Meganeura

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Meganeura
Meganeura as it appeared in Walking with Monsters
Meganeura as it appeared in Walking with Monsters
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Superorder: Odonatoptera
Order: Protodonata
Family: Meganeuridae
Genus: Meganeura
Species: M. monyi
Binomial name
Meganeura monyi
(C. Brongniart, 1893)

Meganeura monyi was a prehistoric insect of the Carboniferous period (300 million years ago), resembling and related to the present-day dragonfly. With a wingspan of more than 75 cm (2.5 feet) wide, it was the largest known flying insect species to ever appear on Earth. (The Permian Meganeuropsis permiana is another contender). It was predatory, feeding on other insects and even small amphibians.

Fossils were discovered in the Stephanian Coal Measures of Commentry in France in 1880; in 1885, French paleontologist Charles Brongniart described and named the fossil. Another fine fossil specimen was found in Bolsover, Derbyshire, in 1979. The holotype is housed in the Muséum National d'Histoire Naturelle, Paris.

M. americana, discovered in Oklahoma in 1940, is represented by the largest complete insect wing ever found; it is conserved in the Harvard Museum of Natural History.[1]

Controversy has prevailed as to how insects of the Carboniferous period were able to grow so large. The way oxygen is diffused through the insect's body via its tracheal breathing system puts an upper limit on body size, which prehistoric insects seem to have well exceeded. It was originally proposed (Harlé & Harlé, 1911) that Meganeura was only able to fly because the atmosphere at that time contained more oxygen than the present 20%. This theory was dismissed by fellow scientists, but has found approval more recently through further study into the relationship between gigantism and oxygen availability [2] If this theory is correct, these insect giants would have been perilously susceptible to falling oxygen levels and certainly could not survive in our modern atmosphere. The word Meganeura means "large-veined", referring to the network of veins on the wings.

Contents

Meganeura is a scientific periodical about fossil insects.[3].

  1. ^ "Dragonfly: the largest complete insect wing ever found", Harvard Magazine November-December 2007:112.
  2. ^ Gauthier Chapelle and Lloyd S. Peck (May 1999). "Polar gigantism dictated by oxygen availability" (in English). Nature 399: 114-115. doi:10.1038/20099. “Oxygen supply may also have led to insect gigantism in the Carboniferous period, because atmospheric oxygen was 30-35% (ref. 7). The demise of these insects when oxygen content fell indicates that large species may be susceptible to such change. Giant amphipods may therefore be among the first species to disappear if global temperatures are increased or global oxygen levels decline. Being close to the critical MPS limit may be seen as a specialization that makes giant species more prone to extinction over geological time.” 
  3. ^ {http://www.ub.es/dpep/meganeura/meganeura.htm Meganeura.

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