Oniscidea

Woodlice are terrestrial isopods in the suborder Oniscidea. Their name is derived from being often found in old wood, and from louse, a parasitic insect, although woodlice are neither parasitic nor insects. Other common names include slater, sow bug, and wood pig, common names varying widely by region.

Woodlice are suggested to have colonised land during the late Paleozoic based on molecular clock analysis, though the oldest known fossils are from the mid-Cretaceous period around 100 million years ago. This makes them unusual among the crustaceans, being one of the few lineages to have transitioned into a fully terrestrial environment.