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Research Article
New Afrotropical species of Wiedemannia Zetterstedt (Diptera, Empididae, Clinocerinae)
expand article infoBradley J. Sinclair§
‡ Canadian National Collection of Insects, Ottawa, Canada
§ Canadian Food Inspection Agency, Ottawa, Canada
Open Access

Abstract

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.

Keywords

aquatic dance flies, Malawi, new species, Tanzania

Introduction

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 (Sinclair 1999a, b; Sinclair and Daugeron 2017). Some additional 18 undescribed species of Afrotropical Clinocerinae have so far been identified (Sinclair, unpubl. obs.).

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) (Sinclair 1999a, b) and appears to be most closely related to the W. zetterstedti group based on several long, erect setae on the fore coxae and acrostichal setae greatly reduced, only a few present anterior to second dorsocentral setae (Sinclair 1999a, b; Ivković et al. 2019, 2022). The Afrotropical species of Wiedemannia are divided into three species-groups: W. rudebecki-group from southern Africa (W. edendalensis Smith, W. hughesi Smith, W. gorongoza Smith, W. rudebecki Smith), the W. reducta-group from Uganda (W. reducta Garrett Jones, W. submarina Garret Jones) and the W. aquatica-group from Kenya (W. aquatica (Becker), W. kenyae Sinclair) (Sinclair 2003). In addition to the above eight species, two new species from Malawi and Tanzania (Sinclair and Daugeron 2017) are described in the present study.

Materials and methods

This study is based on material loaned from the following institutions:

NMSA KwaZulu-Natal Museum, Pietermaritzburg, South Africa;

ZMUC Natural History Museum of Denmark, Zoological Museum, Copenhagen, Denmark.

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 Cumming and Wood (2017). Photographs of pinned specimens were taken with a Leica camera model DFC5400 using Leica Application Suite X. SimpleMappr (Shorthouse 2010) was used to plot the distribution of each species.

Taxonomy

Wiedemannia kilimanjaro sp. nov.

Recognition

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.

Etymology

This species is a noun in apposition, named after the type locality.

Description

Male. Holotype mostly dark brown (see Remarks) (Fig. 4). Head: ocellar setae lost; several pairs of short posterior setulae; 3–5 upper postocular setae strong, spine-like, not overlapping eye; lower postocular setae slender, longer. Genal width one-fourth height of eye. Antenna brown; scape slightly longer than pedicel; postpedicel pointed ovate; arista-like stylus short, tip blunt, about twice as long as postpedicel.

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 1, 2): hypandrium longer than length of epandrium, with numerous long, slender setae extending onto lateral face; membrane at base of hypandrium with sclerotized strips. Epandrium subtriangular, densely covered with dark, long setae; surstylus with snout-like apex and long lateral setae. Subepandrial sclerite with pointed apex, projecting free between bases of clasping cercus. Clasping cercus L-shaped in lateral view; apex rounded; inner face without peg-like setae; subequal in length to height of epandrium; inner base expanded medially into one elongate lateral, tapered lobe and medially into forked process with stout setae on rounded lobe. Cercal plate with 4 long setae confined to upper sclerite. Phallus slightly arched; apex of shaft with pair of membranous sacs on either side; distiphallus sinuous, tapered, without swelling in middle.

Female. Unknown.

Distribution

This species is known only from Mt. Kilimanjaro, Tanzania (Fig. 8).

Type material

Holotype ♂, labelled (Fig. 5): “Tanzania, Kilimandjaro/ Shira Plateau [-3.054°, 37.275°], 4000 m./ 27.-28. Dec. 1975/ N. Møller Andersen leg.”; “HOLOTYPE/ Wiedemannia/ kilimanjaro/ Sinclair” [dissected] (ZMUC).

Remarks

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.

Wiedemannia londti sp. nov.

Recognition

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.

Etymology

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.

Description

Male. Head: face, gena and occiput with blue pruinescence (Fig. 6); vertex brown. Face with faint brownish median stripe; apex of facial cleft velvety brown with bright oval blue pruinescent patches on either side of cleft in frontal view. Ocellar triangle thinly pruinescent; ocellar setae long, slender, longer than postpronotal seta; several pairs of short posterior setulae; 4 upper postocular setae strong, spine-like, not overlapping eye; lower postocular setae slender, longer. Genal width one-third height of eye. Antenna brown; scape slightly longer than pedicel; postpedicel pointed ovate; arista-like stylus short, tip blunt, about twice as long as postpedicel.

Figures 1–3. 

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.

Figures 4–6. 

Afrotropical Wiedemannia, holotypes 4 W. kilimanjaro sp. nov., habitus, lateral view 5 W. kilimanjaro sp. nov., labels 6 W. londti sp. nov., habitus, lateral view 7 W. londti sp. nov., labels. Scale bar: 1.0 mm (4); 0.75 mm (6).

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. 3): hypandrium robust, subequal to length of epandrium. Epandrium subrectangular, produced dorsally; surstylus rounded, knob-like, with several marginal setulae. Clasping cercus arched, Y-shaped in lateral view; apical lobes, broadly rounded; inner face without peg-like setae; shorter than height of epandrium; without inner basal lobes. Subepandrial sclerite robust, blade-like, with pointed apex, projecting free beyond bases of clasping cercus. Cercal plate with 4 long setae confined to upper sclerite. Phallus straight; apex of shaft without membranous sacs, broadly rounded; apex of shaft prolonged anteroapically as slender process; distiphallus greatly reduced.

Female. Unknown.

Distribution

This species is known only from the type locality in Malawi (Fig. 8).

Figure 8. 

Distribution of Wiedemannia in the Afrotropical Region.

Type material

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] (NMSA).

Remarks

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.

Key to males of Afrotropical species of Wiedemannia

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 (Sinclair 1999b, fig. 19) W. hughesi Smith
Clasping cercus with apex shallowly divided into forked, broadly rounded paired lobes; phallus nearly straight (Fig. 3) W. londti sp. nov.
4 Clasping cercus deeply U-shaped (Sinclair 1999b, fig. 21) 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 (Sinclair 1999b, fig. 18) 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 (Smith 1969, fig. 378) W. gorongoza Smith
Clasping cercus with weakly developed and broadly rounded anterior lobe; posterior lobe of clasping cercus expanded dorsally (Sinclair 1999a, fig. 5) W. submarina Garrett Jones
8 Clasping cercus without distinct inner basal lobes; surstylus short and rounded (Sinclair 1999a, fig. 4) 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 (Sinclair 1999a, figs 2, 3) W. aquatica (Becker)
Clasping cercus with single inner basal lobe, divided apically; surstylus with attenuated and hooked apex (Figs 1, 2) W. kilimanjaro sp. nov.

Discussion

There are now 10 described species of Wiedemannia in the Afrotropical Region. The species are rather disjunct in Africa (Fig. 8) and are mostly confined to > 2000 m in the Afromontane region of the tropics, but reaching near sea-level in more temperate latitudes of southern Africa (Sinclair 1999a, b). The genus occurs in cooler water environments with rocky substrates. The geographical distribution and evolution of the group in Africa was discussed by Sinclair (1999a). Most collections for Clinocerinae have focused on South Africa. Greater collecting efforts throughout Africa are likely to produce additional records and species.

Acknowledgements

I am indebted to the following curators and their respective institutions for the loan of specimens: D.A. Barraclough (NMSA); T. Pape (ZMUC). Jessica Hsiung (Ottawa) competently inked the genitalia illustrations. Marija Ivković (Croatia) kindly commented on the manuscript.

References

  • Cumming JM, Wood DM (2017) [Chapter] 3. Adult morphology and terminology. In: Kirk-Spriggs AH, Sinclair BJ (Eds) Manual of Afrotropical Diptera. Volume 1. Introductory chapters and keys to Diptera families. Suricata 4, South African National Biodiversity Institute, Pretoria, 89–133.
  • Ivković M, Wahlberg E, Prevšić A (2019) Molecular phylogenetics and biogeography provide insights into the subgeneric classification of Wiedemannia Zetterstedt (Diptera: Empididae: Clinocerinae). Systematic Entomology 44(3): 559–570. https://doi.org/10.1111/syen.12340
  • Ivković M, Sinclair BJ, Wahlberg E (2022) The century old taxonomic confusion surrounding Wiedemannia zetterstedti and related species is resolved (Diptera: Empididae): revision of the W. zetterstedti group. Insects 13(5): e460. [22 pp.] https://doi.org/10.3390/insects13050460
  • Shorthouse DP (2010) SimpleMappr, an online tool to produce publication-quality point maps. http://www.simplemappr.net [Accessed June 13, 2022]
  • Sinclair BJ (1999a) Afromontane species of Wiedemannia Zetterstedt from east Africa (Diptera: Empididae). Annals of the Natal Museum 40: 93–101.
  • Sinclair BJ (1999b) Review of the Clinocerinae of southern Africa (Diptera: Empididae). Annals of the Natal Museum 40: 103–125.
  • Sinclair BJ (2003) Southern African Empidoidea (Diptera): Phylogenetic patterns and biogeographic implications. Cimbebasia 19: 205–213.
  • Sinclair BJ, Daugeron C (2017) 51. Empididae (empidid dance flies or balloon flies). In: Kirk-Spriggs AH, Sinclair BJ (Eds) Manual of Afrotropical Diptera. Volume 2. Nematocerous Diptera and lower Brachycera. Suricata 5. Pretoria: South African National Biodiversity Institute, 1221–1235.
  • Smith KGV (1969) The Empididae of southern Africa (Diptera). Annals of the Natal Museum 19: 1–342.
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