Condylostylus is a mostly tropical genus found in the Americas, Africa, and the Oriental Region. The group is most diverse in the Neotropics, but there are many species found in the Afrotropical Region, with most in South Africa or Madagascar, sometimes both. The C. pateraeformis group is easily recognizable with practice and is the most common Condylostylus (and Sciapodinae) found in South Africa.
The C. pateraeformis group is diagnosed in males by the modified wing venation and markings. Vein M1+2 is rather sinuate, bending into cell dm, and the forked vein M1 is almost straight as it goes towards the wing apex, only bending slightly (Fig. 1E, Grichanov 2020). Additionally, males of this species group have long cerci (Fig. 1F) and often have flattened fore tarsi or tibiae (Fig. 1D).
Most of the species require genitalia to confirm, but C. pateraeformis s. str. is easy to diagnose by the strong bend in M1+2 before the fork (compare Fig. 1E to Fig. 2).
iNaturalist observations: https://www.inaturalist.org/observations?taxon_id=1526471
Key to species in: Grichanov, Igor Ya. (2020): New species of Condylostylus Bigot (Diptera: Dolichopodidae) from Comoros Madagascar, Tanzania and South Africa, with key to Afrotropical species. Zootaxa 4830 (1): 62-74, DOI: 10.11646/zootaxa.4830.1.2
Additional details in: Grichanov, I.Y. (1998). New data on Sciapodinae (Diptera: Dolichopodidae) with a revised catalogue and keys to Afrotropical species of the subfamily. Bullein de l'Institut Royal des Sciences Naturelles de Beligque (Entomologie) 68: 79-130.
Fig. 1:
Condylostylus gavryushini
Fig. 2:
Condylostylus pateraeformis
