Research Article |
Corresponding author: Bradley J. Sinclair ( bradley.sinclair@inspection.gc.ca ) Academic editor: Kirstin Williams
© 2023 Bradley J. Sinclair.
This is an open access article distributed under the terms of the CC0 Public Domain Dedication.
Citation:
Sinclair BJ (2023) New Afrotropical species of Wiedemannia Zetterstedt (Diptera, Empididae, Clinocerinae). In: Dikow T, Williams K, Midgley J (Eds) Festschrift for Jason Gilbert Hayden Londt. African Invertebrates 64(2): 139-147. https://doi.org/10.3897/afrinvertebr.64.91446
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Two new species of Afrotropical Wiedemannia Zetterstedt are described: W. kilimanjaro sp. nov. (Tanzania), W. londti sp. nov. (Malawi). Both species are illustrated and an updated key to Afrotropical species of Wiedemannia is provided. The distributions of all Afrotropical species of Wiedemannia are mapped and the disjunct distribution briefly discussed.
aquatic dance flies, Malawi, new species, Tanzania
Aquatic dance flies of the subfamily Clinocerinae (Diptera: Empididae) are associated with streams, rivers and boggy areas and found worldwide, except Antarctica. Species are found from lowlands to high altitudes, usually associated with less human-impacted habitats. In the Afrotropical Region, there are 30 described species and six genera of Clinocerinae (
The genus Wiedemannia Zetterstedt are among the larger-sized flies of Clinocerinae and often occur in broader streams and rivers. The Afrotropical species of Wiedemannia form a monophyletic group, supported by characters of the male terminalia (i.e., prolongation of subepandrial sclerite and base of distiphallus with paired spicule-clothed membranous sacs and attached at antero-apical margin of phallic shaft) (
This study is based on material loaned from the following institutions:
Label data for primary types are cited from the top downward, with the data from each label in quotation marks. Labels are cited in full, with original spelling, punctuation, and date, and label lines are delimited by a slash (/). The repository of each type is given in parentheses. Terms used for adult structures primarily follow those of
This species is distinguished by its fully developed wings, numerous slender setae scattered over the hypandrium and three inner lobes of the elongate clasping cercus.
This species is a noun in apposition, named after the type locality.
Male. Holotype mostly dark brown (see Remarks) (Fig.
Thorax : antepronotum with strong, long lateral seta, nearly as long as postpronotal seta. Proepisternum with several long, brown setae. Mesonotum with 5 rather weak dorsocentral setae, with several short setulae intermixed; several short acrostichal setulae, anterior to second dorsocentral seta; 1 postpronotal seta, with several short, dark setulae; 2 notopleural setae, lower seta weaker, shorter than upper; 1 presutural supra-alar seta; 1 postsutural supra-alar seta, with several setulae; 1 postalar seta; 1 pair short scutellar setae, similar to dorsocentral setae, with dark marginal and discal setulae. Laterotergite with cluster of brown setae.
Wing : length 4.6 mm; membrane infuscate, veins darker; basal costa seta not extending to humeral crossvein. Origin of veins M1 and M2 widely separated at end of cell dm, subequal to length of crossvein r-m. Vein CuA+CuP absent. Pterostigma not visible. Costal margin with short, strong erect setae beyond apex of Sc. Halter with dark knob.
Legs : uniformly covered with rows of small dark setulae, slightly longer on ventral side of fore femur; fore femur without strong preapical setae; fore coxa with 2 long erect setae; hind tibia with 4–5 erect, spine-like posterodorsal setae.
Abdomen : concolourous with thorax, covered in short setae. Tergite 8 narrow, band-like.
Terminalia (Figs
Female. Unknown.
This species is known only from Mt. Kilimanjaro, Tanzania (Fig.
Holotype
♂, labelled (Fig.
Wiedemannia kilimanjaro is most closely related to W. kenyae on the basis of the elongate, narrow clasping cercus and numerous slender setae on the hypandrium and assigned to the W. aquatica group.
The holotype is dark brown, which is unusual for specimens of Wiedemannia, which usually have distinct bluish pruinescence. Some bluish pruinescence is visible at certain angles, but the brownish colouration could have resulted during the preservation process. Additional specimens of this species will certainly assist in resolving its true colouration.
This species is distinguished by its fully developed wings, fore coxae without erect, outstanding setae, clasping cercus with narrow base and Y-shaped apex, blade-like subepandrial sclerite and oddly shaped phallus, with reduced distiphallus.
It is my pleasure to name this species in honour of Jason Londt. Jason was very welcoming to me as a young visitor to the Natal Museum in 1994 and I always look forward to meeting up with him at meetings of the International Congress of Dipterology.
Male. Head: face, gena and occiput with blue pruinescence (Fig.
Male terminalia of Afrotropical Wiedemannia 1 W. kilimanjaro sp. nov.. lateral view 2 W. kilimanjaro sp. nov., clasping cercus, anterior view 3 W. londti sp. nov., lateral view. Scale bars: 0.1 mm. Abbreviations: cerc pl – cercal plate; cl cerc – clasping cercus; epand – epandrium; hypd – hypandrium; ph – phallus; sbepand scl – subepandrial sclerite; sur – surstylus.
Thorax : pleura and postpronotal lobe with blue pruinescence; scutum brown with faint pair of black vittae. Antepronotum with strong, long lateral seta, nearly as long as postpronotal seta. Proepisternum with several long, pale setae. Mesonotum with 5 long dorsocentral setae, with several short setulae intermixed; several short acrostichal setulae, anterior to second dorsocentral seta; 1 postpronotal seta, with several short, dark setulae; 2 notopleural setae, lower seta weaker, shorter than upper, with numerous black setulae; 1 presutural supra-alar seta, with numerous black setulae; 1 postsutural supra-alar seta, with several setulae; 1 postalar seta; 1 pair scutellar setae, longer than dorsocentral setae, with dark marginal and discal setae and setulae. Laterotergite with cluster of pale setae.
Wing : length 4.1 mm; membrane infuscate, veins darker; basal costa seta not extending to humeral crossvein. Origin of veins M1 and M2 widely separated at end of cell dm, subequal to length of crossvein r-m. Vein CuA+CuP absent. Pterostigma not visible. Costal margin with short, strong erect setae beyond apex of Sc. Halter with dark knob; base of shaft pale brown.
Legs : coxae with blue pruinescence, concolourous with pleura; remaining leg segments dark brown. Fore femur with posteroventral row of fine setae, shorter than width of femur; fore tibia with erect ventral setae, shorter than width of tibia; otherwise uniformly covered with rows of small dark setulae; fore femur without strong preapical setae; fore coxa without erect setae; hind tibia with 2–3 pairs of strong ventral setae.
Abdomen : blue pruinescent, concolourous with thorax, covered in short setae. Tergite 8 narrow, band-like.
Terminalia (Fig.
Female. Unknown.
Holotype
♂, labelled (Fig. 7): “MALAWI Mulanje Mnt./ Likabula river valley [-15.938°, 35.519°]/ 28–30.xi.1980 1535Dc/ 1000m Stuckenberg &/ Londt Riverine/ Brachystegia woodland”; “HOLOTYPE/ Wiedemannia/ londti/ Sinclair” [dissected] (
This is the first species of Empididae to be described from Malawi. Wiedemannia londti is most similar to the odd South African species, W. hughesi with absence of erect setae on the fore coxae, enlarged hypandrium and reduction of the distiphallus.
1 | Wings greatly reduced and strap-like | W. reducta Garrett Jones |
– | Wings normally developed | 2 |
2 | Fore coxae without 2–3 erect setae; apical filament of phallus or distiphallus greatly reduced; apex of phallic shaft broader than base, without membranous sacs | 3 |
– | Fore coxae with 2–3 erect setae; apical filament of phallus or distiphallus long and slender; apex of phallic shaft at most slightly broader than base, with membranous sacs | 4 |
3 | Clasping cercus deeply divided into separate lobes; phallus strongly bent near mid-length ( |
W. hughesi Smith |
– | Clasping cercus with apex shallowly divided into forked, broadly rounded paired lobes; phallus nearly straight (Fig. |
W. londti sp. nov. |
4 | Clasping cercus deeply U-shaped ( |
W. rudebecki Smith |
– | Clasping cercus not deeply U-shaped | 5 |
5 | Clasping cercus mitten-shaped in lateral view | 6 |
– | Clasping cercus slender with expanded base in lateral view | 8 |
6 | Apex of phallic shaft somewhat expanded ( |
W. edendalensis Smith |
– | Apex of phallic shaft slender, not expanded | 7 |
7 | Clasping cercus with distinct, broadly rounded anterior lobe; posterior lobe of clasping cercus expanded posteriorly ( |
W. gorongoza Smith |
– | Clasping cercus with weakly developed and broadly rounded anterior lobe; posterior lobe of clasping cercus expanded dorsally ( |
W. submarina Garrett Jones |
8 | Clasping cercus without distinct inner basal lobes; surstylus short and rounded ( |
W. kenyae Sinclair |
– | Clasping cercus with distinct inner basal lobes; surstylus truncate or with attenuated apex | 9 |
9 | Clasping cercus with pair of separate inner basal lobes; surstylus truncate and broad ( |
W. aquatica (Becker) |
– | Clasping cercus with single inner basal lobe, divided apically; surstylus with attenuated and hooked apex (Figs |
W. kilimanjaro sp. nov. |
There are now 10 described species of Wiedemannia in the Afrotropical Region. The species are rather disjunct in Africa (Fig.
I am indebted to the following curators and their respective institutions for the loan of specimens: D.A. Barraclough (