Meganeuropsis

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Meganeuropsis
Temporal occurrence
Artinskium or Kungurium
approx. 280 million years
Locations

Kansas and Oklahoma, USA

Systematics
Arthropod (arthropoda)
Insects (Insecta)
Flying insects (Pterygota)
Meganisoptera
Meganeuropsis
Scientific name
Meganeuropsis
Carpenter , 1939

Meganeuropsis is an extinct genus of insects. It belongs to the group of Meganisoptera (alternative name Protodonata, "giantdragonflies"), an extinct group that forms the parent group or a sister group of the recent dragonflies, but compared to these had numerous original features ( plesiomorphies ). The species Meganeuropsis permiana is generally considered to be the largest winged insect species that has ever lived.

species

Two species have been described within the genus, both based on finds from the Wellington Formation, which had been deposited in Unterperm .

According to David A. Grimaldi and Michael S. Engel , both names are synonymous , a possibility that the first person to describe it, Frank M. Carpenter, had already considered. If one follows this view, the genus only includes the first-named species.

Description and finds

Meganeuropsis permiana was described after two wing fragments that were found separately but closely spaced by Carpenter himself in the limestone quarry of Elmo. The first fragment comprises the wing base and part of the proximal wing, the second a section of the wing center. Since parts of the vein contain overlapping areas, they cannot have been sections of the same wing. It seems likely that the fragments come from a fore and a hind wing. The shape of the entire wing was estimated by drawing on the wing outline of the giant dragonfly Meganeura monyi from the fragments obtained. On this basis, Carpenter reconstructs a wing length of 330 millimeters, from which he derives a wingspan of 710 millimeters. Of the second species, Meganeuropsis americana, there is a fossil of an almost completely preserved wing that was still 280 millimeters long, its total length is estimated to be 305 millimeters. Today it is on display at the Harvard Museum of Natural History. Although the total length is estimated to be somewhat smaller, it is still the largest fossil insect wing that has actually been preserved. In addition, there is a second well-preserved wing and a good dozen other fragments assigned to this species, all of which were found by GORaasch in Midco, Oklahoma. Here, in 2000, Roy Beckemeyer discovered another hind wing fragment that is now in the Johnston Geology Museum at Emporia State University, Emporia, Kansas.

The genus Meganeuropsis is considered to be closely related to the European Meganeura according to the wing veins , both are often united in one family Meganeuridae. The family is difficult and uncertain to differentiate from other families of the giant dragonflies, so that some authors dispense with the assignment to a family as a precaution. In addition to its size, the genus can be distinguished from the other American giant dragonflies by the enlarged precostal field in the wing, which extends to the middle of the wing. The genus is differentiated from the related genus according to some details of the wing veins. Fossils from parts of the body other than the wings have never been found.

Location

The Wellington Formation is a series of Unterperm rocks that are exposed over a length of approximately 270 kilometers in Kansas and Oklahoma, from Elmo in the north to Midco near Perry in the south. In the middle sections, the formation is covered by a thick layer of loess and almost never exposed above ground. Almost 200 fossil insect species have been described from the formation, which makes it one of the most diverse Permian insect sites in the world. The formation reaches 214 meters in thickness and includes marine, brackish and limnic (deposited in freshwater) sediments, including anhydrite and rock salt deposits. The fossil finds come from the so-called Carlton limestone near the base of the formation, which is only a few meters thick. Contrary to the often expressed impression that the fauna of that time was mainly characterized by giant insects, most of the species found are relatively small (average wingspan about 22 millimeters), and only a few reached the size of giant dragonflies. 10 of a total of only 13 species with wingspans over 50 millimeters belonged to this group. Little is known about their way of life, in particular it is unclear whether their larvae, like those of the recent dragonflies, lived in the water. For the adult giant dragonflies, a predatory diet is considered guaranteed. Since no vertebrates capable of flying existed at that time, they were probably top predators of the fauna of that time.

At the time of the deposition, the region was close to the equator. The limestone was deposited in a coastal plain on the edge of a large inland salt lake. Fossil gill-pods , which resemble the recent genus Triops , were found in the lake sediments ; it is generally assumed that the water is quite hostile to life. The flying insects were probably blown in and perished here.

Individual evidence

  1. ^ A b Frank Morton Carpenter: The Lower Permian Insects of Kansas. Part 8: Additional Megasecoptera, Protodonata, Odonata, Homoptera, Psocoptera, Protelytroptera, Plectoptera, and Protoperlaria. In: Proceedings of the American Academy of Arts and Sciences. 73 (3), 1939, pp. 29-70. JSTOR 25130151
  2. ^ Roy J. Beckemeyer: The Permian Insect Fossils of Elmo, Kansas. In: Kansas School Naturalist. 46 (1), 2000. (online)
  3. ^ Frank Morton Carpenter: Lower Permian Insects from Oklahoma. Part 1: Introduction and the Orders Megasecoptera, Protodonata, and Odonata. In: Proceedings of the American Academy of Arts and Sciences. 76 (2), 1947, pp. 25-54. JSTOR 20023497
  4. ↑ D. Grimaldi, MS Engel: Evolution of the Insects. Cambridge University Press, 2005, ISBN 0-521-82149-5 , p. 175.
  5. ↑ DRAGONfly. The largest complete insect wing ever found. In: Harvard Magazine. November / December 2007.
  6. ^ Roy J. Beckemeyer: Hind Wing Fragments Of Meganeuropsis (Protodonata: Meganeuridae) from the Lower Permian of Noble County, Oklahoma. In: Bulletin of American Odonatology. 9 (3/4), 2006, pp. 85-89.
  7. ^ André Nel, Günther Fleck, Romain Garrouste, Georges Gand, Jean Lapeyrie, Seth M. Bybee, Jakub Prokop: Revision of Permo-Carboniferous griffenflies (Insecta: Odonatoptera: Meganisoptera) based upon new species and redescription of selected poorly known taxa from Eurasia . In: Palaeontographica Department A. 289, Delivery 4–6, 2009, pp. 89–121.
  8. ↑ Michael S. Engel: Megatypus parvus spec. nov., a new giant dragonfly from the Lower Permian of Kansas (Protodonata: Meganeuridae). In: Odonatologica. 27 (3), 1998, pp. 361-364.
  9. ↑ The Entomofauna of the Lower Permian fossil insect beds of Kansas and Oklahoma, United States. In: African Invertebrates. 48 (1), April 2007, pp. 23-39.
  10. ^ RR West, KB Miller, WL Watney: The Permian System in Kansas. (= Kansas Geological Survey Bulletin. 257). 2010, ISBN 978-1-58806-333-X .