Sophie Shepherd requested: “Predator and prey from an alternate Mesozoic where archosaurs and cynodonts never displace dicynodonts as the dominant terrestrial vertebrates. Lystrosaurus-descendants conquer the world!”
Well into an alternate Jurassic, long after the Great Dying, the descendants of the opportunistic survivor Lystrosaurus are thriving. Cynodonts and rauisuchian-like archosaurs still saw decent success as large predators during this world’s Triassic, but the extinction at the end of that period wiped most of them out, and now the lystrarch dicynodonts are the dominant land vertebrates.
The most common herbivorous lystrarchs are big bulky Lisowicia-like forms, but in open savanna-like habitats smaller fast-running deer-like forms like Diablocervops shepherdi are starting to diversify.
Standing around 1m tall at the shoulder (~3’3″), Diablocervops has particularly elaborate facial ornamentation, with bosses on its snout, pointed brow horns, and long pronged horns flaring out from its cheekbones. These structures only develop towards maturity but aren’t sexually dimorphic, used for visual displays and in head-pushing contests to establish dominance hierarchies within herds.
It lacks teeth, and grinds mouthfuls of food against its tough palate before swallowing, also using a gizzard-like stomach chamber with gastroliths to further process tough vegetation.
Meanwhile, following the loss of the former archosaur and cynodont predators, Dakorhynchus gorgoides is part of a new lineage of predatory lystrarchs descended from small pig-like omnivorous burrowers that had remained quite similar to their Lystrosaurus ancestors for much of the Triassic.
Around 4m long (~13′), it’s built rather like a large monitor lizard or crocodilian, with a low-slung semi-erect posture and hairless pebbly leathery skin. It’s an ambush predator that lunges with short bursts of speed, grappling with its well-muscled forelimbs and using slashing strikes from its hooked beak and short pointed tusks to subdue prey.