Web Video / Alien Biospheres

The first animals of the Alien Biosphere.^note Anthostoma ("Flower Mouth"), representing a radially symmetrical clade, and Polypodia ("Many Feet"), representing a bilaterally symmetrical clade.

Alien Biospheres is a series of Speculative Biology videos by YouTube user Biblaridion. It starts with Biblaridion making a hypothetical alien planet with the help of fellow YouTuber Artifexian, then he creates various diverse alien lifeforms to inhabit it starting with two bodyplans: the radially symmetric anthostomes, and the bilaterally symmetric polypods, with 3D computer models used to represent each individual organism. The anthostomes later give rise to the shelled cephalopod-like tentaclostomes and their terrestrial descendants the lophostomes, while the polypods give rise to the spider-like sarcopods and their terrestrial descendants the osteopods. Each species exists to teach the audience about a real-world biological or evolutionary trend on Earth.

In October 2020, a video game project based on the series was announced at the end of Episode 8, though it has gone into Development Hell.

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This series contains examples of...

• All Planets Are Earth-Like: Downplayed. While the planet is pretty Earth-like to make it easier to come up with ideas for life forms, Biblaridion throws in some unique twists such as having a lower gravity than Earth, more hydrogen sulfide in the atmosphere, and a larger moon resulting in larger tides.
• All There in the Script: Until the end of Episode 14, the planet's name, Tira, was never given in the actual videos, only in Biblaridion's Discord.
• Anyone Can Die: Episode 14 features a mass extinction that ends the lineages of several species and clades. The synischians in particular get completely wiped out with the exception of the hybognathans.
• Apocalypse How: Episode 14 features a Class 4. Most multicellular life is killed off in Tira's mass extinction, as a direct parallel to many of the mass extinctions on Earth.
• Artistic License – Chemistry: As is pointed out in the comments of his first video, if you have a planet with significant quantities of both sulfur and oxygen in the atmosphere, then a single spark or lightning bolt will cause the entire planet to erupt into flames. Artifexian was aware of this, and desperately tried to warn Biblaridion not to add the sulfur, but to be fair he did a pretty poor job of explaining the danger.
  Biblaridion: Don't worry, I've totally got this... I think.
• Awesome, but Impractical: The synischians have a fused limb girdle that allows them to grow to massive sizes, but unfortunately limits their movement. The megalobrachids and the isopterygians have their size as their main defense mechanism, so they don't need much agility, but this becomes critical for the eudeinognathans, which are unable to adapt to some environments in which they are unable to employ their ambush hunting tactics (like in the steppe). In fact, this fused limb girdle and massive size ultimately leads to the synischians' demise during the extinction event, with the exception of the hybognathans.
• Back for the Dead:
  • The Isla Proxima species introduced in Episode 11 return in Episode 13 only to be driven extinct thanks to their island adaptations rendering them unable to compete with the large mainland herbivores and carnivores.
  • Several species and clades that went Out of Focus in previous episodes return in Episode 14... only to be killed off by the mass extinction.
• Bat Out of Hell: Averted and played straight with the pleuropterans. Although they evoke the image, the first pleuropterans and platypterans are actually gentle frugivores. The trope is later played straight when they evolve into the fearsome theropterans.
• Be the Ball: Desmostracans have a flexible shell that allows them to curl into a protective ball.
• Binary Suns: Subverted. In the first video, Artifexian initially suggests this idea, but Biblaridion turns it down since he doesn't want to get too crazy. "At least, not yet."
• Bizarre Alien Locomotion: The elastospondyls have an internal shell that acts as a sort of catapult that allows them to launch themselves through the air to catch prey. They later evolve into the opisthopterans, a lineage of flyers with large hindwings like that of the Triassic reptile Sharovipteryx.
• Bizarre Alien Reproduction: The tentaclostomes' digestive tract is connected to their reproductive system, so they mate and expel eggs through their mouths. Many real life invertebrates work the same way, such as sea cucumbers.
• The Bus Came Back:
  • The marine organisms were left Out of Focus after the invasion of land. Episode 7 finally put them back in the spotlight describing how they evolved, also with some land-bound organisms adapting by returning to the water.
  • After being Out of Focus for several episodes, the malacoformes finally get a spotlight in the first section of Episode 9, which highlights their adaptations for survival in a tropical jungle.
• Can't Catch Up:
  • With the exception of the opisthopterans, who convergently evolved a primitive skeleton and active respiration in the process of specializing for flight, and the malacoformes, who are too small for an internal support structure or active respiration to provide a meaningful advantage, the lophostome clades have found themselves outcompeted at every turn by osteopod clades due to their inefficient internal support structures and breathing mechanisms.
  • In Episode 13, when the continents re-merge with each other, several clades from the Eastern continent that were less adapted to the harsher conditions of the Western continent get easily outcompeted by their Western continent rival clades. The Isla Proxima species had it the worst by far, almost all of which were driven to extinction due to having adapted to an environment without large herbivores or large predators, which the land-bridging of continents introduced.
• Cephalothorax: The sarcopods have a front segment that contains both the head and forelimbs, much like that of arachnids and crustaceans on Earth.
• Changeling Tale: The apatocheirids are a lineage of brood parasitic rhamphodonts that sneak into the nests of their close relatives, the acrocheirids, to deposit their own grubs alongside the acrocheirid grubs. The imitation grubs kill off the real grubs to prevent suspicion from the helpers at the nest.
• Chest Burster: The deinoglossids are a clade of parasitoid kentrodonts that reproduce like parasitic wasps, using their pointed oral ovipositors to inject eggs into their prey, and keeping them alive as living incubators until the larvae burst out.
• Chromatic Arrangement: Chromatophytes, a group of tropical chemophytes filling a similar role to flowering plants on Earth, have red leaves, blue reproductive filaments, and green fruit.
• Circling Vultures: The magnopterans are a lineage of large opisthopterans that fill a similar niche to vultures, soaring over deserts with their long wings in search of carcasses.
• Combat Tentacles: Tentaclostomes have spiked tentacles surrounding their mouth that they use to catch and kill prey.
• Crippling Overspecialization:
  • The deinognathans are gigantic ambush predators designed to prey on large organisms, but begin to decline after the forests they once inhabited are mainly replaced by grassland, making it difficult for them to hunt due to their inability to sneak up on prey, as well as being unable to chase after it thanks to their fused limb girdle (think if your spine was a single fused bone rather than a stack of disks) limiting their agility. This was also one of the reasons that led to their ultimate demise in the mass extinction, with only the hybognathans surviving.
  • Most of the species that were overly-suited for rainforest environments died out when the extinction event wiped out the altiphytes and rainforests. These include the phyllophorae, harpactopods, aspidonts and tanybrachids.
• Early Installment Character-Design Difference: In Episode 3, the ancestral acanthopods were Anomalocaris-like creatures with a shark-like tail fin. In Episode 7, which goes into more detail about the acanthopods' diversity, the ancestral form is more eel-like. The previous version is shown only briefly at the beginning of said episode.
• Easter Egg: One illustration in Episode 11 features a thyreostracan with four brightly-colored opisthopterans perched on its shell. If one looks closely, each opisthopteran's coloration corresponds to a different pride flag, specifically the rainbow, bisexual, pansexual, and transgender flags, since the episode was produced during Pride Month.
• Extra Eyes: The polypods and tentaclostomes both have six eyes, although organized in diferent ways.
• Eye on a Stalk: The tentaclostomes have a pair of stalks with three eyes on the ends of each.
• Fantastic Fauna Counterpart: There are many examples of this trope, all done intentionally to demonstrate convergent evolution with Earth organisms.
• Fantastic Flora: The "plants" on this planet have a symbiotic relationship with red photosynthetic algae, making them red instead of green, and absorb sulfuric chemicals from the atmosphere as well as sunlight.
• Flight: The elastospondyls with their jumping ability eventually evolve membrane hindwings to augment their jumps, allowing them to gain the ability to glide. They further evolved into the opisthopterans capable of proper powered flight. In Episode 9, a lineage of osteopods known as the pleuropterans develop flight as well, with a membrane connecting all four limb pairs.
• Flower Mouth: All tentaclostomes have a mouth like this. In fact, the very meaning of the name Anthostoma is "flower mouth."
• Four Legs Good, Two Legs Better: A variation. The onychodonts, allobrachids, brachiocephalians, and acrocheirids evolved to become hexapedal instead of octopedal like other osteopod clades, freeing up their forelimbs to manipulate their environment. Some lineages exaggerate it after the mass extinction, developing an extra pair of "arms" and becoming quadrupeds.
• Freeze-Frame Bonus: In Episode 11, when Biblaridion mentions the biological concept of a refugium, the logo for Biblaridion's other worldbuilding project of the same name flashes onscreen for a single frame.
• Gender Bender: The osteopods are sequential hermaphrodites, and some individuals in a group can turn female if the gender balance is uneven, like clownfish on Earth.
• Giant Spider: While the osteopods are genetically distinct from true spiders due to evolving on a different planet, their eight legs, six eyes, mandibles, pedipalps, and cephalothorax cause them to look the part.
• Grim Up North: The northern regions of the planet are covered in cold dry tundra, which is covered in detail in Episode 8.
• Hell Is That Noise: In Episode 12, many of the organisms are given vocalizations, and some of them, such as the bellowing trumpets of the camarabrachids, the deep booms of the sphenoceratans, and rasping chattering growls of the xenopsids, are quite unsettling.
• Hero of Another Story: Much like insects on Earth, the malacoformes make up the vast majority of the alien biosphere's species, but they are only discussed briefly. They were touched upon more in Part 9, regarding their survival adaptations in the tropical jungles. They were also briefly mentioned in Part 14 to be one of the few clades that survived the extinction, just like how most insects survived the K-T extinction.
• History Repeats: When they first came into land in episode 5, the osteopods first exploited different diets that those of the prevalent diplosthomes, but ended up outcompeting them in most of the megafaunal niches due to their more efficient breathing and support systems in episode 6. Millions of years later, the pleuropterans avoided competition in the aerial niches with the predominant opisthopterans by specializing for different diets, but their more efficient support structures allowed them to grow to sizes far beyond what their competitors could, and ended up giving rise to the theropterans.
• Hive Caste System: The oryctocheirids are a lineage of trypanocheirid that are eusocial, much like mole rats or termites. They include a large queen who reproduces, workers who collect food and resources, soldiers with enormous claws for defending the nest, and dispersers who leave to mate and start new colonies.
• Innate Night Vision: The lystrocheirids have large reflective eyes designed to see in the low-light conditions of the desert nights. The xenopsids develop a similar adaptation in Episode 12, as competition with other more specialized species forced them to become nocturnal.
• Introduced Species Calamity:
  • This happens twice in Episode 11 on Isla Crescentia. First, a lineage of platydonts called the xenodonts raft to the island and outcompete the native desmostracans, the notoforms. Then when the ice age comes along and decimate most of the native population, a lineage of allodonts called the eriotheres are able to cross the sea ice and outcompete the remaining species.
  • Inverted in Episode 13 when Isla Proxima rejoins the mainland and the native island fauna are outcompeted by their mainland cousins. Played straight with the western continental fauna, as due to being more well-adapted to a wide variety of climates, they mostly outcompete their tropical eastern cousins save for a few adaptable generalists.
• Luring in Prey: The phyllophorans have evolved to mimic chromatophytes to attract nectar and fruit-eating animals and then ambush them.
• Lightning Bruiser: The onychodonts due to their large size, weaponry, and cursorial lifestyle; they are the apex predators of the steppe as a result.
• Living Dinosaurs: An alien version of this trope. The hybognathans are the only clade of synischians to survive the mass extinction and unlike other surviving species changed relatively little following the event, even being called "a bizarre relic of a bygone era". It's even mentioned that their fused limb girdles would be unlike any other living osteopod post-mass extinction.
• Meaningful Name: Many of the clades have scientific names that refer to a defining physiological feature they possess.
• Monster Mouth: Some truly bizarre mouths have been featured in this series, with even weirder likely to come.
• Monstrous Mandibles: Many lophostomes and osteopods have mandibles with sharp tooth-like cutting surfaces, giving this effect.
• More Deadly Than the Male: The female amphidonts are larger and more aggressive than the males due to evolving in a location with scarce resources, which forced them to become territorial. This results in their more social descendants, the xenopsids, developing a matriarchal society much like hyenas.
• Nested Mouths: The ceratodonts are a lineage of stenopsids that emerged after the mass extinction, which developed protrusions of their skull known as exognaths (inspired by a similar structure seen in the extinct hell ants) that combine with their pedipalps to form what is essentially a second set of mandibles, with their true mandibles being hidden underneath.
• Never Smile at a Crocodile: Justified and discussed in episode 7. Although there are no crocodilians on the planet, the odontognathans evoke the image as it is the optimal design for the niche of semi-aquatic ambush predators.
• Nightmare Face:
  • Observe the horrifying results of combining Flower Mouth with More Teeth than the Osmond Family in the coleostracans.
  • The xenopsids, with their large forward-facing black eyes and large tusk-like fangs, look even worse. Unsurprisingly, their name translates to "strange face", while the genus featured in the video, Agriops, has a name that translates to "fearsome face".
• No Biological Sex: The anthostome larvae are sexless until they reach maturity.
• Noble Bird of Prey: The sphenopterans are Tira's answer to this trope, being hawk-sized flying pursuit hunters with curved talons for seizing prey.
• No-Neck Chump: Due to having multiple eyes that grant them a wide field of vision, and long pedipalps that can easily reach for food, the sarcopods have no need for a neck.
• Non-Mammalian Hair: The thylacopods and thecopods both developed their ancestral setae into a layer of thick fur-like material to protect themselves from the cold tundra. This is downplayed with the oryctocheirids, which develop special whiskers to help them sense underground.
• Nothing Is the Same Anymore: Thanks to a mass extinction event in Episode 14, several previous clades were completely wiped out and rendered extinct, leaving the survivors to evolve and replace the niches the extinct clades once occupied.
• Oh, Crap!: Artifexian has this reaction when Biblaridion suggests messing with the atmosphere and adding a high dose of hydrogen sulfide. As detailed under Artistic License – Chemistry, this would result in a planet that would be set on fire by one bad lightning strike (which the series ignores for the sake of plot).
• Out with a Bang: Due to being prey animals with a low probability of surviving past the mating season, trypanocheirids are semelparous, dying shortly after they reproduce.
• Parasitic Horror: Episode 10 introduced the ectoparasitic myzognathans and the endoparasitic echinostomes, the latter of which are especially gruesome to behold.
• Poisonous Person: The chloroderms and cyanoderms have developed poison to defend themselves from predators, while the pronocanthids have venomous quills for defense and kentrodonts developed venom from digestive glands near the mouth to aid in catching prey.
• Rule of Cool: Biblaridion admits this is the reason he came up with such traits such as the amount of legs and eyes on the osteopods and the high amount of sulfur in the atmosphere, as these details were more for the sake of making the planet as alien as possible instead of for plausibility.
• Sacrificial Lion: Several significant species that were heavily elaborated on and featured in previous episodes end up becoming extinct due to the mass extinction event, to show how devastating the extinction event is.
• Sea Monster: Several of the aquatic megafauna can qualify as this, especially the temnopods and thalattotheres.
• Sensory Tentacles: The anthostomes have eyes and vibration-sensitive setae on their tentacles.
• Shock and Awe: The astrapophorans are a lineage of diplocirrid (catfish-like acanthopods) that have the ability to generate a powerful electrical field useful for both stunning prey and in self-defense, much like many Earth fish.
• Shout-Out: One of the named species of animal, Cephalocarcinus elvari, literally translates to "Elvar's headcrab."
• Snakes Are Sinister: The kentrodonts, venomous elastospondyls with elongated bodies, seem to be Tira's answer to snakes, particularly vipers.
• So Last Season: The secondary through-gut evolved by the diplostomes was a massive advantage when it first appeared, allowing them to get more energy from their food and letting them become the biggest land animals at the time despite some of their anatomical constraints. However, this became significantly less of an advantage when the osteopods arrived on the scene, because they not only possess more efficient supporting structures and respiratory systems, but they also had through-guts of their own.
• Square-Cube Law: This is discussed multiple times throughout the series. For instance, despite lacking an internal skeleton, the lophostomes are able to grow much larger than they would on Earth due to the lower gravity.
• Starfish Aliens: Literally everything, and we're not likely to see any other type of alien. For example, the lophostomes all breathe through holes on either side of their face that used to be tentacles.
• Stealth Pun: The tanybrachids are spider-like creatures with monkey-like lifestyles. In other words, they're literal spider monkeys.
• Theme Naming: Biblaridion tends to name related clades using the same Latin noun, but described using a different adjective. For example, many polypod clades end in -pod, ("foot") and many anthostome clades end in -stome. ("mouth")
• Tuckerization: Many of the organisms have scientific species names derived from Biblaridion's Patreon followers.
• The Worm That Walks: While not literally walkers due to being sessile plants, the zygophytes are a clade of colonial chromatophytes with different individuals filling a different role, with some acting as roots, some as a stem, some as leaves, and some reproducing.
• Vegetarian Carnivore:
  • While most onychodonts are predators, the primitive allodont lineage still retains a decent amount of plant matter in their diets. Their thecopod descendants use this to help them survive in dry climates such as deserts and tundra.
  • After the mass extinction, two lineages of xenopsids, a typically predatory clade, develop into full herbivores, including the aratrodonts, a lineage of ceratodonts which developed their exognaths into long antler-like structures, and the teleopsids, a lineage of more primitive xenopsids that become the dominant large herbivore in climates too cold for the large herbivorous rhamphodonts.
• Wham Line:
  • The end of Episode 13 has one:
    "In the next episode, the era that has lasted for over 200 million years will finally come to an end with the advent of a mass extinction"
  • The end of Episode 14 has one too:
    "However, along with the menagerie of forms that appears after the mass extinction, the new era will see the emergence of one particular adaptation, one with the potential to shape the future of the entire biosphere. Next time, in the final episode, we discuss the evolution of sapient life."

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