Posterus

Posterus is a Latin adjective meaning “following, posterior, later,” and it is used in biological nomenclature as an epithet to indicate a posterior position or feature. The term derives from Latin posterus, related to post, and is typically Latinized in scientific names.

In taxonomy, posterus is most often encountered as a specific epithet rather than as a standalone genus name. It signals that a character is located toward the rear of the organism or appears in a posterior arrangement relative to related taxa. The descriptor may apply to anatomy, such as a posterior process, spine, or limb, or to broader aspects of an organism’s morphology or spatial distribution within a genus.

Because posterus is descriptive rather than taxonomically informative, many unrelated species across diverse groups can bear the epithet without implying close evolutionary relationships. The exact meaning is guided by the context of the original description and the particular feature the author intended to highlight.

The use of posterus reflects a broader practice in taxonomy of employing Latin adjectives to convey positional or morphological information succinctly. It exemplifies how epithets function as tools for distinguishing species based on observable traits rather than signaling phylogenetic relationships.

See also: binomial nomenclature, Latin grammar in taxonomy, species epithet, Latin adjectives in biological names.