Pterygota

Definition

A subclass of Insecta comprising all winged insects and those lineages that have secondarily lost wings. Pterygota is defined by the presence of wings in adults (or their evolutionary derivation from winged ancestors) and is traditionally divided into two major groups based on wing articulation and metamorphic mode: Palaeoptera (mayflies and dragonflies, with wings held vertically or outstretched and unable to fold flat over the abdomen) and Neoptera (all remaining winged insects, with wings that fold longitudinally over the back). Within Neoptera, the group is further split by developmental strategy into Endopterygota (complete metamorphosis with pupal stage) and Exopterygota (incomplete metamorphosis with gradual nymphal development). The subclass contrasts with Apterygota, the primitively wingless insects (silverfish and allies).

Etymology

From Greek pterygōtos, 'winged', neuter plural of pterygōtós; from pteryx, 'wing'.

Example

The Blue Morpho butterfly (Morpho spp.) belongs to Pterygota as a member of Endopterygota, having complete metamorphosis and functional wings as an adult; conversely, fleas (Siphonaptera) and lice (Psocodea) are also Pterygota despite being wingless as adults, having descended from winged ancestors.

Synonyms

• winged insects

Related Terms

• Apterygota
• Neoptera
• Palaeoptera
• Endopterygota
• Exopterygota
• Holometabola
• Hemimetabola
• Insecta
• Hexapoda

Usage Notes

The term is used in two distinct taxonomic contexts: (1) the insect subclass described here, and (2) a genus of tropical trees in Malvaceae (formerly Sterculiaceae), which is unrelated. In entomological usage, Pterygota includes many secondarily wingless groups—fleas, lice, some crickets, some beetles, and worker ants—so 'winged insects' is a functional rather than absolute description. The precise phylogenetic placement of Palaeoptera relative to Neoptera remains debated, with some analyses suggesting paraphyly of Palaeoptera. The clade basal Pterygota is sometimes used to refer specifically to Ephemeroptera (mayflies) as the sister group to all other Pterygota.