The Odonatoptera are a superorder (sometimes treated as an order) of ancient winged insects, placed in the Palaeoptera which probably form a paraphyletic group however. The dragonflies and damselflies are the only living members of this group, which was far more diverse in the late Paleozoic and contained gigantic species, including the griffinflies (colloquially called "giant dragonflies", although they were not dragonflies in the strict sense) of the order Protodonata. This lineage dates back at least to the Bashkirian, not quite 320 million years ago. 
Temporal range: Late Carboniferous - Recent
|The giant griffinfly Meganeura monyi lived some 300 million years ago. It was as large as a crow.|
Campylopterodea Rohdendorf, 1962
There is little consensus about the relationships of the Odonatoptera. What is certain is that they are a clade of winged insects that stands outside the Neoptera. But various authors' analyses have yielded any one of three mutually exclusive phylogenies, or some variant thereof: The least problematic (in a taxonomic sense) view is that the Odonatoptera are the sister taxon of the Ephemeropteroidea (the mayfly lineage), and that the Palaeodictyopteroidea are either their sister taxon or a basal assemblage, all within a monophyletic Palaeoptera. But few recent analyses have supported this. Rather, it seems more and more likely that the Odonatoptera are the sister taxon of the Neoptera, making the "Palaeoptera" paraphyletic. The third view places the mayfly lineage as sister taxon of the neopterans, with the Odonatoptera as most primitive winged insects; it has seen little support in recent decades however.
While the internal subdivision of this superorder is subject to much dispute and far from resolved, at least the coarser divisions seem to be fairly stable by now. Six orders are generally recognized, as well as two families incertae sedis and a further "family" that is almost certainly not monophyletic. Ordered from the most ancestral to the most advanced, these are:
Based on the work of Petrulevičius & Gutierrez 2016.
In some treatments, the Odonata are expanded to include all these taxa with the exception of the "Erasipteridae", Geroptera and Protodonata; this group is treated as an unranked clade Odonatoclada in the scheme used here. Where the Odonata are defined loosely, the term Odonatoidea is used instead of "Odonatoptera".
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 third fossil order was added to the group, the Tarachoptera.Trichoptera and Lepidoptera share a number of derived characters (synapomorphies) which demonstrate their common descent:
Females, rather than males, are heterogametic (i.e. their sex chromosomes differ).
Dense setae are present in the wings (modified into scales in Lepidoptera).
There is a particular venation pattern on the forewings (the double-looped anal veins).
Larvae have mouth structures and glands to make and manipulate silk.Thus these two extant orders are sisters, with Tarachoptera basal to both groups. Amphiesmenoptera probably evolved in the Jurassic. Lepidoptera differ from the Trichoptera in several features, including wing venation, form of the scales on the wings, loss of the cerci, loss of an ocellus, and changes to the legs.Amphiesmenoptera are thought to be the sister group of Antliophora, a proposed superorder comprising Diptera (flies), Siphonaptera (fleas) and Mecoptera (scorpionflies). Together, Amphiesmenoptera and Antliophora compose the group Mecopterida.Archodonata
Archodonata is an extinct order of palaeozoic paleopterous insects, sometimes included in Odonata.Chlorogomphidae
The Chlorogomphidae are a family of Odonata (dragonflies) from the suborder Anisoptera.Corduliidae
The insect family Corduliidae contains the emerald dragonflies or green-eyed skimmers. These dragonflies are usually black or dark brown with areas of metallic green or yellow, and most of them have large, emerald-green eyes. The larvae are black, hairy-looking, and usually semiaquatic. Members of this family include the baskettails, emeralds, river cruisers, sundragons, shadowdragons, and boghaunters. They are not uncommon and are found nearly worldwide, but some individual species are quite rare. Hine's emerald dragonfly (Somatochlora hineana), for example, is an endangered species in the United States.Dicondylia
The Dicondylia are a taxonomic group (taxon) that includes all insects except the jumping bristletails (Archaeognatha). Dicondylia have a mandible attached with two hinges to the head capsule (dicondyl), in contrast to the original mandible with a single ball joint (monocondyl).Epiprocta
Epiprocta is one of the two extant suborders of the Odonata (the order to which dragonflies and damselflies belong). It was proposed relatively recently, having been created to accommodate the inclusion of the Anisozygoptera. The latter has been shown to be not a natural suborder, but rather a paraphyletic collection of lineages, so it has been combined with the previous suborder Anisoptera, the well-known dragonflies, into the Epiprocta. The old suborder Anisoptera is proposed to become an infraorder within the Epiprocta, whereas the "anisozygopterans" included here form the infraorder Epiophlebioptera.Eumetabola
Eumetabola is an unranked category of Neoptera. Two large unities known as the Paurometabola and Eumetabola are probably from the adelphotaxa of the Neoptera after exclusion of the Plecoptera. The monophyly of these unities appears to be weakly justified.Libelluloidea
Libelluloidea is a superfamily of dragonflies.
A 2007 phylogenetic analysis suggests that this superfamily contains four families:
MacromiidaeSome authors include other families here, including Synthemistidae and the monotypic Neopetaliidae.Meganisoptera
Meganisoptera is an extinct order of very large to gigantic insects, occasionally called griffinflies. The order was formerly named Protodonata, the "proto-Odonata", for their similar appearance and supposed relation to modern Odonata (damselflies and dragonflies). They range in Palaeozoic (Late Carboniferous to Late Permian) times. Though most were only slightly larger than modern dragonflies, the order includes the largest known insect species, such as the late Carboniferous Meganeura monyi, Megatypus, and the even larger early Permian Meganeuropsis permiana, with wingspans of up to 71 centimetres (28 in).
The forewings and hindwings are similar in venation (a primitive feature) except for the larger anal (rearwards) area in the hindwing. The forewing is usually more slender and slightly longer than the hindwing. Unlike the true dragonflies, the Odonata, they had no pterostigma, and a somewhat simpler pattern of veins in the wings.
Most specimens are known from wing fragments only; with only a few as complete wings, and even fewer (of the family Meganeuridae) with body impressions. These show a globose head with large dentate mandibles, strong spiny legs, a large thorax, and long and slender dragonfly-like abdomen. Like true dragonflies, they were presumably predators.
A few nymphs are also known, and show mouthparts similar to those of modern dragonfly nymphs, suggesting that they were also active aquatic predators.Although sometimes included under the dragonflies, the Protodonata lack certain distinctive wing features that characterise the Odonata. Grimaldi & Engel 2005 point out that the colloquial term "giant dragonfly" is therefore misleading, and suggest "griffinfly" instead.Metapterygota
Metapterygota is a clade of winged insects containing order Odonata and Infraclass Neoptera.Myrmeleontoidea
Myrmeleontoidea is a lacewing superfamily in the suborder Myrmeleontiformia.Neoptera
Neoptera 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 more basal orders of winged insects (the "Palaeoptera" assemblage), which are unable to flex their wings in this way.Odonata
Odonata is an order of carnivorous insects encompassing the dragonflies (Anisoptera) and the damselflies (Zygoptera). The Odonata form a clade, which has existed since the Permian.Dragonflies are generally larger, and perch with their wings held out to the sides; damselflies have slender bodies, and hold their wings over the body at rest.Palaeoptera
The name Palaeoptera has been traditionally applied to those ancestral groups of winged insects (most of them extinct) that lacked the ability to fold the wings back over the abdomen as characterizes the Neoptera. The Diaphanopterodea, which are palaeopteran insects, had independently and uniquely evolved a different wing-folding mechanism. Both mayflies and dragonflies lack any of the smell centers in their brain found in Neoptera.Panorpida
Panorpida or Mecopterida is a proposed superorder of Endopterygota. The conjectured monophyly of the Panorpida is historically based on morphological evidence, namely the reduction or loss of the ovipositor and several internal characteristics, including a muscle connecting a pleuron and the first axillary sclerite at the base of the wing, various features of the larval maxilla and labium, and basal fusion of CuP and A1 veins in the hind wings. The monophyly of the Panorpida is also supported by recent molecular data.Paraneoptera
Paraneoptera is a monophyletic superorder of insects which includes four orders, the bark lice, true lice, thrips, and hemipterans, the true bugs. The mouthparts of the Paraneoptera reflect diverse feeding habits. Basal groups are microbial surface feeders, whereas more advanced groups feed on plant or animal fluids.Polythoridae
The Polythoridae are a family of damselflies. They are found in New World tropics. The family contains 58 species.
Subfamilies and genera include:
Protodiptera is an extinct order of insects containing the two genera Permotipula and Permila.Psocodea
Psocodea is a taxonomic group of insects comprising the bark lice, book lice and true lice. It was formerly considered a superorder, but is now generally considered by entomologists as an order. Despite the greatly differing appearance of lice, they are believed to have evolved from within the former order "Psocoptera", which contained the bark lice and book lice. Psocodea contains around 11,000 species, divided among seven suborders.