Formal-description
Guides
Undescribed
undescribed taxon, undescribed species
An undescribed taxon refers to any organism that has been discovered but not yet formally described and named according to established nomenclatural codes. These taxa lack official scientific names, though temporary informal designations are commonly used in practice. The phenomenon spans all major organismal groups, with particularly high prevalence in insects, fungi, and tropical invertebrates. Modern molecular techniques have dramatically accelerated discovery of undescribed diversity, revealing cryptic species that appear morphologically identical but are genetically distinct. The interval between discovery and formal description averages 13–21 years, creating a substantial backlog known as the 'taxonomic impediment.'