pygidium
Sign in to saveright|thumb|222px|Diagram showing the location of the Cephalon (arthropod head)|cephalon, [[thorax and pygidium of a trilobite.]] The pygidium (: pygidia) is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. In groups other than insects, it contains the anus and, in females, the ovipositor. It is composed of fused body segments, sometimes with a tail, and separated from thoracic segments by an articulation.
Article
7 sectionsContents
- Chelicerates
- Trilobites
- Insects
- Other uses
- See also
- References
- External links
right|thumb|222px|Diagram showing the location of the Cephalon (arthropod head)|cephalon, [[thorax and pygidium of a trilobite.]] The pygidium (: pygidia) is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. In groups other than insects, it contains the anus and, in females, the ovipositor. It is composed of fused body segments, sometimes with a tail, and separated from thoracic segments by an articulation.
==Chelicerates== In arachnids, the pygidium is formed by reduction of the last three opisthosomal segments to rings where there is no distinction between tergites and sternites. A pygidium is present in Palpigradi, Amblypygi, Uropygi, Schizomida, Ricinulei and in the extinct order Trigonotarbida. It is also present in early fossil representatives of horseshoe crabs.