Heterogyna

Heterogynaidae is a minor and disputed lineage (only eight described species in a single genus, Heterogyna) of small spheciform wasps occurring in Madagascar, Botswana, Turkmenistan, Oman, the United Arab Emirates, and the Eastern Mediterranean area. The majority are dark in color and range in size from approximately 1.5 to 5.0 mm. Most specimens have been collected in arid climates, but one species from Madagascar is known to occur in a humid forest habitat. Although males have functional wings, heterogynaid females are typically brachypterous, a trait which is unique among spheciform wasps. Wing venation is reduced in both sexes. All species are diurnal, with the exception of H. nocticola. Other aspects of their biology are completely unknown, but details of their morphology have prompted researchers to hypothesize that they may be non-fossorial parasitoids adapted to hunt in tight spaces, such as under tree bark. This is speculative and has not yet been confirmed by actual observations of behavior. It is also possible that modifications of the female metasomal tergum VI and gonostyli may represent a unique prey transport mechanism, but this is also unconfirmed.

Heterogyna
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Bembicidae
Tribe:	Nyssonini
Genus:	Heterogyna Nagy, 1969
Species
Heterogyna botswana Heterogyna fantsilotra Heterogyna kugleri Heterogyna madecassa Heterogyna nocticola Heterogyna polita Heterogyna protea Heterogyna ravenala

The Heterogynaidae were historically considered the sister taxon to the remainder of the Apoidea, but recent studies utilizing molecular characters do not support this hypothesis. While monophyly of the genus is strongly supported, it is now considered to be related to the Crabronidae^[1] or, most recently, a lineage within the Bembicidae.^[2]

References

1. Branstetter, Michael G.; Danforth, Bryan N.; Pitts, James P.; Faircloth, Brant C.; Ward, Philip S.; Buffington, Matthew L.; Gates, Michael W.; Kula, Robert R.; Brady, Seán G. (2017). "Phylogenomic Insights into the Evolution of Stinging Wasps and the Origins of Ants and Bees". Current Biology. 27 (7): 1019–1025. Bibcode:2017CBio...27.1019B. doi:10.1016/j.cub.2017.03.027. PMID 28376325.
2. Manuela Sann, Oliver Niehuis, Ralph S. Peters, Christoph Mayer, Alexey Kozlov, Lars Podsiadlowski, Sarah Bank, Karen Meusemann, Bernhard Misof, Christoph Bleidorn and Michael Ohl (2018) Phylogenomic analysis of Apoidea sheds new light on the sister group of bees. BMC Evolutionary Biology 18:71. doi:10.1186/s12862-018-1155-8

• Day, M.C. (1984). "The enigmatic genus Heterogyna Nagy (Hymenoptera: Sphecidae; Heterogyninae)". Systematic Entomology. 9 (3): 293–307. Bibcode:1984SysEn...9..293D. doi:10.1111/j.1365-3113.1984.tb00054.x. S2CID 84501607.
• Goulet, H., Huber, J.T. (1993) Hymenoptera of the World. Agriculture Canada Research Branch, publication 1894/E. 668pp.
• Ohl, M. & Bleidorn, C. (2006) "The phylogenetic position of the enigmatic wasp family Heterogynaidae based on molecular data, with a new description of a new, nocturnal species (Hymenoptera: Apoidea)". Systematic Entomology, 31, 321–337.