Phymatothynnus (specimen #042)
Workbook
Collected in Malaise trap (GMP66365) during the week 19th-26th September 2026 (specimen ID #042)
THYNNINAE: Tachynomyini: Phymatothynnus nitidus ‘complex’
Having worked through the various options, I am confident that this is Phymatothynnus. The genus is known from our local region, and meets the diagnostic criteria described by Brown (2025).
Specimen #042 looks very near Phymatothynnus nitidus, which Brown noted is a species complex. Indeed, images of an unidentified species labelled Ph. nr. nitidus (Brown 2025, Fig. 307e,g) look an exact match (see below).
The following is my justification for excluding other options among the Thynnidae and Tiphiidae.
Thynninae: Tachynomyini: Phymatothynnus
Family THYNNIDAE, based on:
3 submarginal cells & frons produced above antennal sockets (so not Tiphiidae: Tiphiinae)
Subfamily THYNNINAE, based on:
frons produced above antennal sockets (so NOT Anthoboscinae)
forewing with distinct 1r vein (so NOT Myzininae)
forewing with 2m-cu meeting SCIII (so NOT Diamminae)
Tribe Tachynomyini most likely, based on:
hypopygium rounded, with minute apical spine (unlike all Rhagigasterini except Eirone)
vertex not lengthened (unlike most Eirone)
clypeal carina simple (not branched, V or Y-shaped) (so NOT Rhagigasterini)
forewing with 3rd interval distinctly shorter than 2nd interval of M, & shorter than half length 2r-m (so NOT Thynnini)
apical margin of clypeus narrow (unlike most Thynnini)
forewing with distinct 1r vein, almost complete (so NOT Iswaroidini & unlike most Agriomyini)
six apical segments of antennae strongly arcuate (so NOT Neozeleboria, Pentazeleboria of tribe Agriomyini)
On the above diagnostic characters alone, I can’t exclude all species of Agriomyini. There are several other genera known to occur in our region (far south eastern NSW and/or Vic), including: Aelothynnus; Agriomyia; Aluacothynnus; Chilothynnus; Zeleboria. While most of these have coloured markings, some species are all black. Also, some species have simple, rounded hypopygium as seen in #042.
However, Phymatothynnus (Tachynomyini) is a good match, including the following diagnostic features:
Antennal shape: the apical 6 or more segments are strongly arcuate.
Hypopygium: there is a distinct notch basal notch on the lateral margin.
And the Phymatothynnus nitidus complex in particular looks very convincing.
References
Brown, G. 2025. Revision of the Australian Thynnidae and Tiphiidae (Hymenoptera). Zootaxa 5681 (1): 001-862 https://doi.org/10.11646/zootaxa.5681.1.1
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