seeds crossed the seas on air currents, recolonizing barren northern lands.

It is so that even though a functioning global ecosystem has already reappeared, it is considerably less diverse and more homogeneous than before the armageddon, with many similar plants and animals descended from the lucky south pole survivor pool found across the planet. Over time, new specialists will evolve, new groups will form and old ones will be outcompeted. New habitats will be formed and new niches will be exploited. The armageddon event, to some extent, is like a second genesis for Serina, as a whole new group of colonists are now spreading out and evolving new forms suited to their large and bountiful world.