pygidial
/paɪˈdʒɪdiəl/
adjective
- Relating to the pygidium, the rear body segment or tail plate of certain arthropods (such as trilobites, beetles, and some crustaceans).
- The beetle's pygidial glands release a defensive chemical when it is threatened.
- The entomologist examined the pygidial region of the insect under a microscope.
- Fossil trilobites are often identified by the shape of their pygidial shield.