Monotypic

Definition

Of a taxon: containing only one immediately subordinate taxon. A monotypic genus contains a single species; a monotypic species lacks subspecies or other infraspecific ranks. The term is rank-neutral and contrasts with polytypic taxa, which contain multiple subordinate units. In zoological usage, "monospecific" or "unispecific" are sometimes preferred for genera; botanical nomenclature additionally recognizes the special case where genus and species are described simultaneously.

Etymology

From Greek monos (single, alone) + typos (type, pattern)

Example

The myrmecophilous beetle genus Tetradonia is monotypic, containing only the single species T. clypeata described from army ant colonies in Central America.

Synonyms

• monospecific (for genera, preferred by some zoologists)
• unispecific (for genera)

Related Terms

• polytypic
• monotypic genus
• monotypic species
• Holotype
• type species
• infraspecific rank

Usage Notes

Distinguish from monophyletic (descent-based) and monomorphic (morphology-based). The term describes taxonomic structure, not evolutionary history or phenotypic uniformity. A monotypic family may contain one genus with many species, or one genus with one species; context clarifies which level is monotypic. In entomology, monotypic genera are common in poorly sampled groups or relict lineages, and their status may change with revisionary work.