Isopoda

Isopoda is an order of crustaceans within the class Malacostraca, consisting of a diverse group of primarily small, dorsoventrally flattened animals. The name is derived from the Greek for "equal feet," a reference to the generally similar pairs of legs that extend along the body. Most isopods have seven pairs of thoracic legs, a broad, segmented abdomen (pleon) with pleopods, and no protective carapace over the head, a combination that supports a wide range of body forms.

Isopods occupy a broad array of habitats. They are found in marine, freshwater, and terrestrial environments. Marine forms range from free-living scavengers and predators to highly adapted parasites. Terrestrial isopods, especially the woodlice in the suborder Oniscidea, are detritivores that live in damp habitats and help decompose leaf litter and other organic matter.

Reproduction and life history are generally sexual, with females bearing eggs in a brood pouch formed by oostegites under the abdomen. The eggs hatch into manca juveniles, representing direct development.

Taxonomy and diversity: Isopoda includes several suborders such as Asellota, Cymothoida, Phreatoidea, and Oniscidea (terrestrial woodlice). The order comprises thousands of described species, with a long fossil record dating back to the Carboniferous period.

Isopods play important roles in many ecosystems as detritivores, predators, and, in some lineages, parasites. Their presence spans a wide range of environments, making them a notable component of aquatic and terrestrial food webs.