| Megasecoptera Temporal range: | |
|---|---|
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| Adult of Mischoptera nigra (a) and reconstructions of early (b) and late (c) larvae of Mischoptera douglassi | |
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| Restoration of Corydaloides scudderi | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Superorder: | † Palaeodictyopteroidea |
| Order: | † Megasecoptera Brongniart, 1885 |
Megasecoptera is a Paleozoic insect order. There are 22 known families of megasecopterans, with about 35 known genera.
Like all other paleodictyopteroids, the megasecopterans had sucking mouthparts. The suctorial mouth parts were probably used to pierce plant casings and extract high-quality plant materials, such as spores and pollen.
Unlike some earlier insects, megasecopterans bore two pairs of wings, which were nearly of the same size. The wings probably were held horizontally, as in dragonflies (Odonata, Anisoptera). The wing bases tend to be very slender and petiolated, as in damselflies (Odonata, Zygoptera). The body was usually long and thin, although the genus Protohymen was rather stouter and shorter than a typical megasecopteran. Another distinctive feature was the presence of a number of fine processes projecting from the body, which in some cases could be longer than the body itself, forming long fringes on the insect's underside. [1]
During their relatively brief period of existence, the Megasecoptera were rather successful. It has been estimated that this insect order accounted for 50% of the insect biomass in some locations, but the available evidence might be misleading.[ citation needed ].
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.
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 threatens dragonfly populations around the world. Adult dragonflies are characterized by a pair of large, multifaceted compound eyes, two pairs of strong, transparent wings, sometimes with coloured patches, and an elongated body. Many dragonflies have brilliant iridescent or metallic colours produced by structural colouration, making them conspicuous in flight. An adult dragonfly's compound eyes have nearly 24,000 ommatidia each.
Damselflies are flying insects of the suborder Zygoptera in the order Odonata. They are similar to dragonflies, which constitute the other odonatan suborder, Anisoptera, but are smaller and have slimmer bodies. Most species fold the wings along the body when at rest, unlike dragonflies which hold the wings flat and away from the body. An ancient group, damselflies have existed since at least the Lower Permian beginning about 299 million years ago, and are found on every continent except Antarctica.
The Pterygota are a subclass of insects that includes all winged insects and the orders that are secondarily wingless.
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, which are unable to flex their wings in this way.
Megaloptera is an order of insects. It contains the alderflies, dobsonflies and fishflies, and there are about 300 known species.
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.
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. They range in Palaeozoic 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 and the even larger early Permian Meganeuropsis permiana, with wingspans of up to 71 centimetres (28 in).
The most recent understanding of the evolution of insects is based on studies of the following branches of science: molecular biology, insect morphology, paleontology, insect taxonomy, evolution, embryology, bioinformatics and scientific computing. It is estimated that the class of insects originated on Earth about 480 million years ago, in the Ordovician, at about the same time terrestrial plants appeared. Insects may have evolved from a group of crustaceans. The first insects were landbound, but about 400 million years ago in the Devonian period one lineage of insects evolved flight, the first animals to do so. The oldest insect fossil has been proposed to be Rhyniognatha hirsti, estimated to be 400 million years old, but the insect identity of the fossil has been contested. Global climate conditions changed several times during the history of Earth, and along with it the diversity of insects. The Pterygotes underwent a major radiation in the Carboniferous while the Endopterygota underwent another major radiation in the Permian.
Pantala flavescens, the globe skimmer, globe wanderer or wandering glider, is a wide-ranging dragonfly of the family Libellulidae. This species and Pantala hymenaea, the "spot-winged glider", are the only members of the genus Pantala. It was first described by Johan Christian Fabricius in 1798. It is considered to be the most widespread dragonfly on the planet with good population on every continent except Antarctica although rare in Europe. Globe skimmers make an annual multigenerational journey of some 18,000 km ; to complete the migration, individual globe skimmers fly more than 6,000 km —one of the farthest known migrations of all insect species.
The Calopterygidae are a family of damselflies, in the suborder Zygoptera. They are commonly known as the broad-winged damselflies, demoiselles, or jewelwings. These rather large damselflies have wingspans of 50–80 mm, are often metallic-coloured, and can be differentiated from other damselflies by the broader connection between the wings and the body, as opposed to the abrupt narrowing seen in other damselfly families. The family contains some 150 species.
The Lestidae are a rather small family of cosmopolitan, large-sized, slender damselflies, known commonly as the spreadwings or spread-winged damselflies.
Insect wings are adult outgrowths of the insect exoskeleton that enable insects to fly. They are found on the second and third thoracic segments, and the two pairs are often referred to as the forewings and hindwings, respectively, though a few insects lack hindwings, even rudiments. The wings are strengthened by a number of longitudinal veins, which often have cross-connections that form closed "cells" in the membrane. The patterns resulting from the fusion and cross-connection of the wing veins are often diagnostic for different evolutionary lineages and can be used for identification to the family or even genus level in many orders of insects.
The Himalayan relict dragonfly is one of four species of Epiprocta in the family Epiophlebiidae. They have at one time been classified as a suborder Anisozygoptera, considered as intermediate between the dragonflies and the damselflies, partly because the hind wings and fore wings are very similar in size and shape, and partly because the insect at rest holds them back over the body as damselflies do. These attributes now are known to be misleading however; the genus Epiophlebia shares a more recent ancestor with dragonflies and became separated from other Anisoptera in and around the uplifting Himalayas.
The Pseudostigmatidae are a family of tropical damselflies, known as helicopter damselflies, giant damselflies, or forest giants. The family includes the largest of all damselfly species. They specialize in preying on web-building spiders, and breed in phytotelmata, the small bodies of water held by plants such as bromeliads.
Megaloprepus caerulatus is a damselfly of the Forest Giant family within the Coenagrioniae family. Giant damselflies were previously recognized as their own family, Pseudostigmatidae. M. caerulatus is found in wet and moist forests in Central and South America. It has the greatest wingspan of any living damselfly or dragonfly, up to 19 centimeters (7.5 inches) in the largest males. Its large size and the markings on its wings make it a conspicuous species; a hovering Megaloprepus has been described as a "pulsating blue-and-white beacon". M. caerulatus is the only species in genus Megaloprepus.
The Odonatoptera are a superorder 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 diverse in the late Paleozoic and contained gigantic species, including the griffinflies of the order Meganisoptera. This lineage dates back at least to the Bashkirian, not quite 320 million years ago.
The Tarsophlebiidae is an extinct family of medium-sized fossil odonates from the Upper Jurassic and Lower Cretaceous period of Eurasia. They are either the most basal member of the damsel-dragonfly grade ("anisozygopteres") within the stem group of Anisoptera, or the sister group of all Recent odonates. They are characterized by the basally open discoidal cell in both pairs of wings, very long legs, paddle-shaped male cerci, and a hypertrophied ovipositor in females.
Odonata are insects with an incomplete metamorphosis (hemimetabolous). The aquatic larva or nymph hatches from an egg, and develops through eight to seventeen instars before leaving the water and emerging as the winged adult or imago.
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