Myriapoda

Myriapoda is a subphylum of arthropods that includes four living groups: centipedes (Chilopoda), millipedes (Diplopoda), pauropods (Pauropoda), and symphylans (Symphyla). They are characterized by elongated, segmented bodies with many legs, a single pair of antennae on the head, and a predominantly terrestrial lifestyle. Although the groups differ in size and habits, they share a common body plan and a lineage related to other mandibulate arthropods.

Anatomy and lifestyle: The trunk consists of numerous somites bearing legs; centipedes have one pair of legs per body segment and a pair of modified front legs (forcipules) for prey capture, making them active predators. Millipedes have two pairs of legs per apparent body segment (diplosegments) and are mostly detritivores or herbivores. Pauropods and symphy­lans are smaller, often eyeless, living in soil or leaf litter where they feed on decaying matter or microinvertebrates. Respiration is primarily through a network of tracheae with spiracles.

Reproduction and development: Most myriapods lay eggs. Juveniles resemble smaller adults and grow by molts, adding segments and legs as they mature; centipedes and diplopods have different patterns of leg addition due to segment fusion.

Ecology and evolution: Myriapods are important in soils and leaf litter as decomposers, predators, and prey. They have a long fossil record, with early terrestrial relatives appearing in the Silurian and giving rise to the diversity seen today.