Nannochoristidae

Nannochoristidae is a family of scorpionflies with many unusual traits. It is a tiny, relict family of about eight species, with members of the genus Nannochorista occurring in New Zealand, southeastern Australia, Tasmania, and Chile, so is probably of Gondwanan origin. The adults look like scorpionflies with more pointed, elongated wings. Most mecopteran larvae are eruciform, or shaped like caterpillars. Nannochoristid larvae, however, are elateriform, or shaped like wireworm or click beetle larvae. They are also the only entirely aquatic Mecoptera. Wing venation suggests a close relationship to dipterans. They are predatory, primarily on the larvae of aquatic Diptera.

Nannochoristidae Temporal range: Jurassic–Recent PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Mecoptera
Family:	Nannochoristidae Tillyard, 1917
Genera
Microchorista Nannochorista

Some research suggests the nannochoristids are the only holometabolous insects with true larval compound eyes .[1] 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

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).[2][3][4][5]

Panzygothoraca	Panorpida Antliophora   Diptera (true flies)   Mecopteroidea   Nannochoristidae       Mecoptera (scorpionflies, hangingflies) (exc. Boreidae & Nannochoristidae)       Boreidae (snow scorpionflies)     Siphonaptera (fleas)           Amphiesmenoptera   Trichoptera (caddisflies)     Lepidoptera (butterflies and moths)         Hymenoptera (sawflies, wasps, ants, bees)
(part of Endopterygota)

Genera

This list is adapted from the World Checklist of extant Mecoptera species[6] and is complete as of 1997.

• Microchorista Byers, 1974 (one species: New Zealand)
• Nannochorista Tillyard, 1917 (six species: Argentina, Chile, Tasmania, Australia) Koonwarra fossil bed, Australia, Aptian
• †Dahurochorista Sukatsheva 1985 (one species: Ichetuy Formation, Oxfordian, Russia)
• †Dahurolarva Sukatsheva 1985 (one species: Ichetuy Formation, Oxfordian, Russia)
• †Jichoristella Ren 1995
• †Itaphlebia Sukatsheva 1985 Itat Formation, Russia, Bathonian, Daohugou, China, Callovian, Karabastau Formation, Kazakhstan, Oxfordian
• †Namdyrus Sukacheva 1993 Khaya Formation, Russia, Tithonian

References

1. 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.
2. 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.
3. Yeates, David K.; Wiegmann, Brian. "Endopterygota Insects with complete metamorphosis". Tree of Life. Retrieved 24 May 2016.
4. 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. Archived from the original on 2013-01-05.
5. Wiegmann, Brian; Yeates, David K. (2012). The Evolutionary Biology of Flies. Columbia University Press. p. 5. ISBN 978-0-231-50170-5.
6. World Checklist of extant Mecoptera species Nannochoristidae