Seawis and Monitor Geckos: Life on the Shoreline

Over the past 900,000 years, the Gecko Isles have become a very different place from the Early Muricene patchwork of semi-arid peaks and woodlouse-grassland valleys. Changing ocean currents have increased rainfall across the area, promoting the growth of large groves of pseudotrees where grasslands once dominated. Droughts are now extremely rare, and truly open land is only present around a few patches of seasonal psuedoforest. Strong winds, driven by the flow of water around the Isles, break apart any large algal mats, resulting in pristine beaches across the Isles. The waters here are extremely fertile, as dead organic matter flowing out of the Loxodian-Abelian inland seaway is dumped into the ocean surrounding the Isles. Blooms of green algae feed massive mosquitofish and copepod populations, while certain salt-loving water-lily-like baskets grow in the sand. Reed-like forms are scattered across the foreshore, and small amber skystalks cover the dunes. In this tropical paradise, a diverse community has sprung up to take advantage of abundant local resources.

Vampire lizards (Haematogekko) are a common sight on every Isle, though each has its own endemic species because they tend to be only mediocre swimmers. Some specialize on picking off beached fish at low tide, while others are more adept at draining the blood of their reptilian relatives. They can reach impressive sizes, nearing half a meter in some piscivorous forms. The reigning monarchs of the beach, however, are the monitor geckos (Varanogekko), a collection of large-bodied squamates that occupy an apex predator niche across the Isles. While inland species are generally of moderate size - an adaptation to help navigate tangles of vegetation in dense pseudoforests - the beach-dwelling members of this genus have no such constraints. As such, they often reach more than a meter long, patrolling the shores and crossing freely between the various isles. Very rarely, they even approach mainland Abeli, though rats prevent them from establishing breeding populations there. 

The genus Thalassaurus spends the majority of its time in the water, swimming through vast beds of semi-aquatic basket-grasses at high tide. An omnivore, it is equally happy to snack on plants, fish, and even smaller members of its own genus. Given their prodigious swimming abilities, the thalassaurs are certainly capable of reaching the Abelian or Loxodian coasts. However, since their food source is tied to the intertidal meadows endemic to this region, they tend to keep close to the islands. In fact, no gecko has so far successfully established a population outside the Isles. On their shores, though, lives one animal group that makes this crossing routinely.

The seawis (Pelagapteryx) are composed of around a half-dozen species, all descended from semi-aquatic ancestors in the Early Muricene. Their seafaring abilities have been greatly refined over the millennia; all seawis now possess a salt gland that allows them to remain at sea for long periods of time. They additionally have dense, downy feathers, trapping a layer of air that improves buoyancy somewhat. Seawis often dive beneath the waves in pursuit of fish, which are their primary food source. To aid in this, they have straight, sharp bills that are very effective in skewering their prey.

The most abundant Pelagapteryx species across the isles is the Common Seacock (P. regalis), which is also the smallest seawi in existence. No larger than an Earth quail, they find safety in numbers on the Gecko Isles. Millions breed here year-round, especially on the smaller islets where no predators can reach them. As they rely on the isles for their reproduction, their range extends only to the nearby margins of Abeli and, rarely, Loxodia. The transcontinental seawi (P. piscivenator), however, is large enough to hold its own on mainland coasts, standing more than a meter tall and armed with wicked claws for slashing any potential egg thieves. As such, it is found across all of Panapterra and beyond. Secondarily terrestrial offshoots of this species can be found further inland on numerous islands outside the Isles; over two dozen subspecies have independently taken advantage of the fact that similar islands elsewhere in the world have no other large carnivores. Besides such insular apex predators, though, the global population of this species is very homogeneous, with high rates of gene flow across thousands of kilometers.