Omniphages | (The Megafaunal Molodont)

On a muddy shoreline on a hot and humid midday in the wetlands of Striata, 220 million years P.E., a group of cantankerous creatures is resting. The past night, they would have wandered widely around the nearby forest and tall grass meadows, eating just about anything that they could fit into their huge mouths, lined with robust chewing teeth that identify them clearly as molodonts. But now the sun is high and hot, and now the horned gnashers are growing irritable and lethargic. Around two hundred and fifty pounds each, they are enormous molodonts, some of the biggest of this newly-diversifying clade of tribbetheres yet to live. They have grown to such a hefty size to maximize the efficiency of their digestive system, which can make use of foods few other animals can. Gnashers belong to a new branch of molodonts called omniphages, which have evolved an extremely generalist diet, using their specialized jaws to obliterate plants and animals alike, living or dead, and to break apart foods too hard for most creatures to bother with including bones and the wood of trees. Though their preferred foods are soft grasses and root vegetables, the key to their success is the ability to consume nearly anything and get some energy out of it. It is an excellent representation of how specialized traits can be exapted for uses they were not originally adapted for: once a small seed-eater, the horned gnasher is now a living garbage disposal. 

Gnashers have evolved the strongest bite force of any Serinan animal to date, able to crunch down with some 12,000 pounds per square inch. Its tooth plates are gigantic and broad, letting it engulf its food and crush it to dust. Its large size improves its digestive capacity, letting it hold such barely edible materials as wood in its gut for days at a time to ferment; symbiotic stomach bacteria break down the cellulose in plant foods so that this molodont can make use of the energy they contain, a trait that gives it a competitive edge of other herbivores of the era at eating woody plants. Such a wide range of suitable foods means that many gnashers can be supported in a habitat that couldn't maintain large numbers of more picky eaters; populations of this species can rise to explosive levels, which are then eventually culled back down as predators increase in number to match them. Almost always found in large herds of thousands, during peak abundance they can strip their preferred wetland environments bare and contribute to erosion of the land as the soil falls away without roots to support it; this in turn makes larger lakes and increases the extent of wetlands by flooding nearby plains and forests, making the gnasher an ecosystem engineer. When preferred foods are scarce, horned gnashers speed along the process of turning forest to wetland by eating the trees, one chiseling bite at a time, starting with the nutritious bark. They fell the trees as they feed - occasionally getting killed beneath them if they don't pay attention to the direction they fall. Felled trees are stripped around their edges of bark, like corn on the cob; the dead inner heart wood is only eaten if there is nothing better to fill up on, and takes significantly longer to break apart. Still, when numbers are high, a herd can fell and consume an entire 70 foot high tree in a matter of only three or four days, leaving nothing behind. Never before has Serina known such a destructive species, and the gnasher will contribute to a decrease in forest coverage in coming millennia.

Though the horned gnasher, like all true molodonts, has only two "teeth" used for chewing, males of this species have uniquely developed additional teeth outside the mouth, on the lips, which are used as offensive battering rams when fighting one another for mating rights. These supernumerary teeth are structurally homologous with the ancestral teeth of earlier molodont ancestors, otherwise now fused into the solid upper and lower plates of the molodont jaw. They are absent in most females, though rarely appear in much smaller number. Like the rest of their teeth, they grow continuously from the root and so regenerate when worn down through rutting. Males can use their teeth not just to fight rivals but also to gore enemies; it might seem that such a weapon would also benefit females, but there is likely a reason they lack these extra teeth - the tusks would get in the way of feeding their offspring. Among molodonts, the horned gnasher is a doting mother, and just one or two young is born at a time, which are born with only the initial sprouts of their primary teeth, and so depend on their parent to regurgitate food for them for several months before they can be weaned. The young are too small to ferment their food as can the adult, which would mean they could not survive on such sparse diets as wood on their own. But because the mother can provide for them, regurgitating a digestive slurry from the depths of her own gut which has already had all the energy extracted by her own gut bacteria, her young can remarkably grow up and be raised even if the mother's diet is limited to the most fibrous, nutrient-poor foods conceivable.

It's an adaptability to hardship that birds could only dream of, as the molodonts rise to prominence as megafauna for the first time as the Pangeacene goes on, bringing lasting changes to the world in their wake.