Invertebrates of the Cryocene

Insects, arachnids, crustaceans, molluscs, and cnidarians have called Serina home since even before the introduction of the canaries. More than 50 million years on, a relatively small group of founders have given rise to many new and novel lineages.

Ants

The leafcutter ants and their descendants, the Phytosocianae ants ("plant partners") which live in in mutualistic partnerships with most Serinan bamboo groups are not the only ants of the Cryocene. The Formicidae are still among the most successful insect groups on the planet and occur on every landmass. The original process of evolution which gave rise to the mostly flightless, subterranean ant as we know it in the Cretaceous era has worked backwards on some of them, giving rise first to the primitive gnat-like honey ants, which were mainly nectivorous, which have now split into three distinct groups - the true honey ants (which are still nectar-drinking and often social, very much like honeybees), the more generalized hymflies, which are usually solitary and take diets ranging from nectar to smaller insects to carrion and even blood, and later to several other wasp-like lineages which keep their wings throughout life, exhibiting a wider variety of lifestyles including sharp-jawed, agile predators that feed on other insects. Known as vespers, they are a polyphyletic assemblage of at least three independently derived groups, some descended from honey ants and others independently derived from basal ant ancestors but all of which for the most part are similar enough in relation to one another than their exact ancestry is not of importance to the layman. Some vespers produce venomous stings like wasps, defensive and offensive abilities which have already evolved and been lost several times, while one solitary group known as the fangflies has evolved large, mobile jaws and a venomous bite to subdue its prey. Vespers may be either social or solitary, hunting alone or building nests in trees or underground. The largest solitary species, adept pursuit predators in the air with two pairs of independently mobile, dragonfly-like wings, reach five inches in length and may occasionally take small birds as prey, while smaller but highly aggressive swarming species are capable of killing much larger animals to defend their colonies.

In the inverse, small blind ants which spend almost their entire leaves deep below ground have evolved, converging on termites. Some forms even built towering mud structures for their colonies on Serina's plains, and at the shores of the equatorial oceans, specialized mangrove ants survive in a world that is submerged in seawater almost 50% of the time.

Crickets

The burrowing crickets of the Hypostecene and early Tempuscenic have continued to diversify and spread across Serina, becoming both herbivores - like voles - and carnivores - like moles. Herbivorous species tunnel just beneath the surface of the soil, chewing at plant roots and tubers, while carnivores burrow down deeper in search of worms and other meaty prey that they dismember with large, sharp mandibles. Though most species are small, in the range of one to two inches, relative giants still exist. Burrowing crickets often live longer lives than their ancestors and survive multiple seasons, surviving winters by burrowing deep underground below the frost line and hibernating. Some species from temperate seasonal environments, having very slowed metabolic rates and needs for food, may live twenty-five years and attain a weight of four pounds. Herbivores feeding on the sap of tree roots, they avoid most predators by merit of almost never coming above ground. Their anatomy has changed markedly to facilitate this lifestyle, their hind legs becoming small and their front legs adapting into enormous claws to move soil. They are blind and basically deaf, relying entirely on their sense of smell and touch with long sensitive hairs on their bodies and lengthy antennae. They have lost their wings entirely.

Other crickets have evolved down an opposite path, becoming better flyers. Large herbivores, some exhibiting bio-mimicry to resemble leaves or twigs, others known as florgusts with giant brightly-patterned wings, flutter through forests and chomp on leaves. Species have diverged which take alternate food sources, including fruit and nectar. On the plains powerful jumpers reminiscent of grasshoppers have evolved. They typically have well-developed wings as well and some are migratory, following rains to ever-greener pastures. Though their numbers are normally small, like locusts they may periodically explode into plagues when conditions are right with potentially catastrophic consequences to grazing animals, but producing a flush of food to insectivorous birds.

Crickets have also adapted to more generalized cockroach-like niches, omnivores that scurry through the leaf litter of forests and eat decomposing organic matter. From this group has also arisen a lineage of raptorial predators that catch other insects in sharply-clawed forelegs.

Some crickets combine behaviors of several of the above groups - spending many years underground as blind, wingless nymphs feeding on roots, they may molt periodically into winged and sighted adults, all at once, and take flight as a swarm to feed and breed for only a few weeks every ten or twenty years.

Beetles

Ladybird beetles have diversified, including the cuckoo ladybirds whose larvae have become almost indistinguishable from those of the ants they predate, but the ants are not always such unwitting surrogates anymore. Whenever a beetle becomes too aggressive in parasitizing an ant the ants realize something is wrong and tend to become wise to the trick and finds the imposters, killing them but unintentionally selecting for baby beetles that are even more similar to their own babies. Eventually, the larval beetle is so indistinguishable from its own infants that the workers can't find it. The parasites proliferate, eating up their hosts rightful young, until the colony may eventually collapse. Fortunately for the cuckoo ladybird, there is still an almost limitless number of other naive species to pass its young off on with only a slight change of perfume needed to mimic the new "adopters' scent and trick them into adopting the killer baby. The larvae now don't look exactly like those of this species, for they were adapted to mimic another which has either died out or become too uncommon for the beetle to bother with. The cycle thus repeats, with the beetle larvae coming to look more and more like its hosts until either the ants end up caring for nothing but a nursery of killers, which eventually molt in beetles and leave the colony vacant of labor and doomed to die, or oppositely the ant becomes completely wise to the beetle's game and able to detect the slightest difference in the parasitic larva, becoming intolerant of any of them. Unfortunately, the latter scenario can also go another way; in a desperate attempt to save their colony, worker ants can become confused, killing and mutilating every single larva indiscriminately, including their own, and doing themselves in in an ironic twist of fate.

Burying beetles have produced a wider variety of descendants that fill different niches. Some eat the dung of birds, others have become more mobile flyers that lay their eggs in carrion without burying it, like flies. Fast-running sorts have become active predators on the forest floor.

There are few herbivorous beetles on Serina, with crickets and ants filling most of these niches, though the larva of some burying beetles have adapted to feed on plant matter underground.

Mites

The small biting mites introduced to Serina very quickly swell to larger sizes, some becoming tick-like. Active predators appear from the detritivores, giving honor to their relatives on Earth, the spiders, as true hunters. Proper web-building has not evolved, but varieties exist which shoot their victims with silken threads to snare them and then reel them in to kill with a venomous bite.

Crustaceans

Copepods are now major players in Serina's sea as they are on Earth, forming a significant percentage of zooplankton. A myriad of almost microscopic species occur in such numbers as to be all but impossible to estimate near the water's surface, feeding on microscopic algae and forming the basis to the marine food chain. They have also produced larger forms, however, several inches in length, which shoal like krill in enormous numbers, feeding on the zooplankton and themselves being fed upon by fish, seabirds, and of course the majestic birdwhales.

Shrimps descended so long ago from the diminutive, freshwater Neocaridina are also diverse, ranging from free-swimming krill-like varieties to large predatory prawns, one group of which is experimenting with gliding out of water to escape its own predators, using wing-like paddles derived from one pair of its legs. They're omnipresent at sea and in inland waters along with the generally more armored and less mobile crayfishes, which are beginning to give rise to short-tailed crab-like representatives as well as giant oceanic lobsters and primitive burrowers.

Hermit crabs are universally abundant in the shallow sees and warm beaches near the equator. Only aquatic forms were introduced, but some quickly re-developed a fondness for land. Some have gone so far as to leave the beach and move into the subtropical forests, going to water only to breed, and then in freshwater pools rather than the sea. They begin to forgo a larval stage, hatching into miniature versions of the adults which are aquatic for their first few months until they too leave the water. To survive the cold in more seasonal climes, some burrow.

Triops are effectively unchanged, common across Serina's driest environments, doing the same thing they've done so well for now over 350 million years.

Molluscs and Cnidarians

Snails are still numerous, but on land they will never again reach the sizes they did in Serina's first few thousand years - predators now abound. In the water they are preyed upon by large prawns with powerful claws which find the weak points in their shells, smashing them open; on land specialized ants do the task, chewing away the "hinges" of the door-like structure the snail closes to seal itself inside and carrying the shells underground to use to shelter their eggs and larvae - but the snails are not totally without defense. Some small arboreal species, when pressed by their ant predators, can vault themselves off a branch with an explosive pop of their "door", falling to safety somewhere lower in the canopy. When the danger is gone, they emerge and crawl back up a different tree.

Grazing sea slugs still grow to larger sizes than they ever have on Earth in Serina's warm waters, some as big as manatees, where they feed on algae and other water plants. Some of the most unusual survive in a world of keen-eyed hunters, despite being almost blind, by being extraordinarily poisonous. Their danger makes them beautiful, however, brightly colored and tasseled with strange display structures, floating silently through the shallows like aliens from another world. Some forms known as mollontees have developed sharp stinging tendrils that coat their backs - an armor impermeable to any predator, but to which a handful of specialized fish have forged an alliance with. Protected by thick mucous on their bodies, squat little platy descendants called daredevils make the backs of the slugs their home, much like a more mobile version of the clownfish/anemone symbiosis on Earth. As the slug swims around and searches for food it disturbs a constant stream of small zooplankton as it pulls up the plants from the sand - a feast the daredevils quickly zip out to catch before darting back to the safety of their deadly abode.

above: a deadly poisonous mollontee swims idly through the shallow tropical seas, a family group of daredevil fishes nesting in its stinging back tendrils for shelter.
Art by Trollmans.Deviantart.com

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Bivalves have become Serina's first reef-builders, the calcified shells and the resinous glue they use to attach themselves to the sediment with forming lasting underwater mountains of limestone. Forming only where currents bring nutrients to near-shore environments, they are less common than coral-based reefs which can survive anywhere the sun shines brightly enough, but where they do occur they produce an exceptionally rich community of plants and animals. Living clams attach in great numbers at the top of the reef and from there they filter feed, adhering to the shells of many generations of their deceased elders, while plants and algae also gain a foothold, even on the shells of the living bivalves themselves, while generation's of hollowed-out shells provide a deep, labyrinth-like shelter in the heart of the reef for a wide variety of aquatic animals to make their homes. Oceanic hydra have developed forms likely similar to the ancestors of coral and anemonies; much larger than their early ancestor, they attach to the tops of the reef with their own calcified crampons and compete with the clams for zooplanton as it floats by, with some of the larger species feeding on fish. Many varieties blossom like flowers at the tops of the reef, their tissue colored brightly with photosynthetic algae, as they slowly reduce their ability to actively feed and rely predominately on energy taken from their new symbiotic partners. In the coming eons, these cnidarians are likely to displace the bivalves as Serina's main reef builders and converge further upon their distant Earth relatives, the corals.

Hydra have also evolved more mobile descendants. Radially symmetrical, flattened hydras develop a convergent appearance and behavior to the starfish, crawling over the sea floor, their mouths turned down to the sand, as they hunt actively for small animal prey - the difference being once they find it they ensnare it in a mesh of venomous tentacles. Jellyfish, the hydra's distant relatives, have so far undergone few major innovations, their ancestral habits being as suitable today as tens of millions of years ago.

above: a variety of hydrambularans - a clade of large starfish-like hydras - native to Serinan seas 50 million years PE.

The driftwood stinger is among the most primitive walking hydras; it can move freely only early in its life. The stinger feeds on small fish and plankton caught in its stinging tentacles and is sessile as an adult. Young stingers attach their foot firmly to a piece of floating wood and cement themselves permanently with a glue-like secretion, spending the rest of their lives in place and budding off smaller clones until a small colony is established. If food is abundant, the clones remain around the parent and a large group develops, but if food is scarce they will detach and float away to find a new log to colonize.

The deadman's hand is a primitive walking hydra that retains a body and a foot it uses to inch itself along the sea floor in search of small worms and fish buried in the sand, which it stings with its tentacles. Its venom is weak, only enough to stun small prey, and of little harm to larger predators, so this species spends much of its time hiding in the sand.

The bloody mary is the most derived species pictured, having reduced its body into a flat round form that most closely resembles a starfish. This species is also a bottom-dwelling predator of sand-dwelling prey, but it is marked boldly with spots and stripes of red and white, advertising rather than hiding itself. This is because the bloody mary is particularly venomous and will quickly turn around and sting any creature that attempts to bite it severely enough to cause death through cardiac arrest.