The Pterygota ( grc, πτερυγωτός, pterugōtós, winged) are a subclass of

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...

s that includes the winged insects. It also includes insect orders that are secondarily wingless (that is, insect groups whose ancestors once had wings but that have lost them as a result of subsequent evolution). The pterygotan group comprises almost all insects. The

orders not included are the Archaeognatha (jumping bristletails) and the Zygentoma ( silverfishes and firebrats), two primitively wingless insect orders. Also not included is

Entognatha The Entognatha are a class of wingless and ametabolous arthropods, which, together with the insects, makes up the subphylum Hexapoda. Their mouthparts are entognathous, meaning that they are retracted within the head, unlike the insects. Entog ...

, which consist of three orders no longer considered to be insects:

Protura The Protura, or proturans, and sometimes nicknamed coneheads, are very small (0.6-1.5mm long), soil-dwelling animals, so inconspicuous they were not noticed until the 20th century. The Protura constitute an order of hexapods that were previously ...

, Collembola, and

Diplura The order Diplura ("two-pronged bristletails") is one of three orders of non-insect hexapods within the class Entognatha (alongside Collembola (springtails) and Protura). The name "diplura", or "two tails", refers to the characteristic pair of ...

Systematics

Traditionally, this group was divided into the infraclasses Paleoptera and

Neoptera Neoptera (Ancient Greek ''néos'' (“new”) + ''pterón'' (“wing”)) is a classification group that includes most orders of the winged insects, specifically those that can flex their wings over their abdomens. This is in contrast with the mo ...

. The former are nowadays strongly suspected of being paraphyletic, and better treatments (such as dividing or dissolving the group) are presently being discussed. In addition, it is not clear how exactly the neopterans are related among each other. The Exopterygota might be a similar assemblage of rather ancient

hemimetabolous Hemimetabolism or hemimetaboly, also called incomplete metamorphosis and paurometabolism,McGavin, George C. ''Essential Entomology: An Order-by-Order Introduction''. Oxford: Oxford University Press, 2001. pp. 20. is the mode of development of certa ...

insects among the Neoptera like the Palaeoptera are among insects as a whole. The

holometabolous Holometabolism, also called complete metamorphosis, is a form of insect development which includes four life stages: egg, larva, pupa, and imago (or adult). Holometabolism is a synapomorphic trait of all insects in the superorder Endopterygota. ...

Endopterygota seem to be very close relatives, indeed, but nonetheless appear to contain several clades of related orders, the status of which is not agreed upon. The following scheme uses finer divisions than the one above, which is not well-suited to correctly accommodating the fossil groups.

Infraclass Palaeoptera

(probably paraphyletic) * Ephemeroptera (mayflies) *

Palaeodictyoptera The Palaeodictyoptera are an extinct order of medium-sized to very large, primitive Palaeozoic paleopterous insects. They are informative about the evolution of wings in insects. Overview They were characterized by beak-like mouthparts, used ...

†(extinct) *

Megasecoptera Megasecoptera is a Paleozoic insect order. There are 22 known families of megasecopterans, with about 35 known genera. Overview Like all other paleodictyopteroids, the megasecopterans had sucking mouthparts. The suctorial mouth parts were proba ...

†(extinct) *

Archodonata Archodonata is an extinct order of palaeozoic paleopterous insects, sometimes included in Odonata Odonata is an order of flying insects that includes the dragonflies and damselflies. Members of the group first appeared during the Triassic, th ...

†(extinct) *

Diaphanopterodea The Diaphanopterodea or Paramegasecoptera are an extinct order of moderate to large-sized Palaeozoic insects. They are first known from the Middle Carboniferous (late Serpukhovian or early Bashkirian in age), and include some of the earliest know ...

†(extinct) *

Protodonata Meganisoptera is an extinct order of very large to gigantic insects, informally called griffinflies. The order was formerly named Protodonata, the "proto-Odonata", for their similar appearance and supposed relation to modern Odonata (damselflies ...

or Meganisoptera †(extinct; sometimes included in Odonata) *

Protanisoptera The Odonatoptera are a superorder (sometimes treated as an order) of ancient winged insects, placed in the probably paraphyletic group Palaeoptera. The dragonflies and damselflies are the only living members of this group, which was far more div ...

†(extinct; sometimes included in Odonata) * Triadophlebioptera †(extinct; sometimes included in Odonata) * Protozygoptera or Archizygoptera †(extinct; sometimes included in Odonata) *

Odonata Odonata is an order of flying insects that includes the dragonflies and damselflies. Members of the group first appeared during the Triassic, though members of their total group, Odonatoptera, first appeared in Late Carboniferous. The two com ...

(

dragonflies A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threa ...

and damselflies)

Infraclass Neoptera

Superorder Exopterygota *

Caloneurodea Caloneurodea is an extinct order of polyneopteran neopteran insects in the superorder Orthopterida. The Caloneurodea are known from fossils found in North America, Europe, Russia, and Asia and had a palegeographic range confined to Laurussia. F ...

†(extinct) * Titanoptera †(extinct) * Protorthoptera †(extinct) * Plecoptera (stoneflies) * Embioptera (webspinners) *

Zoraptera The insect order Zoraptera, commonly known as angel insects, contains small and soft bodied insects with two forms: winged with wings sheddable as in termites, dark and with eyes (compound) and ocelli (simple); or wingless, pale and without eyes ...

(angel insects) * Dermaptera (earwigs) * Orthoptera ( grasshoppers, etc.) * Phasmatodea (stick insects – tentatively placed here) * Notoptera (gladiators and ice-crawlers – tentatively placed here) *Proposed superorder Dictyoptera ** Blattodea (cockroaches and termites) **

Mantodea Mantises are an order (Mantodea) of insects that contains over 2,400 species in about 460 genera in 33 families. The largest family is the Mantidae ("mantids"). Mantises are distributed worldwide in temperate and tropical habitats. They ha ...

(mantids) ** Alienoptera †(extinct) *Proposed superorder

Paraneoptera Paraneoptera or Acercaria is a superorder of insects which includes lice (bark lice and true lice), thrips, and hemipterans, the true bugs. It also includes the extinct order Permopsocida, known from fossils dating from the Early Permian to the ...

** Psocoptera (booklice, barklice) **

Thysanoptera Thrips (order Thysanoptera) are minute (mostly long or less), slender insects with fringed wings and unique asymmetrical mouthparts. Different thrips species feed mostly on plants by puncturing and sucking up the contents, although a few are ...

(thrips) **

Phthiraptera Louse ( : lice) is the common name for any member of the clade Phthiraptera, which contains nearly 5,000 species of wingless parasitic insects. Phthiraptera has variously been recognized as an order, infraorder, or a parvorder, as a result of ...

( lice) ** Hemiptera (true bugs) Superorder Endopterygota * Hymenoptera (

ant Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of ...

s, bees, etc.) * Coleoptera (beetles) *

Strepsiptera The Strepsiptera are an order of insects with eleven extant families that include about 600 described species. They are endoparasites in other insects, such as bees, wasps, leafhoppers, silverfish, and cockroaches. Females of most species never ...

(twisted-winged parasites) *

Raphidioptera Snakeflies are a group of predatory insects comprising the order Raphidioptera with two extant families: Raphidiidae and Inocelliidae, consisting of roughly 260 species. In the past, the group had a much wider distribution than it does now; s ...

(snakeflies) * Megaloptera ( alderflies, etc.) * Neuroptera (net-veined insects) *Proposed superorder Mecopteroidea/ Antliophora **

Mecoptera Mecoptera (from the Greek: ''mecos'' = "long", ''ptera'' = "wings") is an order of insects in the superorder Endopterygota with about six hundred species in nine families worldwide. Mecopterans are sometimes called scorpionflies after their lar ...

(scorpionflies, etc.) ** Siphonaptera (

flea Flea, the common name for the order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Adult fleas grow to about long, a ...

s) ** Diptera (true

flies Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced m ...

) ** Protodiptera †(extinct) *Proposed superorder

Amphiesmenoptera Amphiesmenoptera is an insect superorder, established by S. G. Kiriakoff, but often credited to Willi Hennig in his revision of insect taxonomy for two sister orders: Lepidoptera (butterflies and moths) and Trichoptera (caddisflies). In 2017, a t ...

Trichoptera The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the b ...

(

caddisflies The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the ...

) ** Lepidoptera ( butterflies,

moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...

s) Neoptera orders ''

incertae sedis ' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertain ...

'' * Glosselytrodea †(extinct) * Miomoptera †(extinct)

References

External links

{{Authority control Insect taxonomy Arthropod subclasses Extant Pennsylvanian first appearances Dicondylia