Notopleuron

Definition

A thoracic pleurite located at the posterior end of the transverse suture on the mesonotum of insects, particularly conspicuous in Diptera. The notopleuron lies lateral to the scutum and typically bears one or more pairs of stiff bristles (notopleural setae) that are important taxonomic characters in fly identification. Its size, shape, and setation pattern vary among families and are routinely used in dichotomous keys.

Etymology

Greek notos (back, dorsum) + pleuron (side, rib)

Example

In Tachinidae, the number and arrangement of notopleural bristles—commonly two anterior and two posterior—help distinguish genera such as Tachina from closely related groups.

Related Terms

• pleuron
• Mesonotum
• Scutum
• transverse suture
• notopleural bristle
• dipteran morphology

Usage Notes

The term is most frequently encountered in dipteran taxonomy, where notopleural setae are a standard character in family-level and generic keys. In other insect orders, the homologous region may be less distinctly differentiated or termed differently; some authors restrict "notopleuron" to Diptera. The plural "notopleura" refers to the paired structures on either side of the thorax. When describing setation, entomologists typically specify anterior and posterior notopleural bristles separately.