Kiariidae

Kiariidae is a fictional family of marine arthropods created for speculative biology and worldbuilding. In the imagined taxonomy, Kiariidae is a small family characterized by a shield-like carapace, a compact cephalothorax, and a laterally compressed body plan adapted to life in shallow seas. The type genus is Kiaria. In typical worldbuilding classifications, Kiariidae sits within the order Kiariopoda, within the larger crustacean lineage, though placement varies between authors and settings.

The family is described as containing two described genera, Kiaria and Kaostia, with several species assigned within Kiaria. Representative species include Kiaria parva, the type species, Kiaria grandis, and Kaostia littoralis. Members are depicted as having a semicircular dorsal carapace, a series of articulating thoracopods, and a short, segmented abdomen ending in a simple telson. Eye structure is usually reduced or stalked, depending on the depiction, and sensory antennae are prominent.

Ecology and distribution in the fiction place Kiariidae in temperate to tropical coastal shelves, on soft substrates and among seagrass beds. They may be detritivores or small scavengers, with planktonic larvae that enable wider dispersal in certain worlds. The fossil record is often used in-world to anchor their historical presence, with occasional mentions in Cambrian to Paleozoic strata, depending on the setting.

While Kiariidae has no standing in real-world taxonomy, it serves as an example of how taxonomic concepts are used in fiction to organize imagined biodiversity.