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 to pierce plant tissues for feeding. There is a similarity between their fore- and hindwings, and an additional pair of winglets on the

prothorax The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum ( dorsal), the prosternum ( ventral), and the propleuron ( lateral) o ...

, in front of the first pair of wings. They are known as "six-winged insects" because of the presence of a pair of wings on each of the thoracic segments. Their winglets provide clues to the origins of the first insect wings. The

mouthparts Mouthparts may refer to: * The parts of a mouth ** Arthropod mouthparts The mouthparts of arthropods have evolved into a number of forms, each adapted to a different style or mode of feeding. Most mouthparts represent modified, paired append ...

were elongated, and included sharp piercing stylets, and possibly a sucking pump-like organ. Unlike modern sucking insects, such as the

Hemiptera Hemiptera (; ) is an order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from to arou ...

ns, the mouthparts were held vertically below the head, or projected forwards. They probably used these organs to suck juices from plants, although some may have been

ectoparasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

s, or predators. Some types attained huge size. For example, ''

Mazothairos ''Mazothairos'' (from Mazo, derived from its location of Mazon Creek and θαιρός, ''thairos'', meaning 'hinge' in Greek) is an extinct genus of very large insect from the Carboniferous period. It was a member of the order Palaeodictyoptera. ...

'' had a wingspan of about . Another distinctive feature was the presence of unusually long cerci, about twice the length of the abdomen. The Palaeodictyoptera are a paraphyletic assemblage of basal

palaeodictyopteroidea The Palaeodictyopteroidea or Paleodictyopterida are an extinct superorder of Palaeozoic beaked insects, characterised by unique mouthparts consisting of 5 stylets. They represent the first important terrestrial herbivores, and the first major gr ...

n insects, rather than a clade, because they gave rise to other insect orders. They range in time from the Middle Carboniferous (late

Serpukhovian The Serpukhovian is in the ICS geologic timescale the uppermost stage or youngest age of the Mississippian, the lower subsystem of the Carboniferous. The Serpukhovian age lasted from Ma to Ma. It is preceded by the Visean and is followed b ...

or early Bashkirian in age) to the late

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last ...

References

External links

Paleodictyoptera
at the Tree of Life project (list of taxa)

Overview

References

External links

Further reading