Screaming into the Void

SCENARIO 1: the SU!Earth was just like ours up until the Gems arrived circa 6000 years ago and started terraforming the planet. Gem Terraforming was responsible for ALL of the differences in the map—the crater in Siberia, the presumed relocation of Western Africa (and parts of Central Africa) onto South America, the separation of the Americas, etc etc.

To put this in context: 6000 years ago, most of the charismatic Pleistocene (Ice Age) megafauna are extinct, with a few exceptions (namely the woolly mammoths on Wrangel Island and the Caribbean ground sloths). Horses might not've been domesticated yet but dogs, pigs, cattle, sheep, goats, cats, and chickens had. The Austronesian Expansion also hasn't happened yet, so humans haven't reached most of the Pacific Islands or Madagascar. Under this assumption, the world would've been pretty similar to ours, and we can probably assume the SU!Earth's biosphere was pretty similar to ours when the terraforming happened. My major questions/concerns are:

what the FUCK is up with Greater Afro-America. Unless the gems sterilized that half of the continent before they moved it, a lot of African wildlife are now present in South America. Who knows how this is gonna change the ecosystems—for starters, elephants will probably survive and thrive, which would radically change the South American landscape. I imagine other African wildlife without South American counterparts (gorillas and baboons come to mind) would probably survive as well. As for organisms that have African/South American counterparts, I have no idea what'll happen. Maybe lions and leopards and jaguars and pumas all find slightly different niches and coexist on the same continent. Maybe the old world vultures of West Africa will outcompete and displace the South American vultures. Perhaps none of the monitor lizards survive the exchange because they can't compete with tegus. I'm not gonna listing all the interesting African-American counterparts that would occur here because it'd take all day, but I am particularly haunted by the fact that the number of large ant-eating mammals has doubled (aardvark, giant pangolin, giant anteater, and giant armadillo) and the number of mid-sized arboreal ant-eating mammals has jumped from ~3 to 5 (anteaters vs pangolins, but treating the silky anteater as one species instead of a species complex).

The map in the screenshot doesn't show topography, which raises the question of whether smashing West Africa into South America created a mountain range in the Smash Zone, or if the Gems combined the two landmasses in way that didn't create a new mountain range (a pickup-and-drop strategy, perhaps). Regardless, I'm really concerned about South America's ecosystems. Did you know that the Amazon Rainforest is heavily dependent on windblown dust from the Sahara for nutrients? I doubt that system would remain unchanged even without a hypothetical mountain range on the eastern border of the Amazon.

North and South America are no longer connected, which is absolutely gonna fuck up the marine ecosystems. If we assume a reversal of what happened when the Isthmus of Panama first formed, the Pacific Coast of South America would warm up and the Caribbean would see a big influx of nutrients. Very real possibility that manatees would've spread to the Pacific Coast. Coldwater species on the Pacific coast like seals, sea lions, and Galapagos Penguins might've disappeared.

The removal of West Africa also leaves the Mediterranean a lot less isolated than it used to be—which will almost certainly cause a whole lot of extinctions. (Normally) the Mediterranean's only connection to the Atlantic is the Strait of Gibraltar, a tiny chokepoint that cuts it off from most of the Atlantic's business. Reconnecting the Mediterranean to Atlantic currents and tidal action will certainly fuck things up, but I frankly don't know enough about the Mediterranean to have any idea of what the specifics would look like

The massive fuck-off crater in Siberia really intrigues me because the only body of saltwater it's connected to is the Arctic, and I doubt most Arctic species would be able to colonize the warmer southern regions of what I'm calling the Siberian Sea. Without an obvious place of origin, I imagine it would be colonized by a random mix of adaptable Arctic species (like Harbor Seals and porpoises), salt-tolerant freshwater Siberian fauna (like sturgeons and Baikal Seals), and whatever saltwater species hitchhike a ride on migrating birds.

Not to mention how the crater would affect terrestrial ecosystems. The Central Asian Migratory Flyway is gonna get massively fucked up. I would not be surprised if the creation of the Siberian Sea somehow destroys the rest of the Eurasia's steppes, taiga, and tundra through the some type of large-scale disruption of climate cause-and-effects. Even if that doesn't happen, any species with a pan-Siberian distribution will be split into western and eastern populations.

What's up with the new archipelago(s) in the South Atlantic? They don't seem to line up with the Mid-Atlantic Ridge, maybe they split off of West Africa when it got moved? Maybe the gems just dumped the leftovers from some other terraforming project at a different part of the planet? I genuinely have no idea what to expect here, but whatever ecosystem emerges here will probably be unusually impoverished for an island ecosystem on account of being only 6000 years old. It would probably stifle any Atlantic-Antarctic ocean currents, though

SCENARIO 2: The other explanation for this weird map is that at least some of these difference predate the Gems' terraforming efforts. This is probably a less likely explanation IMO, but it's also where the speculation gets really fun! I have no idea how and when these changes would've occurred, but we're probably working on the scale of tens millions of years at minimum, which gives plenty of time for life to adapt to these changes, so here goes!

To start, a lot of the previously addressed points are gonna have some major impacts. The Mediterranean is a lot more exposed to the Atlantic and would probably look completely different. The geographic changes to South America and Africa would probably mess up the distribution of rainforest and grassland habitats. Of particular interest to me is that the Siberian Sea would've stifled a lot of faunal and floral migrations between western Eurasia and the combined eastern Siberian/North American region, assuming it's deep enough that it doesn't periodically dry out like the Mediterranean and Bering Seas did. This would probably have massive repercussions throughout the Cenozoic—the Holarctic as we know it probably wouldn't exist without a continuous swathe of terrestrial habitat across the Northern Hemisphere. But TBH, the no-longer-called-West-Africa and Siberian Crater issues are such major changes to Earth's actual geography that I have a hard time reconciling them as anything but the result of Gem terraforming. Even aside from those, a lot of the "smaller" changes on the map (which wouldn't cause too many differences if they only changed 6000 years ago) are gonna cause some major differences if they're old enough to predate the Gems.

The new archipelago in the South Atlantic! If this is a relatively recent island chain created by an alternate version of the Mid-Atlantic ridge, its wildlife might be vaguely similar wildlife to those of other South Atlantic islands like St. Helena and Ascension Island. Rails are inevitable. Alternatively, it might've bfffffeen colonized by wildlife that rafted across the sea from Africa. Monkeys, rodents, and tortoises got to South America this way, so maybe this archipelago is inhabited by giant tortoises and not-capybaras in addition to whatever flightless birds end up there. I wouldn't be surprised if the island ends up with its own ratite, since those flew to every other major Gondwanan landmass before they evolved flightlessness.

Alternatively, the new archipelago could be an old remnant of Gondwana, in which case it'll probably have a fascinating assemblage of relict taxa in addition to whatever rafts its way from Africa. Whatever reptiles or amphibians can deal with the colder climate will certainly be weird and unique. The flora will probably be roughly similar to that of Aussie/NZ/SouthAmerica (Nothofagus and such). It probably has a lot of weird metatherians and marsupials too, maybe some weirdo crocs if we're lucky. I'm imagining a fauna with predatory sparassodont-like metatherians, and a megaherbivore guild consisting of giant tortoises, ratites, big marsupials, and endemic hystricognath rodents of various sizes; maybe even monkeys! Non-therian mammals like monotremes, multituberculates, and/or gondwanatheres probably held on until the rafters arrived in the Eocene and might've included the last surviving members of their groups, but probably didn't survive to the modern day

New Guinea is a lot further away from Australia than it is in real life. In scenario A, the southern half of New Guinea was probably an unfortunate casualty of Gem Terraforming but in this timeline I'm gonna assume that the Australian Plate/greater Australian continent was just shaped differently. With the increased distance between Australia and the Southeast Asian archipelago, I doubt there'd be any substantial interchange between Asian and Australian wildlife. New Guinea would be part of the Indomalayan Realm instead of the Australasian—no cassowarries, no echidnas, and no tree-kangaroos in New Guinea. Perhaps rodents (including the "Old Endemic" Hydromyini) never make it to Australia, and their niches are instead filled by a family of possums or bandicoots.

Speaking of Australia, the Western half looks like it's isolated from the rest of the continent by sea, and will probably have a lot of unique species not found in the Eastern half. Two species of emu (western and eastern) perhaps? I don't know enough (any) Australian geography to know if Western Australia would still be mostly desert. They were probably connected during the Ice Ages, though, but if that's enough time for the SE Asian island wildlife to speciate, it's certainly enough for the Australias to do so.

The southern third of the Indian Continent is an island! This could mean that Southern India never collided with mainland Asia, but the island's proximity to mainland India makes me think it's more likely a New Guinea/Sahul situation, where the island connects to the mainland during the Ice Ages. The Western Ghats are already a biodiversity hotspot that houses a lot of relict lineages from the days of Gondwana, so if insular South India remained separate from the mainland most of the Cenozoic it probably retained even more unique wildlife.

There are a couple other minor details—the Greater Antilles archipelago in the Caribbean appears to be a single island, The Philippines are really close to Borneo, Sardinia and Corsica are once again a single island (or perhaps never disconnected)—that might just be due to the limitations of drawing a map for a kids cartoon, and thus might not reflect actual differences.

And saving best for last:

No Blood ver:

Some random close-ups: