Nannochoristidae is a family of scorpionflies with many unusual traits. It is a tiny, relict family with a single extant genus, Nannochorista, with eight species occurring in New Zealand, southeastern Australia, Tasmania, Argentina and Chile. Due to the group's distinctiveness from other scorpionflies, it is sometimes placed in its own order, the Nannomecoptera. Some studies have placed them as the closest living relatives of fleas.[1] Most mecopteran larvae are eruciform, or shaped like caterpillars. Nannochoristid larvae, however, are elateriform, and have elongated and slender bodies. The larvae are aquatic, which is unique among mecopterans. The larvae are predatory, hunting on the beds of shallow streams, primarily on the larvae of aquatic Diptera like chironomids.[2] The adults are thought probably to be adapted to liquid feeding, likely on flower nectar and/or the juice of fruits. Adults of Australian and South American species are often found in habitats like the edges of streams, lakes, as well as montane bogs. Australian species have been observed visiting the foliage and flowers of Leptospermum (tea trees).[3]

Nannochoristidae
Temporal range: Middle Jurassic–Recent
Nannochorista philpotti
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Mecoptera
Family: Nannochoristidae
Tillyard, 1917
Genera

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Fossils indicate that Nannochoristidae formerly had a wider distribution, being present in the Northern Hemisphere during the Jurassic and Early Cretaceous.[4]

Some research suggests the nannochoristids are the only holometabolous insects with true larval compound eyes.[5] All other eyed larvae have stemmata, which are structurally different from adult compound eyes with ommatidia. This is unusual, since most adult features are present as imaginal discs in larvae and not formed until pupation. The presence of compound eyes in nannochoristid larvae suggests the timing of the development of adult features can be initiated earlier in development, which has important implications for insect evolutionary development.

Phylogeny

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The cladogram of external relationships, based on a 2008 DNA and protein analysis, shows the family as a clade, sister to the Siphonaptera (fleas) and rest of Mecoptera, and more distantly related to the Diptera (true flies) and Mecoptera (scorpionflies).[6][7][8][9]

Antliophora

Diptera (true flies)  

Mecoptera

Nannochoristidae

Pistillifera (scorpionflies, hangingflies)

 

Boreidae (snow scorpionflies)  

Siphonaptera (fleas)  

A more recent study in 2021 found Nannochoristidae to be the sister group to fleas, with strong support.[1]

Antliophora

Diptera (true flies)  

Boreidae (snow scorpionflies, 30 spp.)  

Nannochoristidae (southern scorpionflies, 8 spp.)

Siphonaptera (fleas, 2500 spp.)  

Pistillifera (scorpionflies, hangingflies, 400 spp.)  

Genera

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After Cao et al. 2022.[10]

References

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  1. ^ a b Tihelka, Erik; Giacomelli, Mattia; Huang, Di-Ying; Pisani, Davide; Donoghue, Philip C. J.; Cai, Chen-Yang (2020-12-21). "Fleas are parasitic scorpionflies". Palaeoentomology. 3 (6): 641–653–641–653. doi:10.11646/palaeoentomology.3.6.16. hdl:1983/8d3c12c6-529c-4754-b59d-3abf88a32fc9. ISSN 2624-2834. S2CID 234423213.
  2. ^ Fraulob, Maximilian; Wipfler, Benjamin; Hünefeld, Frank; Pohl, Hans; Beutel, Rolf G. (March 2012). "The larval abdomen of the enigmatic Nannochoristidae (Mecoptera, Insecta)". Arthropod Structure & Development. 41 (2): 187–198. doi:10.1016/j.asd.2011.11.001. PMID 22309703.
  3. ^ Palmer, Christopher (2010). "Diversity of feeding strategies in adult Mecoptera". Terrestrial Arthropod Reviews. 3 (2): 111–128. doi:10.1163/187498310x519716. ISSN 1874-9828.
  4. ^ LIU, NAN; Zhao, Yunyun; REN, DONG (2010-04-07). "Two new fossil species of Itaphlebia (Mecoptera: Nannochoristidae) from Jiulongshan Formation, Inner Mongolia, China". Zootaxa. 2420 (1): 37. doi:10.11646/zootaxa.2420.1.3. ISSN 1175-5334.
  5. ^ Melzer, R. R.; H. F. Paulus & N. P. Kristensen (1994). "The larval eye of nannochoristid scorpionflies (Insecta, Mecoptera)". Acta Zoologica. 75 (3): 201–208. doi:10.1111/j.1463-6395.1994.tb01207.x.
  6. ^ Whiting, Michael F.; Whiting, Alison S.; Hastriter, Michael W.; Dittmar, Katharina (2008). "A molecular phylogeny of fleas (Insecta: Siphonaptera): origins and host associations". Cladistics. 24 (5): 677–707. CiteSeerX 10.1.1.731.5211. doi:10.1111/j.1096-0031.2008.00211.x. S2CID 33808144.
  7. ^ Yeates, David K.; Wiegmann, Brian. "Endopterygota Insects with complete metamorphosis". Tree of Life. Retrieved 24 May 2016.
  8. ^ Whiting, Michael F. (2002). "Mecoptera is paraphyletic: multiple genes and phylogeny of Mecoptera and Siphonaptera". Zoologica Scripta. 31 (1): 93–104. doi:10.1046/j.0300-3256.2001.00095.x. S2CID 56100681. Archived from the original on 2013-01-05.
  9. ^ Wiegmann, Brian; Yeates, David K. (2012). The Evolutionary Biology of Flies. Columbia University Press. p. 5. ISBN 978-0-231-50170-5.
  10. ^ Cao, Yizi; Lin, Xiaodan; Shih, Chungkun; Ren, Dong (2022-06-24). "Two new species of Itaphlebia (Insecta, Mecoptera, Nannochoristidae) from the late Middle Jurassic of China". ZooKeys (1108): 175–188. doi:10.3897/zookeys.1108.85378. ISSN 1313-2970. PMC 9848664. PMID 36760696.