Nymphomyia

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Nymphomyia
Systematics
Class : Insects (Insecta)
Holometabola
Order : Fly (Diptera)
Subordination : Mosquitoes (Nematocera)
Family : Nymphomyiidae
Genre : Nymphomyia
Scientific name of the  family
Nymphomyiidae
Tokunaga, 1932
Scientific name of the  genus
Nymphomyia
Tokunaga , 1932

Nymphomyia is a genus of mosquitoes with a primitive morphology and an uncertain systematic position. It is the only genus of the ( monotypical ) family Nymphomyiidae . Nymphomyia species live in North and East Asia and North America. The larvae are aquatic (water-living).

features

Adults

Nymphomyiidae are delicate, slender, pale yellowish colored mosquitoes with a body length of about 1.5 to 2.5 millimeters. The wings are long and very slender, with greatly reduced veins, their area is enlarged by a dense border of hair bristles, the hairs being longer than the width of the wings.

The head is protruding and prognathic (that is, the mouth opening points forward), it is broad behind and pointed towards the front. The mouthparts are rudimentary and functionless, the animals no longer take up food in the imaginal stage . The complex eyes consist of approx. 35 to 40 ommatidia, they are broadly separated on the upper side of the head and approached or connected to one another on the lower side. Behind the complex eyes there is another, single-lensed eye, which may be traced back to the larval eyes (stemmata). The antennae are short, they consist of three recognizable links. The base limb (scapus) and reversible limb (pedicellus) are followed by a flagellum consisting of a single, stalked, club-shaped limb flattened towards the tip, which is indistinctly curled at the base by rows of tiny bristles. The mouthparts consist only of a tongue-shaped, soft appendix that carries two small papillae.

The thorax is long, slender and cylindrical, the middle segment ( mesothorax ) with the wings is the longest. The wings consist of a strip-shaped to triangular flap with reduced veins, which has a long hairline all around. Their length reaches about 2 millimeters. The edge vein (costa) is clear and surrounds the entire edge of the wing. Subcosta and Radius are very short and flow into the Costa near the base of the wing. The radius artery Rs is curved and ends in the basal third of the wing in the costa, other arteries are very indistinct. Behind the wings, as is typical for Diptera, there is a pair of relatively large swinging bulbs ( holders ). The legs are long and slender, with elongated hips (coxa) and long and thin thigh rings (trochanters). The legs (femora) and splints (tibiae) appear to be divided into two parts by a membranous region. The tarsus consists of five elongated limbs, with clear, strongly curved claws at the end. All three pairs of legs are designed the same. The species can hardly walk, after a short distance they catapult themselves into the air through violent body curvatures and prefer to move in flight.

The abdomen is elongated, cylindrical and only slightly sclerotized. Nine segments can be seen. It has dense, very short hair and few bristles on the rear edges of the segments. Stigmas are completely absent. The third to seventh segment can have small appendages (paraterga) on the sides. The mating organs are located at the end of the abdomen of the males. Gonocoxite, cerci and the tergite of the last segments have grown together to form a paired structure, the elongated, evertable aedeagus is hardly sclerotized. The females carry long, one- or two-segment cerci, a spermatheca is not recognizable.

Larvae and pupae

The brightly colored larvae are narrow and elongated, slightly compressed at the sides, they reach about 2 millimeters in length. The clearly sclerotized head capsule has long, one-part antennae and a pair of distinct, darker-colored larval eyes (stemmata). The three fuselage segments have no attachments. Of the nine abdominal segments, the first seven and the ninth have strikingly long, paired pseudopods. The mouthparts are complex, the mandibles wide with a serrated crest, the labium wide, flat and serrated at the end, each with a wide paralabial plate. There are four larval stages. The elongated, cylindrical pupa has sparsely bristled bristles, it has neither recognizable stigmas nor respiratory horns or other respiratory organs.

Way of life and life cycle

Nymphomyia species are rare, but can reach very high densities locally in suitable habitats. The larvae of Nymphomyia live at the bottom of rapidly flowing, cold mountain streams up to around 3000 m above sea level. They sit on the surface of stones that are often covered with moss. Individual species are less common in spring rivulets or small rivers with stony bottoms. The larvae scrape the growth ( periphyton ) of diatoms and bacteria from the stone surfaces with their mouthparts or feed on detritus . After four larval stages, the larvae pupate in the same habitat, with the pupae often preferring areas that are somewhat calmer. After hatching, the winged adults swim to the surface of the water, which they pierce with violent, beating movements. The adults form cloud-like swarms over the water, preferably in the evening hours, which in Japan can be so dense that the opposite bank is no longer recognizable. Within the swarms, neighboring individuals fly towards each other in a helical movement, mating takes place in flight. The pairs land on stones on the banks of the water and then climb back into the water, usually still coupled to one another, where the females lay their eggs. Often they apparently shed their wings for this. As far as is known, the adults die immediately after they lay eggs. There are obviously populations with one or two generations ( bivoltin ) per year. Hibernation occurs as a larva or as an egg. At least in Japan and Siberia two species have been found next to each other in the same running water, but mostly only one species occurs in each habitat.

distribution

The first species of the genus Nymphomyia was found in Japan ( Hokkaidō ). There are now also finds from the Russian Far East, Mongolia and the Himalayas. The discovery in Canada in 1961 was considered a big surprise at the time, and numerous finds are now known from eastern Canada to the northern USA. Individual observations are also made much further south, in Hong Kong, Malaysia and Borneo. The family is distributed across the Holarctic , but is absent in Europe. It is believed that it died out here in the Ice Age. In 1995 a fossil species, Nymphomyia succina , was found in the Baltic and Bitterfeld amber , which proves an earlier occurrence in Europe. The current distribution of the genus is considered a relic distribution, it consists of island-like, often widely separated (disjoint) sub-areas.

Phylogeny, taxonomy, systematics

The type species of the genus and family is Nymphomya alba , which was discovered in 1932 by Masaaki Tokunaga in Japan. The finds from North America and the Himalayas were described in two other genera ( Palaeodipteron Ide, 1965, Felicitomyia Kevan, 1970), but both were synonymous with Nymphomyia by Gregory W. Courtney . The family thus only includes one genus. Seven to nine species are currently recognized.

Earlier investigators saw in the family, due to the numerous plesiomophic characteristics of the very larva-like adults, the most primitive of all two-winged animals. Boris Borissowitsch Rodendorf put them in their own suborder Nymphomyiomorpha. A common classification puts them together with the families Deuterophlebiidae and Blephariceridae in a suborder Blephariceromorpha. Others see relationships to the equally enigmatic family Axymyiidae or the suborder of the Culicomorpha . The position of the Nymphomyiidae in the system is currently unclear.

A close relationship is to the family through many similar morphological features Strashilidae suspected long as parasites of pterodactyls were or feathered dinosaurs, but probably a similar aquatic lifestyle had as Nymphomyia species. This extinct family is only documented by fossil finds from the Jura of China and Russia.

Individual evidence

  1. ^ A b c Gregory W. Courtney (1994): Biosystematics of the Nymphomyiidae (Insecta: Diptera): Life History, Morphology, and Phylogenetic Relationships. Smithsonian contributions to zoology; no. 550. 41 pages
  2. ↑ D. Keith McE. Kevan & Felicity EA Cutten: Nymphomyiidae. In JF McAlpine, BV Peterson, GE Shewell, HJ Teskey, JR Vockeroth, DM Wood (editors): Manual of Nearctic Diptera. Vol. 1. Research Branch, Agriculture Canada, Monograph No. 27, 1981. Canadian Government Publishing Center, ISBN 0-660-10731-7 .
  3. ↑ Toyohei Saigusa, Takeyuki Nakamura, Seiji Sato (2009): Insect Mist - swarming of Nymphomyia species in Japan. Fly Times 43: 2-8.
  4. ↑ Gregory W. Courtney: Insecta: Diptera, Nymphomyiidae. In Catherine M. Yule & Yong Hoi Sen (editors): Freshwater Invertebrates of the Malaysian Region. Academy of Sciences Malaysia, 2004. pp. 769-774.
  5. ↑ R. Wagner, C. Hoff One, W. Hoff One (2000): A fossil nymphomyiid (Diptera) from the Baltic and Bitterfeld amber. Systematic Entomology 25: 115-120.
  6. ↑ Lambkin, CL, Sinclair, BJ, Pape, T., Courtney, GW, Skevington, JH, Meier, R., Yeates, DK, Blagoderov, V., Wiegmann, BM (2013): The phylogenetic relationships among infraorders and superfamilies of Diptera based on morphological evidence. Systematic Entomology 38 (1): 164-179. doi: 10.1111 / j.1365-3113.2012.00652.x
  7. ^ Gregory W. Courtney (1991): Phylogenetic analysis of the Blephariceromorpha, with special reference to mountain midges (Diptera: Deuterophlebiidae). Systematic Entomology 16 (2): 137-172. doi: 10.1111 / j.1365-3113.1991.tb00683.x
  8. ↑ Sujatha Narayanan Kutty, Wing Hing Wong, Karen Meusemann, Rudolf Meier, Peter S. Cranston (2018): A phylogenomic analysis of Culicomorpha (Diptera) resolves the relationships among the eight constituent families. Systematic Entomology 43: 434-446. doi: 10.1111 / syen.12285
  9. ↑ Diying Huang, André Nel, Chenyang Cai, Qibin Lin, Michael S. Engel (2013): Amphibious flies and paedomorphism in the Jurassic period. Nature 495: 94-97. doi: 10.1038 / nature11898