Eristalinus (Eristalodes) barclayi & E. (E. ) quinquelineatus - the lesser known Stripe-eyed Lagoon Flies

According to recent studies assembling the mitogenomes of Afrotropical species of Eristalinus, E. barclayi, E. quinquelineatus and E. fuscicornis form a species complex. „These results either question the taxonomic value of the morphological characters used to distinguish the three species, or illustrates a recent divergence, ongoing speciation, hybridization, or introgression.“ (Gontran Sonet, Yannick De Smet, Min Tang, Massimiliano Virgilio, Andrew Donovan Young, Jeffrey H. Skevington, Ximo Mengual, Thierry Backeljau, Shanlin Liu, Xin Zhou, Marc De Meyer, and Kurt Jordaens. First mitochondrial genomes of five hoverfly species of the genus Eristalinus (Diptera: Syrphidae). Genome. 62(10): 677-687. https://doi.org/10.1139/gen-2019-0009 )

Nonetheless, the two species E. barclayi and E. quinquelineatus are here presented follwing Bezzi's (1915) key and descriptions. A good number of specimens from South Africa fit into the descriptions of the species while there are some specimens that do not fit in very well. There are interesting specimens from Zimbabwe posted on iNat that are possibly such „hybrids“.

Both species can be easily told from the well known similar Stripe-eyed Lagoon Fly Eristalinus (Eristalodes) taenipos by the stong, contrasting, uniterrupted thorax stripes - blurred stripes, usually interrupted by the suture in E. taenipos

The easiest way to identify the two species is to compare them with photos on Pindip and type photos on GBIF.
E. barclayi:
Syntype male: https://www.gbif.org/occurrence/1055607406
Syntype female: https://www.gbif.org/occurrence/1836107228
https://www.pindip.org/eristalinus-barclayi

E. quinquelineatus:
Holotype female: https://www.gbif.org/occurrence/1055443362#occurrencePage_media
https://www.pindip.org/eristalinus-quinquelineatus

Both species occur all over Southern Africa and beyond. (However, it appears that E. barclayi has a soft spot for Cape Town gardens).

Publicerat 30 april 2024 22.37 av traianbertau