Palaeodictyoptera
Encyclopedia
The Palaeodictyoptera are an extinct order of medium-sized to very large, primitive Palaeozoic paleopterous
insects.
, in front of the first pair of wings. Although the paranota are technically not wings, the Palaeodictyoptera are whimsically called "six-winged insects". The actual wings are often boldly marked, the colour patterns evident even in fossils.
The mouthparts
were elongated, and included sharp piercing stylets, and possibly a sucking pump-like organ. Unlike modern sucking insects, such as the Hemiptera
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 ectoparasites, or predators.
Some types attained huge size. For example, Mazothairos had a wingspan of about 55 centimetres (21.7 in). 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
n insects, rather than a clade
, because they gave rise to other insect orders. They range in time from the Middle Carboniferous
(late Serpukhovian
or early Bashkirian
in age) to the late Permian
.
Paleoptera
The name Palaeoptera has been traditionally applied to those primitive groups of winged insects that lacked the ability to fold the wings back over the abdomen as characterizes the Neoptera...
insects.
Overview
They were characterised by beak-like mouthparts, similarity between fore- and hind wings, and an additional pair of winglets (large paranotal lobes) on the prothoraxProthorax
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 are the pronotum , the prosternum , and the propleuron on each side. The prothorax never bears wings in extant insects, though some fossil groups possessed...
, in front of the first pair of wings. Although the paranota are technically not wings, the Palaeodictyoptera are whimsically called "six-winged insects". The actual wings are often boldly marked, the colour patterns evident even in fossils.
The mouthparts
Insect mouthparts
Insects exhibit a range of mouthparts, adapted to particular modes of feeding. The earliest insects had chewing mouthparts...
were elongated, and included sharp piercing stylets, and possibly a sucking pump-like organ. Unlike modern sucking insects, such as the Hemiptera
Hemiptera
Hemiptera is an order of insects most often known as the true bugs , comprising around 50,000–80,000 species of cicadas, aphids, planthoppers, leafhoppers, shield bugs, and others...
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 ectoparasites, or predators.
Some types attained huge size. For example, Mazothairos had a wingspan of about 55 centimetres (21.7 in). Another distinctive feature was the presence of unusually long cerci
Cercus
Cerci are paired appendages on the rear-most segments of many arthropods, including insects and arachnids but not crustaceans. Cerci often serve as sensory organs, but they may also be used as weapons or copulation aids, or they may simply be vestigial structures.Typical cerci may appear to be...
, about twice the length of the abdomen.
The Palaeodictyoptera are a paraphyletic assemblage of basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
palaeodictyopteroidea
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 group of herbivorous insects...
n insects, rather than a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
, because they gave rise to other insect orders. They range in time from the Middle Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
(late Serpukhovian
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 328.3 Ma tot 318.1 Ma...
or early Bashkirian
Bashkirian
The Bashkirian is in the ICS geologic timescale the lowest stage or oldest age of the Pennsylvanian, the youngest subsystem of the Carboniferous...
in age) to the late Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
.
External links
- Paleodictyoptera at the Tree of Life project (list of taxa)