Squamaves

Introduction
The last scattered remanants of a once proud and mighty empire that ruled every corner of the planet. Once one of the greatest dynasties the world has ever seen, stretching to every continent, every sea, every habitat. Probably once present in tens of thousands upon thousands of species now reduced to a few hundred species at the most. Although still found across all continents, they are a pathetic portion of a once great clade. The few remaining groups are so far derived that it would be difficult to see that they are one and the same. Small scuttling creatures not unlike some crustaceans in appearance far removed from scaly skin-winged animals are among the few clades that still walk the Earth.

History
Molecular clock studies along with fossil evidence suggests that the earliest members of the branch leading to the neobirds appeared approximately 600 million years when they split off from the ancestors of their closest living relatives the molegators and billodiles. Fossils numerous in Notoia from the era before the Cenozoic (otherwise scarce elsewhere), show an epic lineage; for over 165 million years, these ancestral creatures were the rulers of Earth; their reign was absolute, skeletons of behemoths easily over 18 metres and 20 tonnes in weight are known, although fragmentary material suggests of colossi over 30 metres and 90 tonnes in weight, easily larger than any other land animal known to have existed. Around 490 million years ago the first recognizable remains of the proto-squamaves appeared, although they were still quite different from even the most modern forms. Around 416 MYA an extraterrestrial object approximately 10km wide struck the Earth, the exact location is unknown. Every clade not closely related to these proto-squamaves were completely wiped out. These proto-squamaves, referred to as the paraphyletic group 'aves', became the dominant flying vertebrate clade following the end of the Mesozoic, although another group of flying vertebrates did appear approximately 390 MYA; they were a group of mammals that had skin stretched across fingers similar to modern wingfrogs (although on their hands rather than their legs). This went on until around 340 MYA, when climate change and volcanic eruptions managed to tip the scales in favour of these skin-winged mammals (known as chiropterans). These mammals quickly spread into the domain of the avians, outcompeting them and evolving into massive and diverse forms. It seemed that the chiropterans were on their way to replacing the avians as the rulers of the sky, but it was not to be.

290 million years ago, the Mediterranean Traps erupted in a massive scale over many tens of thousands of years, wiping out around 80% of all life and ending the age of mammals. Among the many groups that perished were the flying mammals, ended in their prime. The avians managed to survive in limited diversity; only three orders are believed to have made it past the Cenozoic (the extinct Passeriformes and Anseriformes, plus the ancestral group of which the squamavians descend, the Galliformes). For the avians, their time was coming to a close; to further this fact, a new group of flying animals descended from scincids (along with an early group of volant snakes) arrived on the scene around 260MYA. The passerines faded into history around 150MYA and the last of the anseriformes were wiped out at the end of the Stiliozoic, but they're not particularly important to this essay. By the half point of the Stiliozoic, the birds had all but surrendered the skies to the squamatan rulers; most forms were now ground animals which could dream of once again taking to the skies, but there was one species that could do more than simply imagine flight once more. A mammal-like species that had lost the feathers necessary, but still retained the wing strength and musculation needed for flying.

Pictured is a example of an animal close to the ancestry of the squamavians, Nyctibioides archaeus which is currently the closest known relative of the neobirds. Although definitely flightless, it still retains a full coat of feathers and large arms; its hypothesized that it used its previously wings to dig through foliage and leaf litter for food or/and to defend itself. It seems that while flightless, the ancestor of the neobirds still retained attributes that would be preferable for flying. The ancestor of the squamavians was most likely an arboreal animal that eventually redeveloped flight as the forests it lived in began to disappear during the Allogene and it flew to reach the now much further individual trees. The presence of the flying scincids severed limited the diversity of the first neobirds however, and the appearance of the first pirgs obviously didn't help things. It was only the complete extinction of their squamatan competition that allowed them to diversify somewhat.

Even after the end of the Stiliozoic, their diversity of the neobirds remained rather small, as they still retained competiton in the surviving pirgs and newly emerged wingfrogs, as well having much if not almost all their species wiped out at the end of the Summocene. They'd have a little more luck down on the ground, having once again evolved flightlessness, but otherwise they'd almost completely been outcompeted by the volant mammals and anurans; only a few dozen flying species still survive today.

Description
Having over half a billion years of evolutionary history behind them, the neobirds show it through their incredibly derived anatomy. All neobirds lack lips and teeth, instead having hard beaks; as well, all lack prehensile forelimbs and every species are bipedal to an extent. Although ancient proto-neobirds flew with elongated structures derived from their integument, modern flying species all fly with skin stretched from their fingertip to their hip or knee. Their feet bear only three toes and their hands only bare one "finger", as such, manipulation of objects is done primarily using their mouthparts, with some clades developing a highly dexterous tongue in compensation for lack of hands. Well preserved fossils of proto-neobirds show of extensive coats of feathers that probably coated the entire animals; in comparison, the coat of modern neobirds is quite sparse. They usually only having a light covering for insulation and it may be difficult to see in most cases unless up close; in scuttlers it has developed into a heavy armour shell. All neobirds lay hard-shelled eggs and almost always pour great care into their offspring.

Because they have the gift of flight, they range far across every continent, even Arabia.Their ancient lineage can be seen in the highly derived forms that have developed that range from tall stick-legged waders to heavily armoured scavengers. Around 420 surviving species are known, the majority of them being flightless animals. It seems that while flightlessness developed many times over in extinct proto-squamavians, it only developed once in neobirds, although if it has anything to do with the different structure of the wings or it's simply a limited sample size (because of the relatively small number of living neobird species) is unknown. Neobirds are usually smallish animals, and the largest species are marine animals that may reach 3 metres in length; flying species usually average around 12 centimetres in length with a 20 centimetre wingspan, with the biggest species having a wingspan of around 2 metres. Although they have a relatively low species count, they are quite diverse for a clade in its last dynasty; aquatic, volant, fossorial, wading, seed-eating, predatory and grazing species are known. Neobirds usually make up only a small portion of the biomass but there are very few habitats that do not have at least a few species of them.

Diversity
Although having an unimaginably ancient and complicated history, it's clear that it'll not be long before the last of this great lineage will disappear into the fossil record, perhaps in less than 100 million years. Of the tens of thousands species that certainly ruled the skies long ago, only a few hundred still live on. Despite all this, neobirds have managed to take hold in quite a few shapes and lifestyles, with forms ranging from almost insect-like creatures to huge filter-feeders that are found across almost every landmass and habitat, primarily due to that skill that very few animals have ever picked up: flight.