The Life of the Undersea Savannah

Life of the Undersea Savannah

above: the undersea savannah

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The undersea savannahs of Serina's shallow seas in the Pangeacene - immense tracts of underwater grassland founded by sea bamboo, are a hotspot for marine life. Exceptionally rich in nutrients, they support an incredible bounty of animal life, from the smallest planktant to the largest grazer. Shoals of colorful fish find food in the grass, sheltering under the bodies of large grazers for protection from their own predators. Herds of herbivorous burdles, gentle and easy-going, glide over the submerged plains like their ancestors once did in the air. Primitive sea birds mimicking gulls and ducks flock along the surface, feeding on abundant fish, invertebrates and plant foods and nesting on nearby land, laying hard-shelled eggs and raising chicks as they have done for millions of years. Even after 228 million years, in fact, these conservative, familiar forms persist, providing a stark contrast to the strange state which evolution has bestowed upon their distant kin from whom they split millions of generations ago. The ancestors of both burdles and Serinan sea gulls reached Serina as canaries. Technically, no matter how divergent they become in form and habit, both still are. Though fertile reproduction between their lines ceased almost at the start of Serina, they remain tied together - however bizzare the concept would seem - as kin, isolated here on this strange world more than two hundred million years ago.

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One of the most unusual grazers of these aquatic grasslands is the eight-foot long manatweet, an herbivorous descendant of the water snuffle with a highly flexible upper lip which it uses to pull vegetation into its mouth. A diet of plant matter, rather than molluscs, has caused the sensitive feelers on the snout to shrink while the entire appendage became a small grasping trunk ideal for such a purpose. While some its kin - the mitten and the glove - returned to land, the manatweets have gone further down the path of aquatic adaptation and are now almost completely independent of the shore. Spending their lives floating leisurely in these warm shallows, propelled with powerful beats of large webbe feet, they must still come ashore to rocky offshore islets and protected coves to incubate their single large egg. To do so, they push themselves out of the water with the large hind feet and rise to rest on a cushion of fat on their rumps, incubating the egg on top of their feet and adjacent to a featherless patch of skin on their stomachs, much like some penguins once did on Earth. The chick which hatches is precocial and can swim and feed itself almost immediately, but remains with its parents for several months to protect it from predators.

Manatweets are on the way to losing their feathers, as do all totally marine birds, since birds cannot rely on them for insulation if they cannot leave the water for a time each year to molt them. They retain a short, shaggy pelage over their bodies and have been slow to lose it, as their leisurely lifestyle means the resulting drag is not a major problem for moving through the water, but it no longer serves any purpose, being too sparse an unkempt for insulation - instead, the body is insulated by fat. Chicks are initially insulated by down but only for the first few weeks of their lives, after which they have laid down enough fat to do the job. Manatweets are omnivorous in infancy and hark back to their ancestors, catching any small fishes or invertebrates they come across rooting in the grass and using this extra protein to fuel their rapid growth. Adults, however, are almost completely herbivorous, only consuming animal food accidentally while grazing.

Another large marine bird shares this habitat with the manatweet, but its behavior and form are very different. This creature, though comparable in size, has four flippers, not two. Its feathers are even more reduced, limited to bristle-like whiskers on its snout and a short layer of vestigial fuzzy filaments, and its snout is long and its jaws full of needle-like teeth well-suited to catching slippery prey. It swims at a much more hasty pace with alternating pulses of its fore and hind flippers, chasing small fishes. It is a dolfinch, a fully-aquatic bumblet descended from the estuarine bumblet. It has grown further in size dramatically, becoming megafaunal.

Dolfinches catch their food in toothy jaws, uniquely among birds of the Pangeacene since the extinction of all other vivas; like their kin, however, they still sport specialized keratinous teeth on their tongues and beaks. Some of their distant herbivorous relatives of bygone eras developed especially sophisticated chewing mechanisms with their tongues and bill teeth, but the ancestors of the dolfinch diverged and went down a carnivorous path very early on, before any of these adaptations had appeared. Instead, they use their teeth only to grasp prey and have developed teeth in the lower jaw as well as the upper to assure a firm grip. The tongue is not used in biting or chewing, but in some dolfinches the teeth present upon it have specialized instead into elongated baleen-like filaments used in filter feeding just like the pelecanaries of eons past. By pushing the tongue against the upper jaw, these filaments serve to seine microrganisms from mouthfuls of water.

As aquatic as the dolfinch has become, however, it is still beat by another group which calls the undersea savannah home. Totally aquatic changelings, descended from species with aquatic larvae, have now settled in the sea. They are highly neotenic creatures, maturing in an effectively larval state and never developing into a flying or feathered adult form, but also extremely specialized in their own right. They have transformed the tadpole-like tails of their ancestors into fluked fins with a jointed, bony internal support, and they have re-developed gills from what was once the ear canal of their flying ancestors, a necessity once they reached a size larger than allowed them to breathe with their skin alone. Reproduction consists of nothing more than the release of eggs and sperm freely into the water. The result is an extremely impressive impersonation of a fish, though a few traits easily distinguish them from most of Serina's true fish stock; their fins are fleshy, without rays, and inside their flippers can still be found the remnant bones of a jointed wing. They have a neck, albeit a short one, which can be rotated to feed and look around. And they still retain a beak, the shape and form of which varies depending on their diet. They have taken the most extreme return to the sea of any land creature, and now fly through the sea in flocks as their ancestors once did the air. Most forms remain social, and with acute eyesight, they compensate for the loss of their hearing with exquisitely vibrant markings, making them among the most brilliant of all "fish" to be found on the savannah.