Proseriata is an order of free-living flatworms in the class Rhabditophora with over 400 species described worldwide.

[1] Proseriate flatworms are minute aquatic organisms, usually with an elongate body.

[2] Most proseriates occur in marine environments, at the coastal zones, and are particularly common in high-energy habitats with medium to coarse sediments, sometimes being the dominant animal group in such areas.

[1] Most proseriates are carnivores or scavengers, but some species are ectoparasitic on marine crustaceans.

As they occur in very high densities in some habitats, they may have a considerable impact on the population of other meiofaunal organisms.