Gystens

Gystens is a fictional creature appearing in the speculative evolution project "Xenotheria" created by artist and writer Mark Witton. Within the context of this project, Gystens are depicted as large, herbivorous mammals adapted to a semi-aquatic lifestyle in the wetlands and coastal regions of a future Earth. They are characterized by their broad, paddle-like feet, thick skin, and a specialized digestive system capable of processing tough plant matter.

The evolutionary lineage of Gystens is theorized to stem from a group of terrestrial mammals that gradually adapted to exploit abundant aquatic vegetation. Their morphology suggests a balance between terrestrial locomotion for foraging and swimming for both escape from predators and access to food resources. Gystens are typically portrayed as solitary or living in small family groups, feeding primarily on reeds, aquatic plants, and algae. Their slow metabolism and reliance on vegetation indicate a largely peaceful existence, with their primary defense mechanisms being their size and their ability to retreat into water. The Xenotheria project often uses Gystens as an example of how existing mammalian body plans could evolve to fill ecological niches previously occupied by other groups, such as large aquatic herbivores.