Armouring for the cold

Armadrails have greatly declined in Antarctica since the Cambiocene, with only a single lineage managing to survive around 10 million years ago. The reason for this decline lies in their unique yet unfortunate adaptation of having a relatively low metabolism to reduce energy consumption—an adaptation that would be extremely useful in many environments except for the frigid one now found in Antarctica. Nonetheless, this single surviving lineage has managed to persist until now, making an unusual comeback after the Continental Crisis. The species of interest is the omegascute (Scutisilva fortipes), an omnivorous creature that mostly dwells in the Follia Plateau, where fruits, seeds, insects, and carrion are more abundant.

The omegascute survived the Crisis thanks to several adaptations suited for living in colder places. Unlike its ancestors, it completely lacks exposed dermal scutes, which are now hidden under a dense, dark plumage that helps collect heat by reducing the albedo effect.
Its generalist and opportunist diet, which is often composed of carrion (ranging from 40% to 90% depending on the season), provided a significant advantage. Additionally, the Continental Crisis brought another generalist animal, the erosion-pole, to the brink of extinction. With fewer competitors, the omegascute quickly recovered to a decent population size, effectively ousting the previous dominance of erosion-poles.
Despite these advantages, living in the Sanctuary Plateau is far from easy, and omegascutes must defend themselves against the continent's fierce predators. When harassed by similarly sized predators, the omegascute typically forms an impenetrable barrier by curling into a ball-like position, similar to an armadillo, exposing only its neck, which is plated with larger scutes compared to the rest of its body. The upper part of the head is also keratinized for defensive purposes and creates a continuum with the beak.  When facing larger predators, the omegascute usually runs away, seeking shelter in large herbivore herds, and only rarely tries to defend itself with its long, keratinous caudal spur, which can inflict brutal injuries on an enemy.

Like its ancestors, omegascutes must hibernate during winter. However, the soil of the Follia Plateau is far from optimal for digging burrows due to permafrost, so a significant portion of the omegascute population migrates towards the Seamount. This hilly environment, rich in caves and areas with softer soil, provides a suitable habitat for wintering. It has been observed that individuals hibernating in this region have more than a 70% chance of surviving the winter. However, if the cold continues to advance as it has in the past, the hilly and shrubby environments of the Seamount will be completely annihilated by the cold in a few million years.

Despite their currently stable population, omegascutes and the other Antarctic biota must prepare to face something far worse than an annoying competitor. The relentless advance of the ice threatens their very existence, reminding us that the stability of life in this harsh environment is always precarious, and survival often depends on the ability to adapt to the ever-changing and unforgiving conditions.