Setaceous

Definition

Bearing, resembling, or consisting of setae; bristle-like in form or texture. Used to describe antennae, legs, or other appendages that are slender, segmented, and conspicuously hairlike or bristly, with long fine setae projecting at intervals.

Etymology

From Latin seta (bristle) + -aceous (resembling)

Example

Many ichneumonid wasps have setaceous antennae composed of dozens of slender flagellomeres, each giving rise to fine sensory setae that increase surface area for chemoreception.

Synonyms

• setose
• bristly

Related Terms

• seta
• setose
• pilose
• hirsute
• pubescent
• chaetotaxy
• flagellomere
• Sensillum

Usage Notes

Distinguished from 'pilose' (softly hairy) and 'hirsute' (coarsely hairy) by the specific reference to setae—stiff, often socketed bristles. In antennae, 'setaceous' specifically describes the thread-like, many-segmented form with long setae, contrasting with 'filiform' (thread-like but without conspicuous setae), 'moniliform' (bead-like), or 'clavate' (clubbed). Not to be confused with 'setose,' which describes a surface bearing setae rather than the overall bristle-like form.