Okay I decided to lump dragons, gargoyles and griffins all together. This should be 3 parts, so heres the first. The group of animals we will be keeping track of will be called fantaforms. So right, dragons require 100s of millions of years to evolve and therefore must have popped up in the Jurassic. And by the way I’ll be accepting the underdark as fact. Thankfully I don’t know any hollow earthers, and to any who are reading this: this isn’t an endorsement. Our dragons (and a bunch of other stuff with similar morphology) will have evolved from gliding, tree dwelling, Antarctic lizards that have the same barfing defence as komodos and vultures. They will have the unique trait of split limbs. Their first two digits of the forelimbs will be elongated to walk, and the other two will be even more elongated to glide, and when the forests they live in disappear, to fly. They will split into two lineages, those that compete with early birds and Pterosaurs for the skies and those that mostly fly to migrate and escape, hunting on the ground. The first group we will call aquads and the second we will call the orthanosaurs. The aquads will lose one of their walking fingers and the other will be incorporated into the wing for the support required to fly long distances or quickly take off, while the orthanosaurs will shorten their arm bones and elongate their fingers, further separating the limbs for greater land speed.
One group of the aquads will find their way into the underdark and gain shortened limbs to cope with the required agility to hide in caves. Their legs will gain patagiums so as to not lose their flying skill with the reduction of their wings. So as to not go into torpor in the cold of the underdark they will gain mesothermy and gigantothermy, growing in size to fill the niche of scavenger, as Pterosaurs and birds rely to much on their vision to live in the darkened underdark, so these aquads, which we will call basiloforms, will become largest flying animals around. Speaking of senses, the basiloforms need a way to sense their environment, and will gain whiskers to sense prey and wind currents. They will still have a good sense of sight adapted to see static objects in low light.
A single species of aquads will undergo island gigantism and exclude the island of Cretacius Sri Lanka from Pterosaurs, reaching 20 foot wingspans and diversifying to fill the niches of scavenger, fisher, air apex and even land predator. This group, now a genus, will be known as the protowyvroforms.
A group of orthanosaurs known as the pterotheres will adapt to the coldest climes of the early cretaceous with hollow fibers and endothermy. They will barf up steaming oil for their mates to smell as part of their mating ritual. The oil and temperatures required are calorie intensive, and are a good sign that a prospective mate is eating well. The females will smell the mating fluid (as it is known) of any males that’s territory borders hers, choosing anywhere from zero to 4 males depending on the quantity of the fluid and how much the “taste” of the female matches the perceived eating history of the male, gathered by smelling his fluid. The females use their fluid to feed their young, as they have no need to display. They must shed constantly on their nests so they do not cool off from the directions the female cannot cover, selecting them for more insulating integument. The females will evolve setae lining their quills (the technical term for their fur-like covering) that stick to other setae, drastically increasing it’s insulation effectiveness after shedding. The pterothere males will also have these barbs due to a lack of dimorphism, and may broaden the quills on their wings to use them for intimidation. To fly with these large quills the pterotheres will shorten their arm bones into non-existence, replacing them with elongated hand bones. This effectively separates each forelimb into forelimbs, this allows for greater speed on land and in the sky. To optimize for this speed they will stiffen their wing quills to protect them from damage and make them frost resistant, and place their legs directly underneath them. These highly derived pterotheres will be called gryifics. Some of the less derived forms will be forced into the underdark due to competition from the newly diversified birds of the middle cretaceous and their derived cousins. They will gain tough skin and large fang-like teeth to fight, and their quills will re-merge into the skin to harden it further. Their powerful defence and offence will allow them to hunt like an eagle or vulture, forcing the basiloforms into the niches of hawks, bats, falcons and non-macropredatory birds. For senses they will gain better night vision and external ears. Their forelimbs will split convergently with their cousins to hunt better on land and to support a fully ossified skeleton. These underdark hunters will be called daemoforms.
In response to the daemoforms the basiloforms will have to gain the firepower to defend their kills, and exploit their mobility. One clade will centralize on the former requirement. Their barf defence will change composition, now being made of a steaming hot alkaline solution that burns uncovered skin, made from salt, bile, and in insectivorous species, insect toxins. The salt will be sourced from salt licks, found in caves with smell and magnetoreception. They will also gain mobility. Their wrist bones will grow into pseudotoes with claw-like scales for claws on their forelimbs. Their rear limbs will simply partially lose their flight purpose. The forewings and the leftovers of the hindwings will merge into folding structures that allow these critters, known as lòngoforms, to work like a scaled up version of a flying snake. This will give them stupid amounts of endurance when flying on underground windcurrents and good manuvoribly otherwise, but pitiful speed. Given These restrictions and strengths they play to their strengths by flying great distances and landing to fight tooth, claw and deathbarf over carcasses. This puts them in direct competition with daemoforms. This will be important later. Other clades evolved different strategies but they all die soon so I won’t even detail them.
But what has been going on in Antarctica this whole time? Well by the early cretaceous the aquads had been pressed to regional extinction by competition from a new clade of orthanosaurs. They will be known as the drakes, and will be giants. Their arms will split like the pterotheres, but differently. They will keep their arm bones, but they will split. This gives them the ability to run on land and fly with agility. They will gain special bone morphology to fly long distances with their small number of wing bones. This also give them strong legs, which they will use to run better. To augment this their wrist bones will extend into pseudodidgits. They will now have four digits on their forelegs, and three on their hindlegs. As with the daemoforms they will use scales as claws, which are useful for traction. They will develop huge shoulders bones to do what the breastbone of birds does, support their wing musculature. To defend their kills from theropod dinosaurs, and to make those kills in the first place, they will gain strong, crocodile shaped, jaws and modify their barf. They will develop secondary and separate bile glands and gallbladders to supply the barf. They will also produce something other than bile. The glands will produce fatty acids that saturate in the gallbladder with fiber that these drakes get from plants they eat for vitamins and sugars. The interior of the gallbladder is anoxic, presenting the perfect environment for fermentation. A mixture of methanol and lactic acid is what is barfed up, and disperses into the air, making a smelly and intoxicating vapor used to chase away rivals. They patrol large distances to hunt, sensing earths magnetic field to navigate, and migrating to India in the winter to stay away from the cold and fight Sri Lankan wyvrens for sport. They are the most intelligent orthanosaurs so far followed by gryifics.
Next up the K-T extinction.
Edit: I just moved this into Other Creatively cause i can.