Reniform

Definition

Kidney-shaped; having a rounded outline with a distinct concave indentation on one side, resembling the profile of a kidney. In arthropod morphology, the term describes eyespots, markings, sclerites, or other structures that are broader than long with a medial or posterior notch. The reniform spot (or reniform stigma) on the forewings of many Noctuidae moths is a classic diagnostic character, typically a dark, kidney-shaped marking located between the orbicular spot and the postmedial line.

Etymology

Latin ren, kidney + -form, shape

Example

In many owlet moths (Noctuidae), the forewing bears three characteristic spots: the orbicular (round), reniform (kidney-shaped), and claviform (club-shaped), with the reniform spot often serving as a key identification feature between species.

Synonyms

• kidney-shaped

Related Terms

• Orbicular
• claviform
• ocellus
• stigma
• maculation
• wing pattern
• eyespot

Usage Notes

In entomology, 'reniform' is most commonly encountered in lepidopteran wing morphology, where it contrasts with orbicular (circular) and claviform (elongate). The term is also applied to kidney-shaped eyes in some arachnids and crustaceans, and to various sclerites and markings in other arthropod groups. It should not be confused with 'cordate' (heart-shaped, with the indentation at the base) or 'orbicular' (circular).