Atergum (Latin for "the back";pl.:terga, associated adjectivetergal) is thedorsal ('upper') portion of anarthropod segment other than the head. Theanterior edge is called the 'base' and posterior edge is called the 'apex' or 'margin'. A given tergum may be divided into hardened plates orsclerites commonly referred to astergites.[1]
In athoracic segment, for example, the tergum may be divided into an anteriornotum and a posteriorscutellum. Lateral extensions of a tergite are known asparanota (Greek for "alongside the back") orcarinae (Latin for "keel"), exemplified by the flat-backed millipedes of the orderPolydesmida.
Kinorhynchs have tergal and sternal plates too, though seemingly not homologous with those of arthropods.[2]
Tergo-tergal is astridulatory mechanism in which fine spines of the abdominal tergites are rubbed together to produce sound.[3] This process is known as abdominal telescoping.[3]
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