NOSpezies

NOSpezies is a term used in speculative biology and science fiction to denote life forms that defy standard species boundaries. It is not an official taxonomic category in biology; rather, it serves as a thought experiment or worldbuilding device to explore how species are defined and delineated.

The concept covers organisms whose reproduction, genetics, or morphology do not neatly align with standard species concepts, including those with extensive horizontal gene transfer, significant phenotypic plasticity, or life stages that do not co-occur. In fiction and theoretical discussions, NOSpezies often describe chimeric or hybrid lifeforms, alien biologies, or digital-physical hybrids that challenge classification.

In practice, NOSpezies is a tool for examining taxonomy's limits. It highlights the gaps between theoretical concepts of species and the realities of evolution, symbiosis, and synthetic biology. It is sometimes used to critique overly rigid taxonomies and to illustrate why many scientists maintain multiple, overlapping criteria for delimiting species.

The term is mainly used in speculative contexts and is not part of formal biology. See also discussions of species concepts and related ideas in taxonomy, including the biological, morphological, and phylogenetic species concepts.