Serina: Dwarf Skuggernaut

The last skulossus species thus created (unless someone chooses to sponsor another one), this is the fabled insular pygmy species. I'm sure everyone could've seen that coming from the name on the family tree. That said, it's still quite large, because the landmass it inhabits is no Far Side island, it's the quite large Trang Island, where it is by far the largest endemic beastie.

This here may not look like it, but these are one and the same species, the tall and gracile, forest-dwelling male, and the massive and squat, hippo-like female. Males live in herds and are high browsers, while females are largely territorial and are primarily grazers. It is by far the most extreme sexual dimorphism of any skuorc in terms of both appearance and behaviour (unless I forgot some species with more sexual dimorphism because there sure are a lot of them). Males have colourful heads and long neck spines for identification amongst members of the herd, while females, being mostly solitary, have less need for such contrasting markings Retaining only their inflatable sinuses for threat displays and mating calls.

Females compete with one another for males, which are the sex which decides on mates in this species; females can fertilize their brood with the sperm of multiple males at once, largely nullifying male-on-male competition (hence why they can afford to be much smaller than females and more lightly built). Young dwarf skuggernauts lean towards the leaner build of the males, existing as rather generalist mid-level browsers/grazers before becoming more distinct during a stage of puberty-like growth. Technically speaking, adult males of the species exhibit a form of paedomorphism, retaining the more slender build of juveniles even when full-grown, so it is no surprise that young of the species resemble them more.

These descended from a (possibly) now-extinct population population of Trilliontree Island skuggernaut, one of which migrated north towards the mainland, evolving into the humungous greater skuggernaut, while another migrated south, making it across the stretch of wider and deeper seawater to find themselves on Trang Island. With no large predators to threaten them, they have much reduced armour compared to other skulossi species, and with less competition they've evolved to exploit a number of niches depending on their sex and age, maximizing their success.

I included the female skuggernaut alongside the other Trang Island animals parade just for comparison, but the pictures weren't drawn at the same scale so the detail is a lot fuzzier there.