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For :iconinkgink:’s May contest in :iconspec-evo-club:.  Theme:  TROPCIAL


The jungles of Great Lakes Earth boast quite a history.  Since 444.4 million years ago, all plants on Great Lakes Earth were vascular seed-bearers.  Even though rainforests had been around for longer than that, modern rainforests would not make their debut until the Cretaceous Thermal Maximum 144 million years ago, when a dramatic increase in carbon dioxide raised the global temperature by nine to 15 degrees Fahrenheit.  This resulted in the extinction of the ginkgophytes (ginkgoes) and the gnetophytes (gnetums and ephedras).  The conifers remained untouched, consisting of araucarians, plums (“fruits” belonging to Cephalotaxaceae, not Amygdaloideae like back home), podocarps, cypresses, redwoods, umbrella pines and “China-firs”, but now spreading to include true pines.  The cycads, which had been in decline since the Permian Ice Ages from 250 to 200 million years ago, suddenly witnessed a dramatic spike in diversity.  Along the way, what little remained of the vacancy was filled in by a new kind of plant—the angiosperm.  The flowering plant.


As a result of the CTM, Great Lakes Earth during the Cretaceous period was under only one climate—Af, tropical rainforest.  Which meant that, from pole to pole, the plants, invertebrates, fish, amphibians, reptiles, dinosaurs and mammals would evolve madder than a hatter and establish the ultimate diversity—at the cost of being the ultimate specialists, as is the case with tropical rainforests back home today.


But the angiosperms would be ecologically rare until 65 million years ago, when a series of lava eruptions from western North America created an igneous province covering an area of one and a half million square miles and a total volume of one million cubic miles. The lava had been flowing for a duration of ten to 12,000 years, more than fast enough to create a mass extinction. When they cooled, actually, they would mark the initial foundations of the creation of the Great Lakes of the West.  The first stage of the extinction was moderate among the terrestrial species as the lava belched out dense clouds of carbon dioxide into the atmosphere.


But then the warming came to a point where, as was the case at the end of Great Lakes Earth’s first ever ice age, the entire global supply of methane hydrates melted and entered the atmosphere as methane gas, heating up an already warm planet by 15 degrees Fahrenheit. Desertification ran rampant. Each continent was subject to its own dust bowl, leaving the coastal margins the only real estate available.


100% of the cycads became extinct, as did 75% of the conifers.  Such losses provided much more than enough space for the then-ecologically-rare angiosperms, the flowering plants, to branch out and diversify. That said, not all of them survived the End-Cretaceous event.  In fact, 60% of the angiosperms were believed to have died off 65 million years ago.


It wasn’t just plants that had a hard time 65 million years ago.  The entire invertebrate system had been cut down by half.  Seven species of cartilaginous fish (sharks) out of eleven could no longer boast about their evolutionary immortality.  None of the jawless Agnatha survived the End-Cretaceous extinction event.  Seven species of bony fish out of 15 dessicated into extinction.  97% of all the amphibians were gone.  One-third of Squamata, the lizards and the snakes, died out.  Half of the turtles did not make it.  Of all the extant reptile supergroups, Crocodylomorpha was hit the hardestfour species out of five had vanished, leaving the only survivors being Alligatoridae and Crocodylidae.  Some groups of reptiles were completely wiped out as a result of the End-Cretaceous event, like the rhynchocephalians (tuataras) and the choristoderans (“false crocodiles”).  The End-Cretaceous event wiped out 70% of all the dinosaurs (ancestral and avian) and 85% of the mammals.


In all, 60% of terrestrial species and 85% of marine species became extinct 65 million years ago.


When the planet recovered two million years later, the change was unimaginably massive.  The climate was so much cooler and drier than the Cretaceous that Af—the tropical rainforest model—did not extend beyond latitudes of 55 degrees.  Back home, by today’s standards, that would mean hot, steamy weather as far north as Hadrian’s Wall.  Outside of that zone, the climate would be classified by Wladimir Köppen as “Csa”hot-summer Mediterranean.  The global jungles used to harbor conifers and cycads, the floral ecological minority consisting of their angiosperm upstarts. After the End-Cretaceous event, the lowland jungles were exclusively angiosperms. The conifers that survived the End-Cretaceous event sought refuge in the cooler, drier, rockier highlands.  This was the point where the ancestral pines and plums diversified into spruces, larches, firs, cedars and hemlocks.


From 45 to five million years ago, the Icing of Antarctica reduced the Af latitudes from 55 degrees to 30 degrees (as far north as the Florida Peninsula, as far south as Lesotho).  But then, five million years ago, the global temperature experienced a sudden downward spike, speeding up the gradual cooling process into an ice age that killed of 50% of terrestrial species and 65% of marine species.  This sudden cold snap reduced the tropical rainforests to their equatorial limits.


Before this happened, the rainforests would have been identical in resemblance to the jungles back home.  But the rainforest ecosystem was most vulnerable, as countless species of plants became extinct and with them, animals specialized to eat or even look like one certain kind.  So is the rainforest of Great Lakes Earth gone?


No.  But you would not recognize it.  The major absence of so many jungle plants means an increasing diversification of palms, ranuncalians (poppies, barberries, buttercups, etc.), planes, bayberries, buckthorns, grapes, violets, legumes, oleasters (Great Lakes Earth olives), roses, gourds, cashews, mahoganies, soapberries,  heather, myrsines, teas, camillas and bamboo.  Back home, the vertical gap between the canopy and the forest floor is 150 feet, with the occasional “emergents” pushing upward at 200 feet.  On Great Lakes Earth, that same gap is 50 feet, 100 at the emergent.  These forests are polka-dotted by vast copses of timber bamboo rising 115 feet tall.  In fact, the rainforests of sub-Himalayan Asia have a higher concentration of bamboo than anywhere else on Great Lakes Earth.  Also, due to the latest mass extinction being so recent, diversity is not as big as back home.  On Earth, one hectare (two and a half acres) of Malaysian rainforest has 180 species of tree (in comparison to one hectare of temperate deciduous forest, which has ten).  For every square meter of rainforest, there can be as much as 11 square meters of vegetation.  There are 3,000 identified species of fish in the Amazon River alone—a much higher number than the whole North Atlantic.  On Great Lakes Earth, one hectare of rainforest has, on average, 21 species of tree, and the Amazon has only 500 species of fish identified so far.  For every square meter of rainforest, there is only six to seven square meters of vegetation.  Not one species of owl can be found in this habitat on Great Lakes Earth, as the feathers that make them silent hunters are so fine that they are not waterproof, so they can be found instead on temperate and subpolar habitats with less frequent rainfalls.  Nor can you find eagles on a Great Lakes Earth rainforest, as their stocky frames better suit them in open or semi-open habitats.


There is no rainforest on Great Lakes Earth that is more alien to our eyes than in South America.  Since splitting from the rest of Gondwana—the southern supercontinent—roughly 100 million years ago, South America had been what geography students would call an “island continent”.  (For further clarification, sub-Himalayan Asia split from East Africa 150 million years ago, Antarctica from Southern Africa 60 million years ago.  In turn, Sahul split from Antarctica 45 million years ago.)  In its isolation, South America became the nurturing point for some really alien evolutionary paths.  After the End-Cretaceous event 65 million years ago, the mammals who were stuck on South America blossomed into two major groups—the herbivorous meridiungulates and the carnivorous creodonts.  No one knows how the parrots, originally from Africa, or the monkeys, originally from Europe, got there or when.  Maybe they were blown over by hurricane-force winds, since the climate was still warmer and wetter than today, which meant more intense weather.  Maybe they were cast away on vegetative rafts by tsunamis or earthquakes.  However they got there, they found a land with no competition, so they spread out and prospered high up in the canopies, while the drama between Astrapotherium and Hyaenodon played out on the dark, muggy forest floor.


In the canopy of prehistoric South America, marmosets and tamarins sucked the trees of their gum and sap.  Titis, sakis and uakaris could not jump from tree to tree, so instead seesaw the branch back and forth to get a better reach of their sole diet—young fruit.  With such long, prehensile tails, long legs and broad diets, the woolly, howler and spider monkeys seemed prepackaged for any environmental change.  But the monkeys who took the gold by surviving the Pleistocene mass extinction were Aotidae (night monkeys), Cebidae (capuchins) and Saimiiridae (squirrel monkeys), who survived by not being exclusively tied to the canopy in their search for food like the others were.  The skies were alive with parrots of a variety unseen back home.  Apart from the familiar macaws, conures and Amazons, there were also cacadors, parrots with a taste for meat (like Falconiformes and Strigiformes elsewhere on Great Lakes Earth); faixas, parrots with bills so strong that they reached food by stripping bark off trees; and toucans, parrots who had such large, extravagant bills just like the toucans back home, who are more closely related to woodpeckers than parrots.  Microbats avoided competition by being small with an acquired taste for insects and nectar.  (On Great Lakes Earth, the bats come in two separate orders—Microchiroptera, bats who see the world with their ears and have a European origin; and Megachiroptera, bats who follow their nose and have a North American origin.)  There also lived whole flocks of hoatzins, who avoided competition by eating leaves and nothing else.  Other birds included trogons and turacoes.


Then, five million years ago, after 95 million years of isolation, fate gave South America a turn.  A landbridge formed, connecting North to South America, attracting immigrants.  The Twins were tall enough to not make migration easy. One twin is currently 6,684 feet above sea level, the other 9,698 feet.  The combination of changing habitat and competition from the northern invaders spelled the end of the meridiungulates, the creodonts, the marmosets, the tamarins, the titis, the sakis, the uakaris, the spider, woolly and howler monkeys, the hoatzins, the trogons and the turacoes.


But who were the northern invaders tasked to fill in such a vast vacuum?  Turns out that camels, sheep, boars, pandas, chipmunks, marmots, hyraxes, grice, kingfishers, swiftlets and cats of the genera Puma and Lynx.


Why not bears?  After all, they have proven, both on Great Lakes Earth and back home, to be more-than-competent mountaineers.  Our best guess could be that they were occupied filling in the niches left behind by their most direct competitors, the bear-dogs and the entelodonts, who had gotten too big and too picky for their own good.  You could say that this is the same reason that the roaring cats of the family Pantheridae did not make the crossing either—filling in the niches left vacant by Machairodontidae, the saber-toothed or mastiff cats.


With the bears and roaring cats busy, the pandas and the regular cats (family Felidae) had South America to themselves.  The pandas diversified into species similar to the kinkajous, olingos and cacomistles that we still have back home but became extinct during the Pleistocene Big Freeze on Great Lakes Earth.  One other genus of panda, Pseudarctos, resembles the koalas we have back home in both physical appearance and behavior.  One species of the genus Lynx becomes 14, ranging from insect-eaters the size of a domestic kitten to ocelot-like stealth climbers.  One species of the genus Puma becomes four, from the yard-long eyra to big-game hunters standing a yard tall at the shoulders and weighing 465 pounds.


On Great Lakes Earth, South America is the only place where you can find jungle pigs, like Potamochoerus porcus, the Red River Hog.  There are seven species of pig in South America on Great Lakes Earth, the largest being Hylochoerus meinertzhageni, the Giant Forest Hog, averaging seven feet in length, four in shoulder height and 600 pounds in weight.  Still, the giant is an herbivore, though carrion is another staple in its diet.


While the pigs forage on the forest floor, the camels of the genera Lama and Vicugna look up to find food.  Their long legs and long necks give them a good head for heights.  Leaves are fibrous and poor in nutrients, so the camels focus instead on twigs, nuts and fruits.  If need be, they can even rear up on their hind legs to reach their desired meal.  These same genera can still be found in the foothills of the Andes, but in smaller densities, so as to avoid competition with the blue sheep and gorals that truly dominate this long, volcanically active chain.


Like the sheep, marmots stay in the high peaks of the Andes, leaving the lowlands open for chipmunks and hyraxes.  Though the chipmunks haven’t changed from their nothern counterparts (so many fruit and nuts in the jungle, so why bother?), the hyraxes have evolved into giants.  Hystricomorph rodents have been extinct on Great Lakes Earth for five million years, so the hyraxes are the capybaras and guinea pigs of that alternate Earth.


The New World parrots have not changed a thing in the last five million years.  Nor have the squirrel monkeys, night monkeys or capuchins.  So the monkeys remain under constant alert for a hungry cacador, like the largest parrot in Great Lakes Earth, Erinyia moorei, the Furious Cacador, an indiscriminate meat-eater with a seven-and-a-half foot wingspan carrying a 25-pound body.


Herpetologically speaking, the reptiles and amphibians don’t pose much of a difference from back home, but with one inconspicuous exception—on Great Lakes Earth, South America has no snakes.  Never did, not even during the Panamanian migration.  The lizards look identical, as do the caimen.  But it is the turtles that are worth noting.  Giant mainland tortoises are not unique to South America on Great Lakes Earth, but the continent does boast the largest—Chelenoidis titanis, the Long-Necked Tortoise, weighing one solid ton and having a carapace 15 feet long.  True to its name, its neck alone measures seven feet long, perfect for the tortoise to reach into plants above ground level.  No predator would dare tackle an adult Long-Necked Tortoise, but the young are particularly vulnerable.  For maximum defense against predators, females gather around the bamboo copses, and each one can lay anywhere between 80 and 150 eggs, each one the size of a baseball.  (A larger egg means a more developed baby.)


The Amazon has no dolphins and no otters.  Instead, the caimen have to share the superriver with sharks, salmon, trout, carp, cod and true eels.  As with all rivers on Great Lakes Earth, the Amazon in its mature and old age stages are inhabited by “worm forests”—reefs consisting of bivalve mollusks, barnacles and canalipalaptan worms.  However, unlike marine worm forests, the Amazon is so murky and full of sediments that the worms can’t afford to be photosynthetic.  Instead, they gather the sediment particles and feast on them.

For :iconinkgink:'s May contest to :iconspec-evo-club:


And what continent could get more tropical than South America?

On another note, I originally wanted to put in the arthropods, but the differences between ours and theirs are just too global, and "slugs" being flatworms instead of mollusks are for another theme.
Lediblock2 Featured By Owner May 6, 2017
Question: What sorts of creodonts and meridiungulates inhabited GLE South America that didn't evolve here?
Jdailey1991 Featured By Owner May 6, 2017
Depends on which of them were adapted for closed habitat and which for open habitat.
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May 5, 2017
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