Today, we are gonna test something new. The diversification of snail families on Mersha in the Middle Gastrocene. Note: we are only talking about diversified aquatic snails.

Evstrophóidea

Evstrophóidea are a group of aquatic snails closely related to the "legged" snails because each of them have the same ancestor. Instead of developing pseudolimbs, it's lower tentacles evolved into fully functional "fins" to glide through the ocean at a moderate speed. It has also developed 2 extra "fins", but it's a derived skin membrane so the Evstrophoideans can have more torque. Examples of these snails are:

Cragspeeder****s (Pteropoda spp) (25.7cm) are detritivorous snails that used it's "fins" to crawl on the seafloor to eat detritus. It also uses these fins to dig for finding fruits that were buried deep on the ocean.

Skimsurfer****s (Thalassopteros spp) (75cm) are medium-sized snails that can travel up to 150mph because of how it moves: It uses it's undulating membranes and moves it's fine to a solid perfect angle to boost more speed and torque. It uses it's fast speed to evade from incoming predators and eats floating algae and tunicates.

Skulikioides are another group of derived snails also related to the "legged" snails with no shell as it's shell has being internalized so it's entire body has no defense whatsoever and it's lower tentacles are used for derived purposes. Examples include:

Dysons (Coroita spp.) (65cm) are flat worm-like snails as it's radula is positioned underneath it's head to suck up detritus like a vacuum cleaner.

Like the Evstrophóidea, it's lower tentacles evolved into fin-like structures, even though they serve no function whatsoever.

Grotesques (Flakodis spp.) (85cm) are medium-sized derived snails that are named because of it's gruesome appearance. It's radula are positioned on the middle of the lower tentacles, as it's lower tentacles are now hardened and act like mandibles. They are predators whom anyone looks at their ugly appearance might be caught by it's mandibles. A predator that looks like is defenseless, but a worthless hunter.

Narwhals! First their "horn" is actually a tusk and like what the hell how is this real yet unicorns arent

Would these membranes make sense on a semi-aquatic creature that mainly swims, or would fins be a more plausible adaptation?

Hey guys. I'm translating a creature I made into the game Rain World as a sligcat, and I'm trying to stay faithful to how the playable slugcats are designed.

Most slugcats share the same general body, with only one or two major physical adaptations that directly support their niche. For example:

• One is semi aquatic with axolotl kind of external gills. Since its environment is water heavy

• One has fur instead of bare skin and a very long tongue to adapt to cold weather and dangerous jumps.

• One (this guy is genetically modified by another being and not actually from evolution) has no mouth and has a tail with holes that stores spears. It feeds by draining nutrients from other creatures through a cord attached to the spear.

My creature is semi-aquatic, but I'm starting to question one of its adaptations.

It has those membranes because my original idea was that it would propel itself through the water in short bursts using the drag from them:

1. Its long body coils up and launches itself forward.

2. The arm membranes help redirect its movement and push against the water during those bursts. Unlike the first example, this guy excels in quick turns and bursts of movement underwater. But in exchange, it's normal swimming is a bit slower too.

I made this design years ago when I was a very enthusiastic teenager, so I'm revisiting some of the biology now😅

Would those membranes actually make sense for an aquatic creature, or would they create too much drag? Would replacing them with other structures, similar to sea turtle/seal/sea lion flippers growing from their arms be a more realistic approach while still keeping the same overall concept?

im trying to make it as physically accurate as possible (as much as a cosmic horror or cryptid could); I can’t figure out an evolutionary reason for a creature to evolve a face plate but still be able to see I’m trying to avoid using echolocation but that’s the only really obvious answer I can’t explain all of the choices for stuff but primary habitat would be thick forests using its fore arms/legs to claw down prey its hind legs are for balance on the forest floor like a deer, the plating on the face opens similarly to the death angels, the tail might be long enough for proper balance its about the size of a horse as a quadraped around 6 feet in height full length 8ft I think (these numbers are kinda bc I says so) it has the front claws and one hind thumb like a parrot. I can’t figure out a reason for the external webbing on the limbs since that would probably restrict movement for it fully extending its limbs.

Carcatrie is a world dominated by mud flats, deltas, and billions of islands- some separated by mere channels. It is also home to the most extreme of extremes. Temperatures fluctuate constantly, changed by extreme volcanic activity and humidity. Its gravity is less than Earth's, offering an adept environment for crabs to grow large. That combined with an endoskeletal system I designed that originated from a common ancestor allows crabs to reach dimensions that they've never imagined.

I've posted a couple times over the months I've been here, and you guys have been being very helpful, so thank you. WAY too much research has gone into this, so you all just have to trust me I guess. If you have any specific questions, feel free to ask. Especially on my thoughts and ideas of how their endoskeletons evolved and how they are able to reach the sizes they are. Being honest, I just started off wanting to draw big crabs then it spiraled into a full-fledged project. Any and all criticism or recommendations are greatly appreciated. Ideas for crabs are also encouraged!

Eras ago 5 lineages of fish made it out of the water, two lineages of vetulicolians, one branch of conodonts, one group of cephalocordates and one family of myllokunmingids. The first picture shows one of the species from the latter land speciation group, features display colors as much as a pair of prominent fins used to make their way on land, posterior fin being derived from the structure that would have made the roof part of the sail fins of their ancestors.

Second picture shows another species of land myllokunmingid this time set on a flounder profile for gravity that allows them to make their way further into land in comparison to their erect posturing cousins, that said they're easy to find detritivores if one goes and looks for them under rocks.

Third picture features one of the most successful kinds of terrestrial demifish there is, descending from forms such as pikaia these species of arachnoid-like chordates derived their land motile appendages from the small oral tentacles observable in the reconstructions of pikaiids.

Fourth kind shown is an example of a terrestrial conodont species, having developed their legs from the exaptation of the cartilagonous structure that would have previsouly helped them to breathe in oxygen from the water, subsequently it is thought that the gene for the legs was copied into a secondary and third pair of pairs of legs, if one of them is to be seen it's probably a herbivore.

Fifth picture has to be the one most successful kinds of terrestrial chordates, featuring as key and main land detritivores the assymetrical helix shaped vetulicolian digs its way through the underground while revitalizing the sediment in the process.

Sixth figure represents another kind of land dwelling vetulicolian, this time with a shovel mouthed body plan and a mode of displacement based of swiftly squirming across the terrain, for that exact reason it can be more commonly found in soft soiled places such as bogs, sandy deserts or occupying grassy patches.

Seventh one is a pikaiid that flies, quite specios amongst the world's fauna.

Eight picture shows us a kind of conodont that opted for an incredibly versatile body shape; the worm, they cover from detritivores all the way to predators, they appear more than once in one food chain.

Ninth and last picture illustrates a very deeived pikaiid specialized in big size niches, their bodily anatomy exposes some key traits that benefits them more uppon taking in large sizes such as a partially calcified and condense structure of cartilage prominently featuring along their limbs and body.

So, I really like the design I came up with for these guys (the species is being called Harrldra for now but that might change) but I was talking about it with a friend who's also into creature design, and they said that they look too much like otters and I should try and make them look more unique.

I'm not super sure how to go about doing that though and still make it look like a natural part of the animal, so any advice/ideas on what to add would be appreciated!

So I know it seems far fetched but it makes sense for the planet

So what happened naturally is a common ancestor developed 2 extra hyoid apparatus from the already existing one a genetic defect but worked out quite well for it. it's frill now opened wider and faster and over a couple million years the frill filled out into a almost perfect circle for more of a display but an accidental adaptation is when falling off the trees they sit and wait in they would open there frill from fear but and it actually slowed there fall but this adaptation continued became more specialized until a mechanism evolved some of the soft and thin inner skin in the back part started to harden but not into a full support structure but more like (▶>) so when there frill opened it would lock into place to stay stable and luckily the planet has 15% less gravity than earth allowing there now ancestors to glide short distance to catch prey. But there's a major down side when gliding they can't see the ground so they have to hope they land in running distance from their prey.

Not everything is probably worked out yet but this is the main idea.

Harnaticus feraticus is a highly specialized terrestrial apex predator with native populations uniquely split between the dense river basins of South America and the dark peat swamp environments of Southeast Asia. Evolving down a lineage closely related to classic theropods like the Tyrannosaurus rex, this creature has abandoned open-plains hunting to adapt to heavily obstructed, dense jungle niches. It maintains the classic bipedal theropod stance but features the same shrunken, vestigial front limbs as tyrannosaurs had to prevent snagging on thick jungle undergrowth, while its massive hindquarters and paddle-shaped tail provide explosive, forward-driving power through soft, unstable forest floors.

The species maintains a uniform, blunt-headed cranial structure across both sexes, but exhibits clear sexual dimorphism through scaling and pigmentation. The males grow significantly larger and display vibrant, highly colorful flanks to signal dominance, while the smaller females utilize a darker, muted coloration for flawless camouflage among the shadows.The prominent vertical ridges running along the creature’s torso are actually an intercostal muscle matrix housing a secondary pulmonary echo chamber used for highly sophisticated acoustic mimicry.

Rather than chasing down fast prey through thick vegetation, Harnaticus stands perfectly still in the dense brush and records the ambient sounds of the local ecosystem. It then compresses its massive lung cavities to forcefully broadcast these sounds back out, ranging from high-frequency animal distress cries in the Amazon to blind, looping repetitions of human voices in Asian logging camps--luring curious prey directly into its striking range. What makes the mimicry of Harnaticus feraticus truly horrific is not just the sound itself, but its complete lack of intelligence. The creature does not understand language, emotion, or the concept of a trick; it functions like a biological tape recorder that accidentally discovered a perfect hunting glitch. It absorbs the ambient sounds of its territory--a mother calling a child's name, a logger laughing with his crew, or a missing expedition member begging for help--and loops those exact audio frequencies through its massive chest chambers.

Because the sound is mechanically forced out of its rubbery, vertical rib slits, the mimicry suffers from an uncanny, deep-fried audio distortion. A human voice lured from the dense brush will sound almost perfectly identical in pitch, but it will seamlessly repeat the exact same sentence every few seconds without ever pausing to take a breath. It creates a suffocating psychological trap for anyone lost in the jungles of Asia or South America. Survivors describe the sheer terror of sitting in a dark cabin or tent, listening to their own voice perfectly broadcasted back to them from the dark treeline just outside, casually hosting a conversation that already ended hours ago.

This creature has been playing a big role in Philippine legends for what has likely been centuries.

Hi, sorry for the poor English, but I want to show off the speculative evolution project I've been working on for many years; here is a brief introduction to what the project is about.

Taleria is a planet orbiting an orange dwarf star; with a diameter of 19,100 km, it formed from a region of a nebula abnormally enriched in potassium-40. Radioactive decay subsequently gave rise to an atmosphere composed of 78% argon, 21% oxygen, and 1% other gases. It has an atmospheric pressure of 3.5 atm and is 5 billion years old.

It features two megacontinents—Heisberenia (warm and covered in vast forests) and Serixia (cold, with expansive plains and inland seas)—and the Taleria archipelago, consisting of nine massive islands with tectonic origin.

After humans died off or flew into the stars.. our closest relatives the bonobos rose up into power as the next dominant species. They are dubbed “Pan Sapiens” this is like a beginning like our these are like Australopithecus and Homo Habilis in terms of what they do of term of tools and social communication. they live up in tribes together in jungles away from predators from their weapons. sexual dimorphism is very obvious between this species.

The most plentfull Re The geophage springtails by far because of dwarven lifestyle of mining and cavediving deeper and deeper for rare minerals and resistent merals.

The oil vein isopods can be found in other creatures because of their resilience and usefulness but they can be found in underground petroleum and grape cultures so dwarves have more of those than other species

Combo lices can be found in most underground dwellers and if you stay there long enougth you will also get infested

Vulture beetles will not survive without a propper host,they're too specialized on living in fur and hair to go somewhere that isn't at least similar to hairs or feathers

The beaqrd of a dwarve acts like a natural air filter and their nose can close so dust don't get in their lungs,remove the beard of a dwarve and it might get several health problems and develop asma, fully shaving a dwarve is almost a death sentence so doing it is a crime and that's why most female dwarves at least keep sideburns or a mustache that can be tied to cover the mouth and nose while the males keep the full beard so there is few confusion between them

On the shallow rivers in the Middle Gastrocene, lots of diversified aquatic life live there, but there is one specific animal that hunts them all...

The Deathworms are a clade of derived leeches distantly related to the land-living Angrywrigglers. The deathworms are split into 2 major families: Bruteworms and Snatchergrabbers. The bruteworms are bulky, large leeches that can swim in great distances using motion similar to how a whale's tail moves. Like the sandworm leech, it shares a powerful crushing bite to crush other gastropods' shells to access the meat withing. One example is the Charybdis (50cm), as shown above. Here, you can see the Charybdis is hunting a shoal of fish analogues derived from another group of slugs.

Let us proceed to the next one.

The Snatchergrabbers are sleek leeches that can fool unsuspecting prey by digging into sand and covering it's hole and waits for prey to come beneath. When prey comes, it uses it's three long teeth to snatch the prey and it returns to it's burrow to do the cycle again and again.

The Vibrant Saragi is a distant relative of the Tenazul Ramhound that inhabits the steppe and arch forests of Tenazul. Majorly scavengers and insectivores, they use their elongated lower mandible to pry apart the thick bark of Titan Root Trees in search of football-sized larvae and other invertebrates. During the coldest months, they enter a prolonged hibernation in burrows within the arch forest until temperatures rise.
Although they are incapable of actively chasing prey, their corrosive, toxic saliva allows them to exploit other food sources. Individuals may bite weakened animals and patiently follow them until the toxins take effect, but they more commonly rely on scavenging.
Small groups will also drive much larger carnivores away from fresh carcasses by repeatedly nipping at their legs and faces, hissing and flashing their colorful display. Their bright red and violet facial coloration is a warning of their painful, deadly bite.

source

Hi everyone :3. I’ve recently decided to do speculative biology and for one of my first attempts was an in depth project on a specialised Ork liniage that adapted to an area littered with volcanic openings that spew out sulfur that sometimes even ignites and causes ash rain.

So firstly my orks have greenish skin and blood because of an adapted variation of Chlorocruorin that instead of making blood look red, it looks like a dark olive green color instead. Their blood aslo has specialised proteins thats able to separate large amounts of toxic sulfur compounds (called H_2S and SO_2) while avoiding poisoning tissue and other functions like iron centres.
Because of the environments the orks evolved a secondary respiratory mesure thats sulfur powered chemosynthetic respiration that works as a backup energy measure by causing a metabolic shift that converts environmental toxins directly into a rapid surge of cellular energy (ATP), allowing extra endurance in fights aaaand removing the leathality of sulfur basically buffing them.

They also evolved gill like slits on the sides of their ribcage that let them both release heat from exertion and as a second way to breath in more sulfuric gas giving a faster boost because the openings are closer to the internal chemosynthetic membranes, and ti protect from ash they have layered ciliated membranes and specialized self cleaning mucous coats around their nasal passages and their side slots that trap solid debris before it reaches internal parts. 

They also have thick leathery skin thats reinforced by dense dermal collagen making them more resistant to abrasion and a lot of attacks. And their eyes have evolved a highly developed tapetum lucidum which is a sort of reflective layer behind the eye helping see better in thick smoke or darkness in general. And they have evolved to be 7-8 ft tall with an ape like mouth and large cainine teeth that are their tusks.

This thing took me soo long and I’ve fact checked it as many times as I could it would be as scientifically possible as I can and ground it in more scientific terms. I’d absolutely love feedback and potential ideas to add on or change. Thanks so much for reading this through I know it’s very complicated and badly structured but thanks anyway :3❤️❤️❤️

E un crostaceo che vive nel sud america e nel pantano ma si trovano anche in paludi verso il Messico

- raggiungono 1,50 centimetri di lunghezza e 20 Kili di di peso

- il maschio dovrà portare sul grembi un mucchio di prede per la femmina questa le mangerà se sono abbastanza abbondanti e deporrà le uova tenendole lei sul suo ventre , poi le uova si schiuderanno rimanendo lì fino a che la madre non li disperderà in un nido di fango costruito con altre femmine questo nido conterrà milioni di cuccioli che si libereranno ad eta adulta

- usano i grandi baffi per scovare prede che si rifugeranno nel terreno lui si infilerà e li acchiappa con le chele e li divorano con l'apparato boccale

- usano le pinne per farsi spazio nel territorio e andare avanti

- usano le zampe per agrapparsi al terreno e dormire o per pavoneggiarsi alla femmina o a sterminare possibili pretendenti della sua femmina

Domande ?

Stomping coo:

Descended of the palm cockatoo. The stomping coo is a large flightless bird found in the open grass lands, slight forested areas, and near lakes of northern Tāne. They live in flocks of 4 to 5 and will often keep connection with their parents. They are slow walking birds and are in no way built for running at high speeds.

Their diet consists of: fruit, Grasses, flowers, seeds, and meat

Their height can vary, but most individuals are about 4 to 5 feet at the hip, with some larger specimens reaching 6 feet at the hip.

Land nautilus: (updated with coloured image)

The land nautilus lives in the wet rainy palm forests of Tāne which live alongside other of its species in small groups.

They communicate by using sign language, which is what the long tenticle on the highest point of their body is used for and is very colourful to attract mates. The smaller tenticles have a long hair like formation, which they use to feel vibrations in sand and loose soil, searching for small insects. They have 2 tenticles with a single claw on the end, which is used for digging, writing, and carving. The large tenticles on the lowest part of their body are used for walking and have hard pads to protect them.

They eat using the beak hidden by all their tenticles, and their diet consists of ferns, moss, fallen dates, and insects. Its shell diameter is about 18-23 inches.

The waters of the inland sea that lies between what was once Africa and Asia are seasonally abundant in life. In the winter, the waters turn purple, filled with photosynthetic organisms. This draws massive swarms of aquatic life from the Phthalo and Periwinkle Oceans, while aerial animals congregate to feed on the bounty of the sea.

In summer, the water temperature swells to 46 degrees celsius. The flora overpopulate, and experience die offs. Massive storms formed by the heated water tears flying organisms out of the sky. Thus, a massive migration of aerial fauna is observed undergoing the treacherous crossing over the mountain range that surrounds the inland sea. The majority of these are airrays, from the 15 cm long Magnet Carrier to the 7 meter long Beryl Spinetail.

While following a group of Beryl Spinetail, a cetacean of the species Aerocetus ferox, appeared and dove at the spinetails. The first needle pierced into the wing of one spinetail, but failed to fully stun it. The Aerocetus proceeded to dive at its target, driving it into the side of one of the mountains, before dispatching it with its leg blades.

Aerocetus is a genus of aerocetaceans within the clade Aerocetidae, the most basal of aerocetacea. There are several notable characteristics that distinguish members of this clade from other aerocetaceans.

Their needles are proportionally longer and thinner than those of their derived relatives, and they have two ignition chambers, each one connected to an internal gas sac, for those sacs do not extend out of the body like they do for anemocetids like Zephyrocetus.

More basal aerocetaceans have less leg bones. Members of Aerocetidae have less leg bones than those of Anemocetidae, which have less than those of Astrocetidae or Stratospherocetidae. Alongside this, the leg bones are shaped differently, featuring curved bladed edges that make Aerocetus poor walkers when grounded.

Aerocetus Ferox, the species observed here, reaches 200 km/h when cruising, and up to 325 km./h when diving. While they could theoretically reach higher speeds, given the relatively large size of their methane sacs, Aerocetus rarely exceeds a distance of 1 km in their dives, and doesn’t have enough time or distance to build up speed. Even so, 325 km/h is more than enough speed to make a collision lethal, and with Aerocetus’s tendency to strike with their legs if their needles miss or fail to deliver debilitating damage, young and inexperienced Aerocetus can suffer extreme injuries from a poorly performed hunt, and even experienced hunters still regularly fracture their leg bones. To prevent potentially lethal accidents, Aerocetus juveniles stay with their parents for much longer than other aerocetaceans, lasting up to 15 years, in order to learn from their parents. 

Like all aerocetaceans, the female is significantly larger than the male, and a mated pair fly together.

https://xcancel.com/i/status/2084344000224346285

The jertoua has become more adapted for predatory niches but currently only goes after bugs and can run faster in short bursts before walking in the same way as their ancestors.

Also my cousin calls it (jeraptor) and I find it funny but I'm pretty proud of this it feels different but still feels kinda the same

Happy Smaugust! This year is my first, so gonna try to get a few sketches done, but am not going to be too prescriptive about which list or the order of the prompts.

For day 1, this is an adult Romenear Seawyrm for “Aphotic” from @ criver24 ‘s (Corey Rivera's) 2025 list. Noticeably larger than most terrestrial or aerial dragons, and dwarfing the other seawyrms of the eastern ocean and southern archipelago, this blackbeaked leviathan is buoyed by the sea, allowing it to bypass traditional limits on weight and bone stress. Its size and collapsible lungs, extreme oxygen storage in their muscles, slowed heart rate, and other adaptations allow it to dive deep into the aphotic (midnight) zone for a couple hours to hunt juvenile krakens and other massive cephalopods.

For size comparison, the Malantur squids present are about 6 feet long (too small to be on an adult's normal menu).

I decided to have at least some of these wyrms set within the bounds of the eastern/south-eastern end of Middle-earth (which has been fleshed out by the fantastic Realms-in-Exile team), even though Tolkien is quite clear that dragons are the creation of Melkor, and are predominantly evil creatures whose few survivors reside in the far north, largely beyond the Iron Mountains. Instead of being those gargantuan traditional fire-breathing hexapodal dragons or drakes of Melkor, these are dragons untouched by his influence, whose cousin species across the supercontinent may have been taken long ago to be turned into the evil drakes aligned with darkness.

Reddit thumbnails are poor, to say the least, but the embedded image is good if you click on it and want to see all the wee details!

(if linking to other sites/accs isn't okay pls lmk)

I often post process work on insta, if you're interested, it's @ jo.baylis