I seem to always take a long time to finally post a summary of my field-work in photos. Here is a summary of a trip I undertook with #TeamDiptera members Charlotte Alberts, Allan Cabrero, and Brandon Claridge in November 2018 prior to the 9th International Congress of Diptera in Windhoek, Namibia.
This trip included two main field-sites: habitats around Rooisand Desert Lodge near the Gamsberg (rooisand.com) and the Gobabeb Research & Training Centre in the heart of the Namib Desert (gobabebtrc.org).
I would like to thank the Namibian National Commission on Research, Science and Technology (NCRST) and the Ministry of Environment and Tourism (MET) for issuing collecting and export permits. Furthermore, the staff at the Gobabeb Research & Training Centre was very helpful as always and in particular Gillian Maggs-Kölling, Leena Kapulwa, Gregory Golando, and Eugene Marais assisted in many ways.
Here are some of the habitats we visited:
1. Rooisand Desert Lodge habitat where Anasillomos juergeni Dikow, 2015 (image below) and Leptogaster aganniphe Janssens, 1957 (both Asilidae) were collected.
2. View from partly vegetated sand dune at Rooisand Desert Lodge towards towering Gamsberg in the far distance, which is with 2,347 m the 3rd highest mountain in Namibia. On this sand dune Anasillomos juergeni (photo below), Anypodetus sp., and Microstylum sp. (all Asilidae) were collected.
3. For the 3rd time, I visited this site in the Namib Desert at the eastern-most edge of the Namib sand sea on the C14 north of Solitaire (Khomas, Namibia). #TeamDiptera at work (Brandon (white shirt) and Allan on the left and Charlotte on the right). We collected the following Asilidae on the dunes and interdune valleys: Anasillomos juergeni, Anypodetus sp. (different species from Rooisand), Neolophonotus sp., Astiptomyia bikos Londt, 2010, Microstylum sp., and Rhabdogaster sp. A stiletto fly in the genus Orthactia (Therevidae) was also flying on the dunes.
4. Hope Mine wash in Namib-Naukluft National Park near Gobabeb. It was very windy at this site when we visited in the afternoon and collecting wasn't quite as good as we hoped. However, we were able to collect Trichardis picta Hermann, 1906, Microphontes sp., and Neolophonotus sp. (all Asilidae).
The single female Microphontes specimen we collected represents an undescribed species. This was a great discovery on the one hand, but on the other hand the timing could not have been worse as a few days after we visited this site the revision of the genus Microphontes including the description of four new species was published (see 10.3897/afrinvertebr.59.30684).
5. With information from our Polish colleagues Krzysztof Szpila, Marcin Piwczynski, and Andrzej Grzywacz, who were also visiting Gobabeb, we found this site some 20 km north of the research station. The dry riverbed of the Kuiseb River is much wider here and made for excellent collecting. We collected Namibimydas psamminos Dikow, 2012 (image below), an undescribed genus of Mydidae (image below), Eremohaplomydas sp., and Krzysztof Szpila also collected a species of Afroleptomydas (all Mydidae). In terms of Asilidae, we collected Prytanomyia kochi (Lindner, 1973), Neolophonotus sp., Trichardis picta, and Stichopogon hermanni Bezzi, 1910.
6. Collecting in the various habitats near the Gobabeb station itself was very productive. We collected the following species: Anasillomos juergeni, Prytanomyia kochi, Stichopogon hermanni, Stichopogon punctum Loew, 1851, Laphyctis eremia Londt & Dikow, 2018, Astiptomyia bikos, and Torasilus solus Londt, 2005 (all Asilidae), an undescribed genus of Mydidae, Syllegomydas sp., and Eremohaplomydas sp. (all Mydidae), and a few Therevidae species. Krzysztof Szpila also collected a species of Rhipidocephala (Asilidae), which represents a new record for Gobabeb.
The most amazing specimen was collected by Charlotte – she collected a female of one of the largest Afrotropical Mydidae species in the genus Syllegomydas in the dry Kuiseb River bed, which represents the 6th specimen of this yet undescribed species. The Eremohaplomydas specimens also represent an undescribed species new to science. The Torasilus solus specimens are, so far, the only assassin flies known to fly on the high dunes (middle photo above).
7. On our drive back to Windhoek, we stopped at this roadside near the Gamsberg Pass in the Khomas Hochland (highland) with typical Acacia savannah. We collected Sisyrnodytes sp., Stichopogon punctum, Stichopogon caffer Hermann, 1907, Afroholopgon sp., and Rhabdogaster sp. (all Asilidae). To collect five species of assassin flies in this dry habitat was somewhat of a surprise, but shows how these flies are adapted to live in arid environments.
Here are some of the photographs of flies in nature taken with an Olympus OM-D EM-5 Mark II and a f/2.8 60 mm macro-lens (= 120 mm focal length in 35 mm photography):
8. Anasillomos juergeni Dikow, 2015 (Asilidae) at Rooisand Desert Lodge. See iNaturalist observation: 64122992.
9. Stichopogon hermanni Bezzi, 1910 (Asilidae) on small sand dunes at Gobabeb Research & Training Centre. See iNaturalist observation: 64174876.
10. Trichardis picta Hermann, 1906 (Asilidae) mating (female on the right) in dry Kuiseb River bed at Gobabeb. See iNaturalist observation: 64175823.
11. Namibimydas psamminos Dikow, 2012 (Mydidae) at Kuiseb River bed 20 km north Gobabeb. See iNaturalist observation: 64176614.
12. Undescribed genus and species of Mydidae (Syllegomydinae) at Gobabeb.
13. Namibiotes argentata Barraclough, 2000 (Ulidiidae) on !nara (Acanthosicyos horridus, Curcubitaceae). This fly is so far only known to live on the !nara plant which is endemic to the Namib Sand sea within the Namib Desert. See iNaturalist observation: 64177007.
Other impressions of Namibia:
14. Male Welwitschia mirabilis (Welwitschiaceae) – enigmatic plant of the Namib Desert – at Hope Mine wash.
15. A sight I have never seen on my four visits to the Namib – the desert can be green.
16. Springbok (Antidorcas marsupialis Sundevall, 1847, Bovidae) grazing the Namib gravel plains.
17. Lesser flamingoes (Phoenicoparrus minor Geoffroy Saint-Hilaire, 1798, Phoenicopteridae) near Walvis Bay.
18. A praying mantis (Chroicopteridae, ID via iNaturalist) at Hope Mine wash. See iNaturalist observation: 64175314.
19. Fruit of Phaeoptilum spinosum (Nyctaginaceae) at roadside near Gamsberg Pass. See iNaturalist observation: 64177671.
TeamDiptera:
20. #TeamDiptera (Allan Cabrero, Charlotte Alberts, Brandon Claridge, Torsten Dikow from right to left) in front of huge !nara plant.
21. #TeamDiptera equipment.
Posted by Torsten Dikow.
Update 2021-04-13: Identifications or links to observations at iNaturalist were added.