Tergum

Tergites (with lateral paranota) of a polydesmid millipede

A tergum (Latin for "the back"; plural terga, associated adjective tergal) is the dorsal portion of an arthropod segment other than the head. The anterior edge is called the base and posterior edge is called the apex or margin. A given tergum may be divided into hardened plates or sclerites commonly referred to as tergites.^[1]^:20 So, for example, in a thoracic segment, the tergum may be divided into an anterior notum and a posterior scutellum. Lateral extensions of a tergite are known as paranota (Greek for "alongside the back") or carinae (Latin for "keel"), exemplified by the so-called flat-backed millipedes of the order Polydesmida.

In crustaceans, the tergum is known as a pleuron when it overhangs the insertion of the limb on each side as a free plate.

In contrast to the tergum, the ventral portion of a segment is called the sternum.

Examples

Abdominal tergum (divided into several tergites) of a bee

A tergite of this wasp is labeled 19

Thoracic tergites of various trilobites

7 sclerites distinctly visible on the back of a pregnant scorpion

Footnotes

↑ McCafferty (1983).

References

McCafferty, W.Patrick (1983). Aquatic entomology: the fishermen's and ecologists' illustrated guide to insects and their relatives. Jones & Bartlett Publishers, ISBN

0867200170, ISBN 978-0-86720-017-1. Accessed here through Google Books on 08 Jan 2010.

This article is issued from Wikipedia - version of the Friday, March 25, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.