Pusillum

Pusillum is a Latin adjective used in biological nomenclature as a species epithet. It originates from pusillus, meaning “very small” or “tiny.” In the binomial name of an organism, pusillum is the second, or specific, epithet, not a standalone name.

In taxonomy, the epithet pusillum is declined to agree with the gender of the genus. The neuter form pusillum is used with neuter genera, while the masculine form pusillus and the feminine form pusilla are used with masculine and feminine genera, respectively. This agreement follows the standard rules of Latin grammar applied in botanical and zoological naming.

The epithet pusillum is widely employed across many taxonomic groups, including plants, fungi, and animals. Its purpose is typically to indicate a comparatively small size relative to related species within the same genus or lineage. Because many unrelated taxa can have the same epithet, pusillum does not denote close evolutionary relationships by itself; it reflects a descriptive attribute of a single species within its respective genus.

Usage notes emphasize that epithets are specific to the genus they accompany and can be reused across different genera. Therefore, a species named pusillum in one genus is not necessarily related to a species named pusillum in another.

See also: binomial nomenclature, Latin grammar in scientific naming, pusilla, pusillus.