Epipharynx

Definition

In insects, a median, often flexible or sclerotized lobe on the inner (dorsal) surface of the labrum that extends into the preoral cavity; it typically bears sensilla and may assist in food manipulation, taste reception, or forming a channel for liquid uptake. In some groups, the epipharynx is fused with or closely associated with the hypopharynx, forming a functional mouthpart complex.

Etymology

From Greek epi- (upon, above) + pharynx (throat), referring to its position superior to the pharyngeal region of the foregut.

Example

In adult Lepidoptera, the epipharynx forms part of the suctorial proboscis assembly, working with the galeae to create the food canal; in grasshoppers (Orthoptera), the epipharynx is a more rigid plate that helps direct chewed plant material toward the mouth.

Related Terms

• Labrum
• hypopharynx
• Cibarium
• preoral cavity
• superlinguae
• Mandible
• Maxilla

Usage Notes

Distinguished from the hypopharynx, which arises from the floor of the mouth (ventral), whereas the epipharynx is derived from the labrum (dorsal). The term is sometimes used loosely for any dorsal pharyngeal wall structure, but in entomology it specifically refers to the labral derivative. Not to be confused with the unrelated polychaete species name Pionosyllis epipharynx.