Projioida

Projioida is a fictional taxonomic group created for speculative biology and science fiction settings. It is not recognized by formal taxonomic authorities, and there is no consensus about its members, phylogenetic placement, or real-world distribution.

In common fictional depictions, projioida comprises small, planktonic organisms with simple, sac-like bodies. They are described as having limited differentiated tissues, chambered internal canals, and pseudopod-like projections for locomotion and feeding. Reproduction is typically asexual, through division or budding, with occasional spore-like propagules in extended life cycles.

Projioida is usually placed in aquatic environments, both freshwater and marine, occupying micro- to mesoplankton size ranges. They are depicted as either primary producers or detritivores, feeding by diffusing nutrients across membranes or by filtering suspended particles, and they may form loose aggregations or biofilms.

Because projioida is a fictional construct, its taxonomic position is unstable and varies by author. It is sometimes used as a teaching analogy to illustrate how real groups are defined and distinguished, or as a convenient plot element to explore ecological interactions in aquatic settings.

In related contexts, projioida appears alongside other fictional groups in works of speculative biology and worldbuilding.