I was completely exhausted and stressed from spectember on top of everything else, so I stopped pretty early. I decided for the last day I would come back. The title refers to what appears to be megalodon and livyatan returning in the future.

After the Anthropocene extinction wiped out larger marine species, vacant niches and different climates allowed for a brand new hyper-productive ocean ecosystem capable of supporting not one, but TWO giant predators.

On top is Gigaferesa monstro, a 13.5 meter descendant of the Pygmy killer whale that lives in small pods. On the bottom is Supralamma macrodus, a similarly-sized descendant of the porbeagle that is generally more solitary but can congregate in loose hunting groups.

Gigaferesa typically prefers to prey on smaller whales, while Supralamma prefers large, fully marine seals. However, there is a significant overlap in the two’s diet, thus they are fiercely competitive with and frequently attack one another.

15 million years hence, East Africa has fully split off from the rest of the continent, and has formed a massive island called Azania. This split, when flooded with seawater, created a new sea floor and an 8th ocean basin, called the African ocean. In it, the top predators are not sharks or any fish for that matter, but Sea Naddres, fully marine descendants of sea snakes.

These snakes have evolved a body plan very similar to sharks, dolphins, and most notably their extinct relatives the mosasaurs - hence their genus name Mosophis.
Sea naddres have a rather weak venom, instead they specialize in anything from suction feeding to lacerating and swallowing large prey in chunks.

Reference to the Blackbeard writing meme. This is the eclectic crow, a sophont corvid containing DNA from American, New Caledonian, and pied crows. In a world absent of humans, these 3 birds traveled to eachother’s continents where they met and shared thousands of years of history before interbreeding and ultimately going extinct, living on in this new species. At the time this image takes place in, the crows’ technology is roughly equivalent to mankind’s Bronze Age. This image takes place maybe 9 million years in the future, this is probably bound to change.

In a calm volcanic atoll approximately 10myh, a highly productive and diverse ecosystem, called a sea meadow, is slowly forming. It is comprised of meadow seagrass and the novel mangrove coral, capable of growing out of the water.
Underwater, the coral’s root-like foundations provide shelter and ambush spots for small predators like juvenile sheels, while the canopy supports amphibious fish like the climbing blennies. Even at this early stage of development, it has attracted several small and large species, and their diversity will only continue to increase.

Scramblennies are amphibious blennies
Sheels are eel-like sharks
Longloons are fully marine, ovoviviparous descendants of loons
Clubfish and Weeping spades are closely related gobies
Skyshears are large petrels
Arrows are fast-diving waterfowl
Swarmgulls are mid-sized terns
Whispy sirens are marine manatees, despite resembling dugongs (now extinct)
Mangrove shrimp are small lobster descendants
Meadow seagrass is a secondarily aquatic grass, which will soon attract pollinator crustaceans and aquatic insects when they blossom

Texas Gulf Coastal Plains 6 million years later. A Texan dragonole, descendant of green anoles, ambushes a group of shrubfowl, turkey-like quails.
Dragonoles are 8-foot long apex predators of the coastal plains, utilizing venomous bites to take down the largest of prey. They primarily hunt ground-dwelling birds, as well as rodents, bovids, tayassuids, and the occasional feral cats.

The salamanderfish is famous for being one of very few fish with a bendable neck, and also for being the only member ever known in its entire order.
I thought that would be a great base for the weird fish-tetrapod mix that is the piranhadon from Peter Jackson’s 2005 King Kong.
As always you can view entries like these sooner if you visit the Radiocene website or my Twitter account @miocaenus.

The manda (Manmosuda ioulos) is a salamander, the largest member of Amphiumidae, and the only extant species in the genus Manmosuda. Manda are native to the Southern United States, inhabiting estuaries and brackish wetlands along the Gulf Coast. Manda are ambush predators that feed on a wide variety of animals, including bass, catfish, small mammals, birds, turtles, other amphibians, blue crabs, and ebirah craylings. They themselves are occasionally preyed upon by American alligators and humans.

The name ‘manda’ is the shortened version of ‘manmosuda’, a portmanteau formed from the Japanese words ‘manmosu’ (mammoth) and ‘da’ (serpent) used in its scientific name - in reference to the creature’s mane of hair-like dermal papillae and serpentine body.

Manda are frequently hunted and served in local restaurants - their meat is often compared to alligator, tasting like a cross between chicken, fish, and frog legs. However, these salamanders cannot be farmed due to their massive size and great dietary demands. Instead, they must be wild-caught, which has led to a population decline in recent years and the conservation status of threatened.

Manda were frequently viewed as supernatural entities, rumored by natives to be guardians of a lost undersea empire known as Mu. By living in estuaries between rivers and ocean, manda represented a barrier or gate - and by attacking those who near their territories, they were preventing unauthorized access to the ocean and entry into Mu.

Golden Kong are one of the largest primates to ever exist, earning it the title "Eighth Wonder of the World" - they are the top generalist herbivores of their habitats, consuming bamboo stems, shoots, leaves, fruits, and bark. While their diet consists of over 90% plant matter, they may occasionally eat small vertebrates and megarthropods for supplementary protein. Kong use a special form of locomotion called suspensory or assisted bipedalism - in which the animals walk on their hind limbs and further support their weight by grasping onto surrounding trees. While capable of moving without external support, they have a strong preference for adequately forested areas. Kong are among the most intelligent animals to ever live, possessing advanced problem solving, tool crafting, complex communication, self-awareness, long-term memory, and an active care for their environment. They have been observed manually planting seeds of fruit-bearing trees and caring for their injured, even crafting medical braces for them.

At adult size, kong are virtually immune to predation. However, they must defend their vulnerable offspring from creatures like vinerats, large monitors, snakes, hermit crabs, and terrestrial crocodilians. Golden kong are currently listed as critically endangered, with fewer than 100 in the wild and 15 in captivity. This is primarily due to the devastating arrival of skullcrawlers following Dutch colonization as well as modern poaching and deforestation. The island has since been regulated and all captive kong are held in Monarch Rehabilitation and Research centers.

In a wealthy Louisiana home, a large boiled ebirah (Macrocheirus horridus) is being served for a massive feast, which can feed up to 20 people.
Ebirah is a species of enormous crawfish found throughout the United States Gulf Coast in brackish water. Ebirah are one of many arthropod clades to evolve sizes more commonly seen in vertebrates through lack of competition and sectioned shedding of their exoskeleton.
Ebirah can weigh up to 100 pounds before even their specialized anatomy can’t support their size and live up to 60 years in the wild.
As adults, their only predators are humans, alligators, and large gars.

The burrow of an endopede army. Endopedes are terrestrial, eusocial and detritivorous xiphosurans related to horseshoe crabs that are found throughout the world excluding Antarctica. Here the queen is surrounded by her “digger” offspring - whose primary role is to dig shallow nests. Endopedes are similar in lifestyle to isopods, feeding on any and all decaying organic matter, whether from plants or animals. Endopedes are special critters and an important part of nutrient return to the soil. Any questions? Ask away!

In the Northern Australian savanna, a lone gorosaur (Gorotherium megagnathus) has failed to hunt a young shimo. He is now suffering from severe freeze burns after the herd matriarch - who can be seen walking away - sprayed him with pressurized co2. Gorosaurs are giant carnivorous macropods that prey on kangaroos, small marsupials, lizards, and occasionally shimos. Shimos are Gondwanan metasuchians with pneumatized skeletons, allowing them to reach sauropod dinosaur-like sizes. Anything else you wanna know? Please do ask!

[Radiocene]

In a portion of the Hollow Earth Tunnels closer to the surface, a large adult foetodon or doug (Foetodon krichevskyi) bathes in the dust and sunlight. Foetodon are insectivorous rynchocephalian reptiles, part of the superfamily Dagonoidea from the Jurassic period. These reptiles are one of many species to have colonized the Hollow Earth Tunnels following the KPg extinction event. A foetodon’s main prey is the rock claw, a strange fossorial arthropod.

“Virus”

The Anti-Nuclear Energy Bacterium or ANEB (Geobacter okouchii) is a genetically engineered species of geobacter that specializes in bioremediation of contaminated water by converting nuclear material into an insoluble solid, preventing further spread. ANEB is being utilized by world governments in an experiment to source water from within or near the Hollow Earth Tunnels.

“Moon”

In Central Africa, a great varan (Anomaluras varanocauda) glides across the canopy during a full moon. Varan are giant scaly-tailed squirrels who use a strange ‘scale organ’ at the base of their tail to grip onto smooth-barked trees.

[Radiocene]

Somewhere in the Amazon Rainforest, a great hedoro bird, or hedorah, is being photographed for the first time. Hedorahs are giant flightless potoos with striking eye-like patterns on their throats. Hedorahs use these eyespots combined with their finger-like wing feathers to frighten and discourage the many predators South America has to offer.

In the Gulf of Alaska, a tiamat (Phyllospina tehom) hides among giant kelp in order to ambush a shoal of squid - its main food source. Tiamats are the largest sygnathids to ever exist, reaching up to 30 feet in length and weighing up to 700 lbs. Tiamat frequently surpass the giant oarfish in weight, making it a contender for the largest bony fish alive. In order to reach this size, tiamats evolved their external bony plates into lightweight, prickly integument - functioning more like a cactus than a suit of armor. While it is weaker, it is more painful to touch and thus leaves the fish with very few predators in adulthood.

In the fields of New Mexico, a swarm of abaddon (Akroknychus apollyon) flies overhead. Abbadon are small herbivorous arachnids in the family Tetranychidae. Abbadon take to the skies by ‘ballooning’ or catching static lift using silk produced from their mouths.

In the dense lowland rainforests of North Mondo Island (also known as Skull Island), a spore mantis (Sylatrachelos phasmoidia) molts out of its pupa form and into an adult. Spore mantids are giant weevils with fused elytra that feed on fallen coconuts. Interestingly, these aren’t the only megarthropods on the Mondo islands that consume coconuts.

The maguma or todora is a large aquatic descendant of South American 3-toed sloths, diverging around 10 mya. Maguma inhabit sub-Antarctic waters near the Antarctic peninsula where kelp and seaweed, their main food source, is available. The most striking feature of a maguma sloth is its pair of enlarged pseudo-canine premolars, used as sharp tusks for self defense. Maguma have slightly faster metabolisms than their arboreal cousins - this is a necessary adaptation to living in freezing temperatures. Another adaptation to the cold is the development of thick blubber, which retains heat efficiently in place of fur and keeps the animal bouyant. Maguma live a life not dissimilar to manatees, they travel in herds to discourage predators and care for few offspring at a time.

Was it really blue whale sized? I’d like to think it was the same if not bigger than the average at around 120 tons, seeing as only 1 individual was ever 200 tons.