A Brief History

The small continent of Unciolis is the most isolated of all Apterra's major landmasses. It is by far the largest stretch of land that's never been connected to Panapterra and, consequently, to the terrestrial life-forms that originated there. Over the course of life's ten-million-year history on the planet, tetrapods have reached its shores thrice, essentially turning Unciolis into a miniature seeded world within a seeded world. Of course, its waterways are significantly more diverse, with the first fish colonizing its lakes and rivers less than half a million years post-abandonment. Soon, entire lineages had their evolutionary tragectories changed due to its influence, as was the case with the stoutlings. By the beginning of the Arthrocene, every major group of fish had representatives in or around Unciolis's waters. The situation is similar for its plant community, as most Apterran grasses have some mechanism of dispersing across long distances. The only exception, until recently, was the woodlouse-grass clade, none of which existed here until less than a million years ago. They remain limited in range on this continent, as their arboreal isopod symbiotes have still yet to make the journey. On the other hand, a wide variety of solitary woodlice have arrived over the millennia, as have a number of mosquitoes, both flying and neotenic. Despite this, land vertebrate diversity is still low and will probably remain that way for many epochs to come. What follows is an overview of all such inhabitants, including both permanent residents and species that only occasionally pay a visit.

The first of the former group, a subspecies of transcontinental seawi, arrived here near the end of the Muricene. Though it was alone on a continent seemingly free for the taking, it found difficulty adapting away from the ocean, and its descendants typically remained near the coasts and rivers where fish could be found. It was too specialized to make the switch to the abundant plant-based food sources of Unciolis, too slow on land to catch flying insects, and too large to survive off any but the biggest isopods. Still, after weathering the Ice Age by sheltering on the last ice-free northern shorelines, it diverged into a handful of species comprising the genus Abscondinatator. This clade thrived during the first two million years of the Arthrocene, feeding on fish, tailtube worms, and aquatic woodlice in both fresh and saltwater ecosystems. However, new competition would soon bring this age of terrestrial transcontinentals to an end.

Just after five million years post-abandonment, the tail end of the Early Arthrocene was marked by the arrival of a different seawi species, this time belonging to the seacock subfamily. Seacocks, being typically short-distance swimmers, don't have the ability to cross from Panapterra to Unciolis intentionally, but a freak tropical storm caused by Apterra's warming climate occasionally drags a wayward individual over the wide Interthalassic gap. In this case, an entire flock was transported, resulting in a stable breeding population establishing itself. These were adaptable birds not overly devoted to any one diet, and within a few tens of thousands of years - an evolutionary blink of an eye - they'd radiated into many distinct niches. Some became fast-moving herbivores, while others reached megafaunal sizes, with many species spreading deep into the continental interior where their relatives had never been able to conquer. The transcontinental lineage entered into a gradual decline as even its fishing niche was slowly overtaken by seacocks, and there was soon only one left: a large, powerfully built species capable of subsisting on carrion when necessary, allowing it to avoid competition with the new influx of fellow secondary consumers. But even this survival strategy was not to last.

Half a million years ago, another seacock made the trip from southern Abeli to the Unciolan coast. This one was a close cousin of the gannetgrouse and shared that genus's distinctive gular pouches, which in both groups serve as a reserve of immune cells, bolstering their owners' already impressive avian immune systems. Both white blood cells and disease-killing microbes are stored in these sacs, ensuring the bird is always prepared to mount an attack against any pathogen it encounters. This seacock species did not, however, possess the second set of cheek pouches that in gannetgrouse have a similar storage function for the gut microbes that allow them to digest tough plant matter. Thus, it was restricted to a primarily meat-based diet. Better able to resist infection than the established transcontinental scavengers, it quickly outcompeted them, becoming the continent's primary corpse disposal service.

Current Residents

In the modern day, this kiwi is known as the Carrion Seacock (Guttutela aplumops). Though it is the only member of its genus, at least ten subspecies exist across Unciolis and its surrounding islands, occupying every habitat from the tideslopes to the temperate rainforests to the cold taiga in the heart of the southern landmass. Meanwhile, the last remaining Unciolan transcontinental kiwis, ousted from their role in the ecosystem for a second time, moved up the trophic pyramid to survive. With an abundance of large plant-eaters, it was only a matter of time before an apex predator emerged. This hunter, called the Sirenfowl (Ultimovenator diploreprobatus), uses every feature of its ancestry to dispatch its victims. It is an ambush predator, waiting patiently for hours or even days at a time. This is an exaptation of the extremely patient demeanor it developed as a shore-based fishing species. When it finally sees an opportunity, it lashes out, wrapping its deep, rectangular bill around its target's neck. Though its jaws are built to hold onto struggling prey, the sirenfowl can't exert enough force to strangle a seacock or snap its neck, so it must rely on another method to finish the kill. Its strong legs drag it and the other bird backward towards a stream or pond it previously scoped out, pulling both predator and prey beneath the surface. Then it's a contest to see who can hold their breath longest, one which the sirenfowl nearly always wins because of its heritage as a deep-diving, big-lunged oceangoer. 

Of the dozens of species the Ultimovenator regularly feeds on, all belong to the second-arriving clade, as the carrion seacock's own eating habits make it too germ-ridden to risk consuming. In the five million years since they came here, this more diverse seacock clade has branched off in directions unseen in any other Apterran bird group. On the other hand, one of them is perhaps the most "normal" kiwi on the planet. The most basal of this tribe - the Humulapterini - is the Apterrunner (Agilapteryx), a generalist that never exceeds two or three kilos in mass. The twenty-plus apterrunner species are by far the most numerous birds on Unciolis. Without any rats on the continent, this genus was able to reclaim the niche that kiwis historically held in their original home of Aotearoa. Foraging methodically through the woodlands, a flock of apterrunners turns over rocks and leaf litter in search of seeds, bugs, and other small scraps of edible material. When danger strikes, their long legs can propel them up to forty kilometers per hour, darting into a burrow or up a tree until the coast is clear. Still, not all escape successfully, and the unlucky ones become a welcome snack to their sirenfowl overlords.

Just as Agilapteryx is the sister group to all other Humulapterins, the next genus is the closest relative of the remainder of the clade. This is the Wrenchbill (Brevimaxillapteryx), a low-to-middle-browser with a distinctive underbite. This trait allows it to wedge its jaw into logs, under large stones, and anywhere else that might contain hidden food. It is also strong enough to break medium-sized tree limbs, after which it can more easily strip off the leaves and seeds if it so chooses. Just as often, though, it may simply eat the branch too, as palm-grass wood is not as difficult to digest as that of Earth trees. A handful of wrenchbill species exist all across Unciolis, ranging from 50 to 250 kilograms and with the largest individuals standing more than 170 centimeters at the shoulder. This genus thus lacks the speed of the apterrunner, so it must rely on its size and strength to ward off its only predator. Wrenchbills rarely back down from a fight: if a herd spots a sirenfowl, its dozen or more members will give chase all the way to the edge of their territory, hopefully ensuring the hunter never gets the chance to set up camp around a body of water therein.

One more step towards the most derived Unciolan seacocks is largest animal on Unciolis: the Trumpeter Seacock (Buccinasapteryx pentacuspis). This three-meter-high, nearly half-ton beast travels alone across the vast forests far from the coastlines. It feeds high in the trees, unhindered by the Scansoriarthriform isopods that would pester it in analogous habitats on the mainland. As it has access to all the tender young shoots of the hybrid-trees, it has no need to consume woody matter, and thus its beak has adapted purely to stripping leaves off branches. Its lower jaw has a series of tooth-like points that serve to scrape away vegetation, acting similarly to the tongue of its Panapterran counterpart the raspbird. Adults are essentially invulnerable to sirenfowl attacks, but mortality rates are high in their chicks. To cope with this strain, trumpeters are highly diligent parents, never leaving their young's side until it reaches about six months of age, at which point it is large enough to fend for itself. Now with no need for one another, the mother and father also go their separate ways, but they always manage to find each other again the next time mating season rolls around. This is because of their incredibly loud and individually unique call, produced in a resonating chamber created by the soft tissue of what used to be a normal seacock salt gland. As trumpeters live nowhere near saltwater, this excretory organ was repurposed into a communicative one, allowing pairs to locate each other after many months or even years apart. 

The final three species belong to the same genus - Humulapteryx, from which the tribe gets its name - but have all diverged from each other physically and behaviorally enough to merit their own discussion. They are the Springerbirds, united by their elongated tarsometatarsus, making their foot as long or longer than the rest of their leg. A lesser degree of this condition can be seen in their trumpeter cousins, but only the springers utilize this piece of anatomy for the behavior that inspires their common name. All Humulapteryx are impressive jumpers, able to leap many times their body length from a standstill. They can also hop as a form of locomotion, which while slower than running is more energy-efficient due to an elastic tendon in their heel that stores and releases energy with every bound. 

The smallest of the three is the Snowspringer (H. fraterculoides), whose range roughly overlaps with that of the largest bird on the continent. Spending the frigid winters inland, it has developed a dense coat of feathers to keep it warm. Also like the trumpeter seacock, it has found a new use for its salt gland. During wintertime, the otherwise functionless lump of nasal flesh grows fourfold, creating a winding passage to warm up the air the bird inhales. This greatly reduces heat loss in the core of the bird's body, while the extremities are allowed to drop closer to ambient temperatures. As late winter is the time of year when snowspringers find their partners for the upcoming mating season, the noses of males also become colorful during this period, gaining stripes of black, orange, white, and yellow. On occasion, an especially frigid day will force this courtship to an early end as snowspringers seek out whatever shelter they can find. In such dire circumstances, one final trick allows them to take advantage of the best source of warmth imaginable. Snowspringers possess a crest of white, downy head feathers that make them appear, from above, nearly identical to trumpeter seacock chicks. This means that if they can locate a trumpeter - an easy task, given how clearly they advertise themselves - they can huddle up and ride out the storm. This trick is eventually noticed by the larger bird, but since the snowspringer poses no threat to the trumpeter, the latter usually lets its smaller companion stick around anyway.

Next is the Streamspringer (H. ripariensis), which occupies the niche once held by the sirenfowl's ancestors when they were alone on the continent. Wading along riverbanks and other areas of shallow water, it strikes quickly and decisively at swimming creatures, using its long, sharp beak to skewer its prey. This puts it in prime sirenfowl hunting grounds, so it must remain ever-vigilant if it is to survive. Unlike other springers, it travels in large herds, with members taking turns scanning for threats. At just over twenty kilograms, it's much too small to put up a fight, so it flees at the first hint of danger. Even though running would be faster on dry land, when fleeing from ankle-deep water it usually hops, as this allows it to spend much of its stride length above the water's surface, reducing drag and ultimately offsetting the loss of speed. Despite this, the two's constant proximity to one another means that the streamspringer makes up over a third of the sirenfowl's caloric intake. 

The Sandspringer (H. littoralis) is the sister species to the previous one and resembles a larger, more powerfully-built streamspringer. It lives in both tideslopes and matkelp coasts, relying on wide, webbed feet to keep itself from sinking into sand or algae. It is a fisher like its closest relative, but it also dives in the water in pursuit of prey. Its niche is essentially that of a giant mudtrotter, except that it is a strong enough swimmer to compete with the dedicated pelagic seawis, so it sometimes ventures a great distance offshore. This generally keeps it out of contact with sirenfowl, but it means that it must contend with the giant predators of the sea, from massive stoutlings to thalassaurs to the sirenfowl's own closest living relatives the oarbirds. When it returns from its fishing trips, the sandspringer is large and fast enough to infrequently hunt apterrunners and the chicks of larger birds if they're left unattended. When it comes time for it itself to breed, it journeys to the highlands hundreds of kilometers from its normal coastal home so its young can be brought up on the easier prey of freshwater fish. Even during these forays, sirenfowl have difficulty catching them, as their lifestyle makes them just as home in the water as the hunters, being the only species that can sometimes win the breath-holding contest, after which the sirenfowl is forced to release it.

Vagrants and Visitors

Though only three air-breathing vertebrates have ever made Unciolis their permanent home, a wider variety of creatures pass the continent by or rely on it for only a part of their life cycles. As has been the case for many millions of years, stoutlings are among this group. Though the Ice Age destroyed the giant lakes of the past, smaller refuges still exist, such as the two in the southwest that serve as the breeding grounds of the two species of Bullhead Stoutling (Pravicauda fortis and longidens). Though these reach lengths of 250 and 220 centimeters respectively, they belong to the semelparous branch of their family, being the first and second largest of their clade. Unlike the rest of their subfamily, males are the smaller sex and make the journey along with the females, living a month or two longer than their mates to protect their vulnerable young from the multiple species of fishing bird that dwell in the region. Unciolis is also the home of the smallest red stoutlings, known as Flatbelly Redstouts (Planiventrichthys unciolensis). Their body shape is an adaptation that helps them make their way up shallow, oxygen-poor streams that lead to the mountain lakes where they give birth. A subspecies called the Lake Flatbelly (P. u. lacustris) became isolated in one such lake about 100,000 years ago and is now fully adapted for freshwater life, having shrunk by about a third and adopted a more upward-facing mouth to catch small prey from below. 

Oarbirds also come to Unciolis to breed, especially the Least Oarbird (Orcinapteryx minimus), a 125-centimeter species that spends the rest of its time in the tropics of the Interthalassic. Like all kiwis besides steppesteppers, it only lays one large egg in a clutch. This has been a perennial issue for oarbirds, which cannot meaningfully defend their one precious chick, and its relatives have all responded by reproducing on predator-free islands. The least oarbird has a different solution. Nearly every egg contains a double yolk, yielding two chicks instead of one. Hatching at around half a kilo, the siblings must work together to crack the eggshell; if one grows too weak, the other won't be able to gain enough leverage to break its way out, so both will perish. But most of the time they succeed, emerging into the world together and helping one another survive their first year as terrestrial generalists. For a time, they may even integrate into a flock of apterrunners. After growing more than a dozenfold, they find themselves growing clumsier on land and increasingly drawn to the sea. Still they travel as a pair, seeking a pod of same-aged peers to reach maturity with. They may only willingly separate when one or both find a suitable mate, though just as often the two couples may remain together as a miniature pod for life. 

Unciolis's first-ever reptilian fauna arrived about three million years ago as thalassaurs expanded their range throughout the Interthalassic ocean. The Southern Diamondtail (Dimorphogekko australis) is the result of this radiation, and females can be commonly seen basking on the sand while their mates patrol the water nearby. This species has lost all remnants of external claws and digits, having fully specialized for life at sea. Laying dozens of eggs at a time, it has not needed to resort to strange reproductive habits like the oarbirds have. Instead, it simply abandons its clutch and returns to the open water, far from shore, where it is the apex predator. While females are not much bigger than their ancestors four million years ago, males of five meters or more are not uncommon.