Research Article |
Corresponding author: Axel Ssymank ( ssymanka@bfn.de ) Academic editor: Burgert Muller
© 2021 Axel Ssymank, Kurt Jordaens.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Ssymank A, Jordaens K (2021) Description of the female of Syrittosyrphus opacea Hull, 1944 (Diptera, Syrphidae, Eristalinae) with additional notes on the genus. African Invertebrates 62(1): 339-353. https://doi.org/10.3897/AfrInvertebr.62.61504
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The taxonomy of Syrphidae is far from being complete in the Afrotropical Region and many species have been described from a single sex only. One of these is the enigmatic monotypic genus Syrittosyrphus Hull, 1944, of which, so far, only the male of Syrittosyrphus opacea Hull, 1944 was described from the Eastern Cape Province in South Africa. Here, we re-describe the male and describe the female. We summarise all known distribution records from South Africa (Eastern Cape, KwaZulu-Natal and Limpopo Provinces) and Zimbabwe (Vumba), of which several are new. We also provide notes on the species’ ecology.
Afrotropical Region, flower fly, hoverfly, identification
The Afrotropical Region is relatively poor in genera and species of hoverflies or flower flies (Diptera: Syrphidae) (
Recently, a complete key to the genera of the Afrotropical Region was compiled (
Study material was obtained from the following museums and personal collections:
content-type="institution" ASPC Axel Ssymank, personal collection, Wachtberg, Germany;
WBPC Werner Barkemeyer, personal collection, Flensburg, Germany.
Morphological terminology followed
Syrittosyrphus Hull, 1944: 203. Type species: Syrittosyrphus opacea Hull, 1944, (by monotypy).
Syrittosyrphus opacea
Hull-
The genus differs from any other genus of hoverflies in the following combination of characters: scutellum with deep rim and fringe of pile ventrally, metasternum pilose, coxae with long pile, all sternites with long pile, wing cell r1 widely open, wing vein R4+5 deeply sinuate, stigmal cross-vein present, petiole of anal cell long.
Syrittosyrphus opacea Hull: Holotype (Fig.
South Africa • 1 ♂; Cathedral Peak Area, KwaZulu-Natal; 28°57'S, 29°12'E; 16 Dec 1977; J.G.H. Londt leg.;
(Figs
Body length: 15.0 mm (n = 1); wing length: 11.4 mm (n = 1).
Head
[Figs
Thorax
(Figs
Legs
[Figs
Wing
(Figs
Abdomen
(Figs
Genitalia
[Fig.
Female genitalia of Syrittosyrphus opacea Hull, 1944 A dorsal view B ventral view C lateral view. Abbreviations: ap, apodeme of epiproct; cerc, cercus; ep, epiproct; hyp, hypoproct; ll, lateral lobe to the epiproct; mem, membranous area between epiproct and cerci; st8, sternite 8; st9, sternite 9; tg8, tergite 8.
Figs
Body length: 14.0 mm (n = 1); wing length: 11.4 mm (n = 1)
Similar to male, except for distinct sexual dimorphism. Frons with a broad greyish pollinose band with grey setae (Fig.
We here have described, for the first time, the female of the Afrotropical hoverfly, Syrittosyrphus opacea, which allowed us to update the diagnosis of this monotypic genus. As a result, the genus now correctly keys out in a key to the genera of Syrphidae of the Afrotropical Region (
Syrittosyrphus opacea seems to be a SE African endemic and, so far, has only been recorded from South Africa (nine localities) and Zimbabwe (one locality) (Fig.
With the detailed re-description of the male and the description of the female provided here, both sexes of Syrittosyrphus opacea can now be unambiguously identified. The available records of this rare SE African endemic species suggest a distribution linked to three forest types along the Eastern Escarpment (Northern Afrotemperate Forest and Northern and Southern Mistbelt Forests). Based on these habitats, together with vegetation maps, future research may close distribution gaps and clarify the biology.
We would like to thank Kirstin Williams and John Midgley (KwaZulu-Natal Museum, Pietermaritzburg, South Africa) and Burgert Muller (now at the National Museum, Bloemfontein, South Africa) for sending us specimens on loan and for information on the distribution records and habitats. We thank Menno Reemer, Gil Felipe Gonçalves Miranda and an anonymous referee for their valuable comments which have improved the manuscript considerably. We also thank Gil Felipe Gonçalves Miranda for a fruitful discussion on the female genital morphology. Financial support was received through the Directorate-general Development Cooperation and Humanitarian Aid (DGD) to the RMCA (project DIPoDIP: Diversity of Pollinating Diptera in South African Biodiversity Hotspots) and the joint Belspo-NRF South Africa project DIPTATEACH (Diptera Museum Collections as a Source for Taxonomic Research and Teaching Activities).