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, 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 were elongated, and included sharp piercing stylets, and possibly a sucking pump-like organ. Unlike modern sucking insects, such as the
Hemipterans, 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'' is estimated to have 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
Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...
assemblage of basal palaeodictyopteroidean insects, rather than a clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
, because they gave rise to other insect orders. They range in time from the Middle Carboniferous
The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...
(late Serpukhovian or early Bashkirian
The Bashkirian is in the International Commission on Stratigraphy geologic timescale the lowest stage (stratigraphy), stage or oldest age (geology), age of the Pennsylvanian (geology), Pennsylvanian. The Bashkirian age lasted from to Mega annu ...
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 251.902 Mya. It is the s ...
.
References
External links
Paleodictyoptera
at the Tree of Life project (list of taxa)
Further reading
* Carpenter, F. M. 1992. Superclass Hexapoda. Volume 3 of Part R, Arthropoda 4; '' Treatise on Invertebrate Paleontology'', Boulder, Colorado, Geological Society of America.
*
*
{{Taxonbar, from=Q136109
Carboniferous insects
Extinct insect orders
Permian insects
Pennsylvanian first appearances
Lopingian extinctions
Palaeodictyopteroidea