5 million years ago
In this epoch of Earth’s history, Antarctica is mostly encased in ice. However, life holds on: forests of Nothofagus grow even in the central mountains, and a lush tundra of grass, moss, cushion plants and sedges forms during the summer months, buried under snow during winter months.
Feeding on them, all year long, are the shagrats, sheep-sized mammals covered in extensive woolly fur. These herds of polar foragers are the last representatives of an ancient clade known as Gondwanatheria, an offshoot of the multituberculates that once spread across the southern continents. A particular group of gondwanatherians, the sudamericids, were the first grass-eating mammals, and were more than capable of adapting to the extreme cold, having accompanied Antarctica’s cooling since the Mesozoic.
Elsewhere, the last south american gondwanatherians have just perished, grazing inhabitants of the Pampas such as Patagonia peregrina. But out here, the shagrat has endured longer, whatever competing mammal groups nowhere near as efficient grazers. Now, these herds travel alone across the frozen wilderness, their numbers comparable to those of Lystrosaurus in this very same continent during the early Triassic.
Unable to hibernate, the shagrats have instead invested in long-distance traveling. Their limbs are fully erect and digitigrade; while they are not cursorial mammals, they are endurant and can travel across the tundra always on the move. Their forelimbs bear strong claws, allow them to dig through snow whenever necessary. Like their ancestors, their hypsodont molars allow them to grind through the toughest grass, but in the absence of competitors they also have access to softer vegetation.
In winter months, the herds travel across the mountains, seeking shelter from the winds and to make use of the lush valleys, their vegetation now preserved by the snow. The herds spread thin across this valley system, to avoid competition. This tactic is averse to that of polar mammals in the arctic, but shagrats can afford to do it because there is only one predator capable of tackling adults.
Conveniently, said predator emerges from the snow, breaking its camouflage to attack a lone shagrat. The struggle is long, as the herbivore still has powerful legs and a painful bite, but a pair of saber-teeth puncture the throat, and all that fighting turns into a pointless waste of blood. Now inert, the corpse is dragged away, uphill.
The culprit was the snowstalker, the last terrestrial mammalian carnivore in the continent. This animal is an australidelphian marsupial, it’s remote ancestors small mammals akin to the Monito del Monte. As Antarctica froze, its ancestors moved from the trees to the tundra and became carnivores, taking the niches emptied by the extinction of other southern metatherians, from opossums to sparassodonts. Now, it is all that remains, hunting the last remain terrestrial prey, and the occasional seabird.
Like its distant thylacosmid and deltatheroidean cousins, it developed long canines to cope with prey as proportionally large as the shagrat. As this is a recent development — it’s been only three million years since its ancestors shifted from small, kowari-like insectivores to tasmanian devil-sized macropredators — the snout has not been significantly modified, being rather dog-like. The bony tail has reduced in size, leaving instead a hanging sack of fat reserves.
Which in this individual is rather small.
As it drags the corpse to a cave, we find out why: two cubs, which have left the pouch less than a week ago. These are quick to dig on the shagrat corpse, leaving the mother to go off hunting again. But as she reaches the valleys, the herds have left, so she follows them, to the coast.
Antarctica’s frozen coastlines are frequented by seabirds such as penguins during summer months, some of which still nesting. In the heart of winter, they are joined by a much more bizarre animal, the gannetwhale. These crawling, vaguely seal like creatures are a type of obdurodontine platypus; unlikely their bottom dweller modern relative, obdurodontines foraged pelagically, and during the Paleogene one lineage took this lifestyle to the extreme. Having adapted to life at sea, their forelimbs became flippers, and their snouts became long and thin, lined with teeth.
Never too common with giant penguins around, these marine monotremes were further displaced by cetaceans, now only occurring in these southern waters, before seals finally outcompete them. Like all monotremes, the presence of epipubic bones prevents long term pregnancy, so the gannetwhale has to drag itself ashore, producing a single egg that is incubated between its webbed feet and tail. They do this during winter, waiting in starvation until the summer bounty arrives.
Spotting the snowstalker, the brooding gannetwhales begin hissing, opening their toothed jaws. The many open maws discourage the marsupial, until she finds a more isolated individual. She rushes towards it… and, in a single motion, the gannetwhale’s rear end swings, and its venomous heel spurs stab the predator.
Spasming in pain, the snowstalker falls into the ground and dies. The gannetwhales poke the corpse with their jaws, before being bored.
Meanwhile, the cubs have managed to corner a shagrat, and kill it. This is a rare event when snowstalkers have hunted as a pack, and it quickly shows: the young turn on each other, and eventually only one is left, the others having walked off.
Long covered in tropical rainforests, Australia has began experiencing a general drying for the last few million years. This culminated in a drying of the extensive inland waterways, leaving several salt deserts dispersed across the central and southern areas of the continent.
As with all salt deserts, life can hardly sustain itself here, but one species has successfully shifted to the hostile Eyre Basin Desert. The cryptile is an amphibolurine agamid lizard, which has traded life in tropical rainforests for one in the open desert. Its skin is white, to blend in with the salt, except for its pink frill, which it flashes to attract mates.
Both sexes possess it, and a couple flashes at each other. After a successful mating session, the female now abandons the salt desert, needing non-salty soil to lay her eggs in. She chooses an outcrop, an “island” in the sea of salt. She climbs unto the rocks and crawls up the cracks. She finds a previous clutch, and throw it out, into the open.
Immediately, a herd of scrofas approach. These are chaeropodid marsupials, bearing long, slender legs ending on hooves, perfect for climbing the slippery rock like goats do elsewhere. Their snouts are rather long, probing amidst the crack for vegetation or small animals. They find the eggs, and have a feast, distracting them from another presence in the cracks.
This presence is the gryken, a large dasyuromorph marsupial related to quolls. Unlike its tree climbing relatives, however, it has a longer, weasel-like body in order to stalk prey underground, burying out digging mammals and lizards. But, as it turns out, it is also an efficient body plan to stalk the cracks, and it manages to close in on the scrofas, before pouncing.
In the ensuing attack, all but one scrofa disperse in all directions. This includes a young calf, still using the mother’s pouch, which falls down into the salt desert. Confused, the young cries out for its mother, wandering further into the salt desert.
It eventually finds water, the last remnants of this lake. They are covered in salt flies, and in turn these attract the cryptiles, which flare their frills to drive them into the open mouths of other cryptiles.
Confused and thirsty, the young scrofa drinks from the lake’s water, only to die from salt poisoning. The female cryptile has just arrived from the island, and happily runs around the corpse.
As the Panama finally closes, the Caribbean islands find themselves in a state of climatic instability, as the Pacific-Atlantic currents close and shift. A brief period of aridity ensues, dismantling the local forest ecosystems and opening up plains environments. The local fauna is quick to adapt, abandoning the forests for the grasslands.
Among these is the babookari, a type of xenotrichine monkey, exclusive to the Caribbean. Uniquely among New World monkeys, xenotrichines show adaptations for terrestriality, which started here with these brightly-colored denizens of the savanna. Like their distantly related Old World monkey counterparts, the babookaris form large groups, patrolling the grasslands for food. This particular day, they go down to the river.
There, have have constructed nets made from grass fibers. They are terribly inefficient, being dome-shaped so only the smallest fish can actually go there, but nonetheless the monkeys inspect their catch. This distracts them long enough for another group to approach. The babookari sentinel sounds the alarm and the group runs, but one is successfully isolated and meets a grisly end.
The hunters are carakillers, a type of caracara. In these islands, these falcons found themselves as top predators, and have lost the ability to fly and grown in size. Like most Australaves, caracaras lack wing claws, but the carakiller has compensated by developing wing spurs. These serve to hold the prey down while the bird eats it alive.
Amidst the frenzy, the male carakiller returns to its nest, only to find it raided by a rattleback. This is one of the last remaining american pangolins, a distant descendant of forms like Patriomanis. Isolated in the Caribbean, the rattleback has become a generalistic omnivore, not unlike the unrelated by similar south american armadillos. Spooked by the arrival of the carakiller, it sinks on the ground: unable to roll, it has compensated by developing spines, which hold it firmly. The carakiller pecks at it, but is distracted by a lightning strike.
It has caused a forest fire, that quickly spreads. The babookaris panic and run, but that only ends up being a feast to the carakillers, that skirt just past the flames.
Meanwhile, the rattleback buries itself, passing through the raging inferno unscathed… except for lung cancer.
Similar to Cuba, Jamaica undergoes a drying period, albeit more extensive. Areas of semi-desert form on vast areas of the island, dunes rising in accordance to coastoal winds.
Living here is the desert rattleback, a shaggier relative of its cuban relative. It forages most often by digging, and has a diet slightly closer to that of its Old World counterparts, feeding frequently on ants.
Today, however, it has chosen to munch on a few tubers. Digging them out, it reveals a colony of spinks, a type of eusocial, dwarf hutia, one of the few remaining small sized species before cricetids arrive. Like Old World molerats, the spinks have a central queen, while workers dig across the desert for tubers, occasionally dug out by other animals.
Not even seconds pass before a deathgleaner soars down. One of the world’s largest flying bats with a wingspan of 1.3 meters, these are particularly large noctules, that have specialized towards foraging on terrestrial prey. They are slender and rather competent on the ground, and a flock picks the spinks up with their strong jaws.
Deathgleaners are diurnal, taking advantage of desert thermals. When night falls, they return to the cave, and share their prey with other deathgleaners that have failed to catch anything.
Meanwhile, outside, its the spink mating season, and the male rodents make it across the desert, producing clucking sounds in order to attract potential mates. They are paired off just as the dawn rises, avoiding a deathgleaner’s attack. Time is warped, so its now daytime, and the hungry deathgleaners turn to the desert rattleback calf, circling it and doing absolutely nothing.
The mother arrives, and kicks them out. They take off quadrupedally.
100 million years ago
Random inland sea
The Early Cretaceous saw a large variety of reef types besides coral reefs. Sponge reefs, bivalve reefs, even crinoid reefs. This particular shallow, tropical water environment is dominated by a type of aquatic bennettitale, producing a single large flower. It bears no nectar, but its fleshy scent attracts the attention of many predators, which get sprayed with its pollen.
Among such predators are juvenile reef glider, a type of leptocleidid plesiosaur. They are drawn to the flowers, biting them off and unwittingly spreading their pollen. Juvenile reef gliders normally prefer large crustaceans, and easily mistake the flowers for such.
They, in turn, attract the attention of an ocean phantom, an ornithocheirid pterosaur with a wingspan of 10 meters. Landing on the ocean’s surface, it dives its long jaws, catching several reef gliders. As it feeds, a colony of spindle troopers surround it, stealing a few bits of meat before the pterosaur swallows them.
Spindle troopers are a species of marine gerromorphs that live commensally with aquatic pterosaurs. Staying on their pycnofiber coat, they feed on the dust particles and parasites, allowing their host’s tolerance. Occasionally, they will pick at open wounds, but this behavior is rare and their saliva helps heal damaged tissue, allowing them a safe perch away from predators.
The ocean phantom moves into deeper waters, just within reach of an adult reef glider, an animal about as large as a seal. It approaches the ocean phantom, but the spindle trooper colony has noticed it and swarm it, stabbing it with their proboscises filled with digestive acids. The plesiosaur is mildly irritated, and swims away.
A storm blows over, wrecking the reef. The ocean phantom simply soars away.
In this epoch, the Tethys sea is littered with islands, many of which one day will become part of Southeast Asia. For now, however, they are tropical archipelagos, where dinosaurs roam.
In a lowland forest, however, another megafaunal animal takes its steps. It is a toraton, a giant pleurodire turtle that has specialised to an herbivorous, terrestrial lifestyle. It weights 20 tons, rivaling the largest ornithischians and mammals. An elephant sized juvenile wanders off into a swampy lowland, feeding on some cypress canopies.
Eventually, however, it comes across a group of swampus. These are a particularly large (+30 kilos) species of sooglossid frog, bearing long nose tendrils in order to feel up its environment. They deposit their eggs inside a pond, because water-retaining plants on a swamp would be stupid. Highly social frogs, the swampus defend their brood, and thanks to a layer of chromatophores they are able to change colors, warning off potential predators.
Unfortunately, the toraton does not heed their warning, so a swampus jumps on it and bites its neck. Some of the frog’s skin toxins wash into the wound, and the toraton dies.
A rival group of swampus arrive to lay claim to the ponds, but the resident group warns them off. They venture into deeper water, only to end up in a lurkfish’s path. The lurkfish is a 4 meter long palaeonisciform, with long tendrils and ribbonny fins to help hide it in the swamp vegetation. It also can also generate an electric charge thanks to powerful caudal muscles. Usually, this is used to navigate itself in the swamp, but upon discovering a swampus it produces a more powerful charge, that instantly kills its prey. Having singlehandedly caught several swampi this way, the lurkfish feasts.
Some time later, a herd of toratons has come to the swamp. They are here incidentally, as they do not display parental care, and mate like normal turtles. They step on the pond, but the swampi are long gone, having retreated to deeper waters.
In this epoch of earth’s history, the Arctic is covered by lush forests. These are inhabitted by a variety of pterosaur species, such as the roachcutter, a fast, hawking wukongopterid. Unlike its relatives, which forage on the ground or on the branches, this is a fast aerial predator, hunting flying insects amidst the branches. With a wingspan of 20 centimeters, it is a fairly small pterosaur.
Small enough compared to the falconfly, a mesoraphidiian with a wingspan of 50 centimeters. Bearing powerful wingleg spears, it can pierce flying vertebrates, and it successfully ambushes the roachcutter. Feasting on it upon a branch, it leaves part of it on a bark opening, where its maggot resides.
Afterwards, it goes back on hunting, and it spots another pterosaur feeding on an early angiosperm. This pterosaur, however, is a spitfire, a type of nectivorous tapejarid that stores noxious chemicals within its nasoantorbitals. At will, these mix, resulting in a burning mixture that is expelled from its nostrils. The falconfly is hit, and it dies.
Another falconfly flies by and spots another pterosaur next to a flower, and backs away. It turns out that it is a false spitfire, however, another tapejarid that mimics the toxic spitfire, without any toxicity of its own.
The real spitfire flies to another flower, but it divides itself and attacks it, because it is actually a colony of camouflaged spitfire beetles, which warrant no explanation. They try the trick again, but the falconfly has learned to target spitfires before they recharge, so the spitfire beetles go hungry.
Displaying one of the few known examples of Cretaceous glaciations, the american midwest bears several mountain ranges. This distant, remote tundra is about as opposite to the stereotypical Mesozoic as it gets, and perhaps so it is its wildlife.
Living here year long is the great blue windrunner. At wingspan of three meters, this is the largest flying bird of the Cretaceous, able to survive here as it is too cold for pterosaurs and their membranous wings. An enantiornithe, it bears well developed hindwings, using them to increasing its airfoil when soaring.
Like all enantiornithes, it is superprecocial, young birds able to fly off within days after birth. All birds, adult or young, however, make use of the annual release of flying seed-fern seeds on the region. These seeds are eaten by the birds, but they are also collected by the silver ants, one of the earliest ant species. Gathering in large numbers, these insects have bright reflective exoskeletons to avoid UV radiation in the clear skies, but that only makes them easier for the great blue windrunners to catch.
The ants gather their bounty in their colonies on glacier crevices. They consume the seeds themselves, but they also offer them to puggles, a type of haramiyidan cynodont. The puggles live here, in the blessing of the ants, until their queen needs additional protein in periods of scarcity. Then it’s slaughtering time.
A volcanic eruption heralds the beginning of the Cenomanian, and everything in this section dies. The end.
200 million years ago
Basically the same thing as its TFIW counterpart.
On the aftermath of the Triassic/Jurassic extinction event, the oceans are rebuilding from this catastrophe. Among the earliest success cases are silverswimmers, marking the start of Decapoda as a dominant crustacean clade. These are a lineage of pelagic brachyurans, thriving far away from the continental shelf, that will endure until the mid-Jurassic, before further ammonite radiations outcompete them.
Silverswimmers are in turn consumed by flish, a lineage of pelagic coelacanths. They rely on their powerful flippers to “fly” underwater like penguins, chasing after their prey fast and furiously. Like silverswimmers, they too spend their entire lives far away from the coast.
Something resembles a swarm of silverswimmers, so a flish investigates. It turns out to be a rainbow squid, a type of massive belemnite at 25 meters in length, the largest marine animal of the Jurassic. Like all belemnites it has an internal shell, and so its skin is already covered in chromatophores, allowing it to change color efficiently. A second layer is also present on the membrane between the shell and the mantle, further enhancing its color changing mastery.
Rainbow squids spend most of their lives on the open ocean as well. At night they gather, and the ocean is alight with their many color displays.
Unfortunately, this draws in the attention of the sharkopath, a type of falcatid ratfish. Massive at four meters in length, they play second fiddle to marine reptiles, but they are still lethal predators, bearing bioluminescent tracks that allow them to communicate, forming ferocious pack hunting units.
They spot a rainbow squid. It tries to become invisible, but the sharkopaths detect its electrical signals and home in, biting it to death.
Along the eastern margins of Laurasia, cold currents render the coastline downright desertic, much like modern western South America. Here, humidity comes from the sea, along with plenty of flish and pterosaur corpses.
These are processed by the bumblebeetle, a type of relictual titanopteran. With a wingspan of 20 centimeters, the adult is an almost entirely aerial animal that does not eat, spending its entire adult life on the wing. The exception being when it finally lands on a corpses, upon which the abdomen will fragment and reveal its nymphs, which will proceed to fest on the dead body and mate, so that the adults already carry developing fetuses inside of them.
The bumblebeetle approaches one flish corpse, but its already occupied, so it flies away. The sun begins to st, and emerging from the desert are the mysteriously named desert hoppers. Though these resemble dinosaurs, they are actually larger descendants of Scleromochlus that have managed to survive on eastern Laurasia. These 30 centimeter high archosaurs bear dorsal scutes, forming an implacable armor in the tail nd back, but the rest of the body is covered by shaggy pycnofibers. They are herbivores, and hop around the desert like kangaroos in search of edible vegetation.
Unfortunately, some fall into death traps, often lined with plants. The animal dies a slow death by starvation and dehydration, nourishing the carnivorous plants. These also produce flish corpse-like flowers that attract the bumblebeetles and waste their time, carrying away the plants seeds so they they can grow on a proper fertilizer (ie dead meat).
Two bumblebeetles meet, fight, spread seeds everywhere and one adult dies while another gets to pass the genes.
Open ocean… again
During the Triassic and Jurassic periods, the oceans were dominated by forests of giant crinoids, attached to drifting wood and other floating debris. These reach truly spectacular lengths, some over 34 meters, and were certainly their own unique habitat, a shelter in the middle of the open sea.
Here, forest flish swim amidst the crinoids, fluttering quickly like any fish, except with their wings. To stay attached they developed claws on their pelvic fins, allowing them to hold on while resting. They possess long, curved beaks, used to catch small crustaceans.
Unfortunately, dwelling among the crinoids is a slithersucker, a type of bizarre, jellyfish-like cnidarian. It stays attached to the crinoids, its gelatinous folds forming webs that trap any unlucky small animal that happens upon them — including forest flish. Upon feeding, the slythersucker shapes itself into a sponge like form, hoping to attract the megasquid.
The megasquid is a massive (5 meters long) belemnite that lives exclusively amidst the crinoid forests. It is a shy animal, with an angular mantle that allows it to float thanks to internal shell chambers. It is a slow swimmers and prefers slow moving prey like sponges.
Unfortunately, once it eats the slithersucker, it dissolves, and cellular clusters spread across the body, concentrating on the brain. These alter the megasquid’s behavior, making it eject gas from its shell through a membranous operculum. This has a side effect of producing an odd sound, that attracts other megasquids, that allow the infection to spread quickly. Once the slythersuckers are out of the megasquid’s body, they refer, and may either perform the same trick or stay in “hunting mode”.
Living amid the crinoids is the squibbon, one of the earliest octopodiformes. It bears four long tentacles and several smaller ones; it is a lousy swimmer, but it has adapted to brachiate from crinoid to crinoid, while the smaller tentacles handle food and other objects. The eyes are long and located on stalks, mostly for camouflage against sponges and other elements, and the beak is also located on a stalk. It can change color and skin texture.
A young squibbon got separated from the rest and got caught by the megasquid’s tentacles. Though mostly a sponge specialist, it will on occasiona tackle larger prey. This however pisses off the other squibbons, which attack it, forcing it to release its prey.
The family climbs happily along the crinoids, before a giant ichthyosaur eats everyone.