Resupinus

Resupinus is a term used in biological terminology rather than a formally recognized taxon. It functions as a descriptive adjective in taxonomic names to indicate an inverted or turned-back morphology, rather than to designate a separate genus or other rank. In practice, the descriptor signals a habit or orientation of a organism or its structures rather than a distinct evolutionary lineage.

Etymology of resupinus traces to Latin, where resupinus means turned back or inverted, derived from resupinare “to turn back,” with re- meaning back and supinus meaning lying on the back. The word appears in scientific names and descriptions to convey a particular orientation of organs, surfaces, or growth forms.

Usage in taxonomy and morphology is descriptive rather than classificatory. In mycology, closely related terms describe crust-like fungi whose spore-bearing surfaces face outward or downward against the substrate; similar descriptive usage may occur in plant, algal, or paleobotanical contexts to note inversion or unusual orientation. The use of resupinus in a name does not itself imply a separate evolutionary group or a formal rank; it is a descriptive qualifier that can help communicate specific morphological information.

See also: resupinate, resupination, morphology, taxonomy.