tergite

A tergite is a dorsal sclerite, or hardened plate, that covers a body segment in many arthropods, especially insects and crustaceans. The term comes from the Latin tergum, meaning back. In most arthropods, each body segment bears a dorsal tergite, often paired with lateral pleura (side plates) and ventral sternites on the underside.

Function and structure: Tergites form part of the exoskeleton and provide protection for underlying tissues while serving as attachment sites for muscles that move the segment. They can be rigid or flexibly linked to adjacent plates, and may be modified, reduced, or fused during development. In some lineages, tergites contribute to the formation of a carapace or dorsal shield that covers multiple segments.

In insects, abdominal tergites constitute the dorsal portions of the abdominal segments, while thoracic tergites cover the thorax. Segments are typically designated T1 onward, and species may show variation such as fusion of tergites, segmentation changes, or specialized structures for flight or protection. In crustaceans, the dorsal plates of the body segments are also termed tergites; the carapace, when present, can be derived from the fusion or modification of several anterior tergites.

Related terms: The ventral counterpart is the sternite, and the lateral plates adjacent to tergites are the pleurites. The concept of tergites is fundamental to understanding arthropod segmentation and morphological variation across groups.