Soggobbler and Sirenhorn

The divisions between the soglands and the upland plains were already muddy in the start of the hothouse, as animals from either habitat could easily wander into the other. Yet there were decidedly distinct differences in these habitats, one being a drier traditional grassland, the other a perennially flooded delta. Early crested thorngrazers split along two lines of evolution, with battering helmetheads favoring the higher ground and rumbling ones preferring the wetlands. But now a new rival has appeared on the soglands - a huge, aggressive animal that wants to claim habitat all for itself, and has the power to do so. To avoid it, the lowland thorngrazers have had to do two things; become faster and more agile, and spend more time on the uplands, even if it has meant butting heads more often with their relatives who went there first, because anything is better than coming face to face with the soggobbler - an animal so large and powerful in comparison to the thorngrazers which evolved without anything tougher than themselves around that, to their eyes, it might as well be an eldritch monster.

A huge herbivore like none to walk this world before, the insatiable soggobbler is now the biggest animal on Serina's soglands, which thanks to its presence is now a very different place than just five million years before. 

Skuorcs continue to find great success as the hothouse marches on, their quadruped stance and long tails allowing this group to adopt bauplans impossible for other animals. Four legs allow for stable support of increasingly large body sizes in the herbivorous descendants of scrunges, as well as allowing easier digestion of vegetation in a massive fermenting stomach. Meanwhile, their highly mobile, scute-armored tails provide balance and, whipped at their enemies, are now an additional form of defense. A new clade of giant quadruped birds has arisen - the gantuans, long-necked herbivorous skuorcs that are now some of the biggest land animals alive, though another closely related skuorc group has already reached an even greater weight.

With long snouts (and even longer necks), wide shoveling bills, and sharp beak pecten which let it cut grass in huge mouthfuls, 30 foot long, 2.5 ton soggobblers are a species of gantuan still common to the lowlands, where the ancestors of the whole group arose five million years ago. Mostly without feathers, plumage still covers their backs and near the head of these creatures, with males showing some brighter colors in the short fuzz that grows over their faces. These animals now compete effectively against the chewing thorngrazers simply by growing so much bigger, allowing them to displace the less armored species from their feeding grounds with highly aggressive temperaments to secure the best forage to the exclusion of their competitors, who no longer rule this landscape as they once did. This has forced the herds of smaller crested thorngrazers to spend more time in the uplands, which the soggobbler, adapted to eat soft wetland vegetation, mostly avoids. Though their feeding is not as efficient as the thorngrazers', for they are unable to chew what they bite, the sogland grasses are watery and not difficult to crop - further, bigger gantuans can eat more of it faster, relying on muscular gizzards and gastroliths to digest plants instead of chewing teeth. Herds may migrate tens of miles to access loose stones for the purpose, along larger rivers or the higher volcanic hills.

Such a great body size has evolved very quickly in this species, putting not only other herbivores but contemporary predators in an arms race to keep up -  and to discourage enemies further, soggobblers are highly social and gather in immense numbers which keep a collective eye for danger. Combined with their ornery nature and predilection to strike opponents across the eyes with their tails, few animals have evolved which can reliably hunt adults. Their numbers now grow with few limits, to the point that they are the most numerous megafaunal animal of the soglands, requiring thorngrazers that still live there full-time to become smaller and faster to compete.

It isn't only active aggression that is now pushing other species from this previously highly bio-diverse ecosystem. The soggobbler's life history compared to its rivals also changes the ecology of the region. The earlier community of thorngrazers, trunkos, and other varied species each filled a single niche, with young being attended by the adults and filling the same roles in the environment. Gantuan chicks on the contrary are born independent, and don't fill the same niche as the adults. They begin life as highly insectivorous little creatures not much larger than chickens, and hunt the swamps for insects and other small animals. As they grow they become mid-sized selective grazers of the most nutritious newly grown plants, fruits and seeds. Adults are slow, gregarious non-selective grazers that feed in big, undiscerning mouthfuls. This means that a population of varied-age soggobblers, particularly one with few constraints, fills all of the niches formerly adopted by a dozen or more megafauna species, and quite literally leaves them without room. Juvenile survival is higher than would be expected because young frequently follow adults, feeding on insects disturbed by their grazing, and so receive incidental protection from proximity to the aggressive herds. As large numbers of trunkos and thorngrazers are pushed into the drier upland regions, suddenly increased grazing and trampling becomes a stronger factor limiting the spread of the cementrees to new barren habitat. Increased herbivore presence keeps the spire forests from totally dominating the uplands as they might otherwise do, and keeps large stretches of grassland open for grazing between them.

The soggobbler and its lineage is firmly here to stay in the hothouse, but in time its current dominion to the exclusion of other species will be temporary, as specialized predators will soon adapt to hunt prey bigger than anything they have known before. And while some early thorngrazers may have fail to survive their sudden and meteoric rise, others have persisted by moving to new places, and adapting new appearance and ability that gives them a greater competitive edge.

Sirenhorns are a genus of crested thorngrazers which have diverged from the rumbling helmethead in the last 3 million years, as these formerly lowland grazers were driven to spend increasing length of time on higher ground to avoid competing with aggressive early gantuan species - territorial animals that are now big enough to easily kill them - and thanks to having four legs, also able to move much faster moving than those shorter-legged thorngrazers could on just three.

These thorngrazers have now developed longer legs, making them faster runners despite a substantial size of up to 800 lbs, and so able to avoid confrontations with such numerous enemies much more effectively. Their hooves have become smaller to limit contact points with the ground and create a faster gait, with the caveat that they now aren't as useful to distribute their body weight on wet ground. They are now poorly-adapted to live in the wetlands their ancestors did and, visit them only rarely.

The spiral sirenhorn is now bison-like herd animal of drier grassland and open spire forest habitats that stands 5-6 feet at the shoulder. While it has become is a thinner-legged far animal adapted to run better than earlier thorngrazers, this animal is still fairly robust, with a huge head and paired tusks useful for defense. The tooth-horns on the face have reduced in size and number and except for these tusks are now limited to a smattering of small nodules above the mouth. These thorngrazers are now almost totally vegetarian, with more than 95% of the diet being vegetation, mostly grass and low-growing bushes, and their stomachs reflect a more specialized state to focus on plant foods with the bypass that allowed earlier species to readily consume large quantities of meat becoming vestigial. 

Sirenhorns have now evolved larger and more elaborate nasal horns from their sinuses which are used to create extremely loud sometimes musical calls - especially when herds chorus together in harmony. Both sexes have crests and so both can sing, however in males they are larger and accompanied by bright colors and display markings. The horns of males of the spiral sirenhorn are elaborate and curved like a french horn, and for the same reason; by spiraling instead of going straight out, the sound passing through the hollow pipe can continue to resonate in a smaller space. This gives the spiral sirenhorn an extremely loud, deep and resonant call that carries for miles over the landscape. Herds often synchronize their calls similarly to some insects like cicadas, with the effect being that the earth shakes and the noise is deafening at close range. To prevent damage to their hearing, the sirenhorn and other crested thorngrazers have evolved muscles to completely seal their ears closed while vocalizing. 

Above: an audio recording of a chorus of distant spiral sirenhorns synchronizing their calls.