Research Article |
Corresponding author: Torsten Dikow ( dikowt@si.edu ) Academic editor: Pavel Stoev
© 2016 Jason G.H. Londt, Torsten Dikow.
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:
Londt J, Dikow T (2016) A review of the genus Trichoura Londt, 1994 with the description of a new species from the Northern Cape Province of South Africa and a key to world Willistonininae (Diptera, Asilidae). African Invertebrates 57(2): 119-135. https://doi.org/10.3897/AfrInvertebr.57.10772
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The South African assassin-fly genus Trichoura Londt, 1994 is reviewed. A new species, Trichoura pardeos sp. n., is described from the arid Karoo in north-western South Africa. A new key to all seven recognized species is provided and the distribution and phenology are discussed. The world fauna of Willistonininae is reviewed, a new taxon Sisyrnodytinitribe n. (type genus Sisyrnodytes Loew, 1856) is established for Ablautus Loew, 1866, Acnephalomyia Londt, 2010, Ammodaimon Londt, 1985, Astiptomyia Londt, 2010, Sisyrnodytes, and Sporadothrix Hermann, 1908 and photographs for all Willistonininae genera are provided.
Assassin flies, robber flies, Afrotropical, Nearctic, new tribe, new species
The Afrotropical asilid genus Trichoura Londt, 1994 is of particular interest. Not only is it currently a South African endemic associated with rather arid environments, but, in an Afrotropical context, it is believed to be most closely related to a number of Afrotropical genera previously included in the Stenopogoninae (
The discovery of a new species requiring description provides an opportunity to review the genus and highlight its interesting taxonomic position.
The taxonomic history of Trichoura is short and uncomplicated and can be briefly summarised as follows:
Terminology follows mainly that proposed by
Trichoura torynopoda Londt, 1994: 93 by original designation.
Small, brown-yellow, strongly silver pruinose asilids with the following combination of characters: Head: Clearly wider than high in anterior view; mystax white, macrosetae tightly packed, confined to a slight gibbosity on lower facial margin; face narrow, frons diverging abruptly from level of antennal sockets; macrosetae on lateral margin of frons; palpi small, 2-segmented. Thorax: Anterior anepisternal setae absent; anatergites asetose; postmetacoxal area membranous. Wing: Transparent, immaculate, fairly uniformly microtrichose; alula reduced in size; C extends almost entirely around wing margin (weakly after junction of CuA and CuP), cells m3, and cua closed and stalked. Legs: Pulvilli and empodia well developed; metathoracic coxae with an anteriorly situated protuberance. Abdomen: ♂ terminalia unrotated; ♂ epandrium commonly with long, silvery, prone setae masking shape; hypandrium absent or fused with well-developed gonocoxites which are fused medially to form a cup-shaped sclerite supporting gonostyli and other elements of the terminalia.
Photographs of Trichoura: 1 male T. tankwa (USNMENT01115152), dorsal (Morphbank #860636) 2 same, lateral (#860638) 3 same, head anterior (#860640) 4 male T. torynopoda (USNMENT01295405) head anterior (#860659) 5 same, dorsal (#860655) 6 same, lateral (#860657). Scale bars: 1 mm.
Gr. Pardos m. – leopard + oros, -eos n. mountain. Named after the type locality of Tierberg Nature Reserve (Tierberg meaning tiger (= leopard) mountain).
Based on all available NMSA material.
Head: Dark red-brown to black, but colour masked by strong silver and gold pruinescence, white and pale yellow-white setose. Antennal scape and pedicel brown-orange, postpedicel and terminal style dark red-brown, fine silver pruinose, scape and pedicel yellow-white, short setose, style tipped with almost transparent spine-like sensory element. Segmental ratios (scape (as 1) : pedicel : postpedicel : style (segment + sensory element) – 1 : 1.4 : 3.8 : 1.2 (0.8 + 0.3). Face dark red-brown to black, but colour masked by strong silver pruinescence, profile plane except for slight epistomal gibbosity. Mystax shiny white, moderately well-developed, confined to small epistomal gibbosity, setae closely arranged forming a dorsoventrally compressed shield covering proboscis. Face narrow, parallel-sided, width of face: width of head (at widest point) ratio – 1 : 8.2: 2.2. Frons and vertex somewhat divergent, width of face to width of vertex (at level of anterior ocellus) ratio – 1 : 2.2, dark red-brown to black, but colour masked by strong silver (frons) and weak gold pruinescence (vertex). 1 pair of frontal setae. Ocellar tubercle projecting only slightly above vertex, with 2 pairs of small ocellar setae. Postocular (occipital) region dark red-brown to black, but colour masked by strong silver pruinescence. Occiput with short, pale yellow-white macrosetae dorsally, short white macrosetae laterally and many fine, shiny white setae ventrally. Palpi dark red-brown, small, 2-segmented, fine pale yellow setose. Proboscis straight, tubular, dark red-brown to black, weakly fine white setose.
Thorax: Dark red-brown to black, but colour masked by silver and silver-gold pruinescence, pale yellow and fine white setose. Pronotum dark red-brown, silver pruinose, white setose. Mesonotum dark red-brown to black, entirely silver to silver-gold pruinose, fine white setose except for moderately well developed, pale yellow-white lateral macrosetae (2 npl, 1 spal, 2 pal). Scutellum dark red-brown, entirely silver pruinose, asetose except for 1 pair apical macrosetae. Pleura dark red-brown to black, but entirely strongly silver pruinose, almost asetose except for c. 5 white katatergal macrosetae. Anepisternal setae absent. Anatergites uniformly strongly gold pruinose, asetose.
Legs: Coxae red-brown, strongly silver pruinose, white setose; metathoracic coxae with small bulbous protuberance on anterior surface. Femora red-brown with orange distal and proximal ends, white setose. Tibiae and tarsi orange, terminal parts red-brown, white setose. Claws black with brown-orange basal parts, shorter than terminal tarsomere, gently curved. Empodium orange, straight, slightly shorter than claws. Pulvilli pale yellow, longer than empodium. Wings (Fig.
Abdomen: Entirely dark red-brown, moderately fine gold-silver pruinose, short white setose (T1 with longer setae laterally and along entire posterior margin). ♂ tergites and sternites entirely pruinose, including epandrium which is covered with long shiny white setae. Fused gonocoxites and other visible parts of genitalia shiny apruinose. ♀ with segments 1–6 entirely pruinose, segments 7–9 shiny apruinose. ♂ terminalia (Figs
SOUTH AFRICA: ♂ holotype, ‘South Africa: N Cape / Tierberg Nature Reserve / 28°43.012'S, 020°59.805'E / 850m J Londt & T Dikow / 5.ii.2004, sparsely / vegetated exposed hillside’ (NMSA).
3♂ 3♀, same data as holotype (NMSA); 1♂ 1♀, same data (USNMENT01288302–USNMENT01288303, USNM).
Known only from the type locality. Collected in February (Table
Photographs of Trichoura pardeos sp. n. (paratype USNMENT01115152) and habitat: 10 dorsal (Morphbank #860646) 11 lateral (#860648) 12 head anterior (#860650) 13–14 rocky hill habitat at type locality at Tierberg Nature Reserve, Keimoes, Northern Cape, South Africa (28°43'01"S 020°59'48"E). Habitat photographs by T. Dikow. Scale bars: 1 mm.
Species | J | A | S | O | N | D | J | F | M | A | M | J |
---|---|---|---|---|---|---|---|---|---|---|---|---|
T. krugeri | – | – | – | – | – | ● | – | – | – | – | – | – |
T. mesochora | – | – | – | – | – | – | ● | – | ● | – | – | – |
T. pardeos | – | – | – | – | – | – | – | ● | – | – | – | – |
T. proctomeces | – | – | – | ● | – | – | – | – | – | – | – | – |
T. tankwa | – | – | ● | – | ● | ● | – | – | – | – | – | – |
T. torynopoda | – | – | – | – | – | ● | – | – | – | – | – | – |
T. tyligma | – | – | ● | – | – | – | – | – | – | – | – | – |
All previously described Trichoura species have been registered in ZooBank and are listed below with their globally unique identifier, distributional records from
Trichoura krugeri Londt, 1994
http://zoobank.org/9CD32242-681F-425A-8BE5-9B45A0AD83EF
Fig.
South Africa: Mpumalanga Province: Kruger Park, Timbetene Tswiri waterholes, near Skukuza (c. 24°59'40"S, 031°35'40"E c. 290m).
Map of South Africa with elevational relief and distribution of Trichoura species. (SimpleMappr 6129 - http://www.simplemappr.net/map/6129)
Trichoura mesochora Londt, 1994
http://zoobank.org/9C8BEFAC-5D2C-4A79-8581-7BFE0FB42342
Fig.
South Africa: Free State Province: 30 km E Boshof (c. 28°35'51"S 025°31'35"E c. 1295m); Krugersdrift Dam (c. 28°52'42"S, 025°57'13"E c. 1245m); Northern Cape Province: 35 km W Kimberley (c. 28°43'11"S, 024°24'10"E c. 1125m).
Trichoura proctomeces Londt, 1994
http://zoobank.org/D5A4DBFE-D6E5-45F4-8D97-DD58C51C5477
Fig.
South Africa: Western Cape Province: Knersvlakte north Vanrhynsdorp (c. 31°34'57"S, 18°43'40"E c. 125m); Knersvlakte (c. 31°35'15"S, 18°29'15"E c. 105m).
Trichoura tankwa Londt, 1994
http://zoobank.org/D41CAC5A-77E7-4BFE-BE54-B31D365A5664
Figs
South Africa: Northern Cape Province: Tankwa Karoo, Waterval (c. 32°21'00"S, 20°10'48"E c. 530m); 12 km S Calvinia (31°34'10"S, 19°43'56"E 1080m).
New records are available for this species that extend the distribution considerably:
5♂ 2♀, ‘Sth Africa: N Cape / 12km S of Calvinia / 31°34'10"S, 19°43'56"E / 7.ix.2002 J.G.H. Londt / 1080m Sandy roadside’ (NMSA); 3♂ 3♀ ‘South Africa: Western Cape: De Zeekoe Guest Farm, 33°37'26"S, 022°08'39"E, 294 m, 2015-12-07 collected p.m. (noon–15:00), Little Karoo veld, perching on low vegetation, Dikow, T.’ (USNMENT01115257, USNMENT01115051–USNMENT01115152, USNMENT01136084–USNMENT01136085, USNMENT01115175, USNM).
Trichoura torynopoda Londt, 1994
http://zoobank.org/38285701-CAFE-43AF-AF8F-1AD9C90369BD
Figs
South Africa: North West Province: Bloemhof (c. 27°39'S 25°36'E c. 1235m); Gauteng Province: Pretoria, Waterkloof (c. 25°46'45"S 028°14'41"E c. 1440m).
New records from the same collecting event on which the species was based are available.
4♂, ‘Pretoria / Waterkloof / xii.15 / H.K. Munro’ (USNMENT01295405–USNMENT01295408, USNM).
Trichoura tyligma Londt, 1994 (Fig.
http://zoobank.org/8B8DD175-D35D-428C-9D76-144F9BF5DA08
South Africa: Northern Cape Province: 1 km N Kuboes (28°26'32"S, 16°59'32"E 210m).
1 | Dorsocentral macrosetae extend anteriorly to transverse suture (Fig. |
2 |
– | Dorsocentral macrosetae limited to area posterior to transverse suture (Fig. |
4 |
2 | ♂ proctiger short, bulbous and truncate in lateral view; ♀ unknown | T. tyligma |
– | ♂ proctiger elongate, evenly tapering in lateral view | 3 |
3 | ♂ proctiger shorter than epandrial lobes and projecting posteriorly; ♀ known | T. tankwa |
– | ♂ proctiger longer than epandrial lobes and ventrally directed; ♀ unknown | T. proctomeces |
4 | ♂ antenna unicolorous; metathoracic tarsomeres 2 and 3 each with a pair of dark red-brown leaf-like setae (Fig. |
T. torynopoda |
– | ♂ antennal scape and pedicel paler in colour than postpedicel; metathoracic tarsomeres of more usual development (e.g., Fig. |
5 |
5 | Fused gonocoxites of ♂ bilobed distally (best seen in ventral view) | 6 |
– | Fused gonocoxites of ♂ with a single broadly rounded mediodistal lobe | T. pardeos sp. n. |
6 | Epandrial lobes of ♂ elongate, pointed in lateral view, projecting beyond all other elements of terminalia | T. krugeri |
– | Epandrial lobes of ♂ short, broadly rounded in lateral view, not projecting beyond proctiger and gonostyli | T. mesochora |
Willistonininae can be delimited by these synapomorphies: only lower facial margin of face slightly developed, prosternum and proepisternum separated and prosternum triangular and pointed dorsally, discal scutellar setae absent, setae on legs dorsoventrally flattened (also regular, circular setae present).
The phylogenetic classification proposed by
Since the remaining genera included by
Willistonininae has its generic diversity in southern Africa with six genera occurring in and four endemic to the area. The western Nearctic has only two genera but a relatively high species diversity as Ablautus currently has 13 known species and a revision of the genus is underway with the description of some 11 new species (Herbert and Dikow in prep.).
The following key, modified from
1 | Pulvilli well-developed (Fig. |
2 |
– | Pulvilli minute or absent (Fig. |
3 |
2 | Wing with cell m3 closed and stalked (Fig. |
Trichoura |
– | Cell m3 open at margin, even if only narrowly (Fig. |
Willistonina |
3 | Vein C extends strongly around entire wing margin including cup and alula; Nearctic | Ablautus |
– | Vein C does not extend around entire wing margin | 4 |
4 | Abdomen cylindrical, not obviously dorsoventrally flattened (width : length ratio of tg2 < 1.5, Fig. |
5 |
– | Abdomen broad and obviously dorsoventrally flattened (width : length ratio of tg2 > 2, Fig. |
6 |
5 | Small flies (wing length < 3.5 mm, Figs |
Ammodaimon |
– | Larger flies (wing length > 6.0 mm, Figs |
Sporadothrix |
6 | Vein C terminating before reaching CuA+CuP (Fig. |
Sisyrnodytes |
– | Vein C terminating at point where CuA+CuP reaches wing margin (Fig. |
7 |
7 | Cell m3 open (Fig. |
Acnephalomyia |
– | Cell m3 closed and stalked; supernumerary crossvein (R3) absent on R4; pulvilli minute, difficult to detect (Fig. |
Astiptomyia |
Photographs of Willistonininae: 21 male Ablautus sp. (AAM-004314), dorsal (Morphbank #860664) 22 same, lateral (#860666) 23 male Acnephalomyia sp. (USNMENT01115145), dorsal (#860685) 24 same, lateral (#860687) 25 female Ammodaimon sp. (USNMENT00995300), dorsal (#860693) 26 same, lateral (#860695). Scale bars: 5 mm.
Photographs of Willistonininae: 27 female Astiptomyia bikos Londt, 2010 (NMSA-DIP-66454), dorsal (Morphbank #860701) 28 same, lateral (#860704) 29 female Sisyrnodytes subater Oldroyd, 1957 (USNMENT00870084), dorsal (#860710) 30 same, lateral (#860712). Scale bars: 5 mm.
Photographs of Willistonininae: 31 male Sporadothrix gracilis Hermann, 1907 (USNMENT00870183), dorsal (Morphbank #860718) 32 same, lateral (#860720) 33 male Willistonina bilineata (Williston, 1883) (UCRCENT80299), dorsal (#860726) 34 same, lateral (#860728). Scale bars: 5 mm.
The phenology of species is summarised in Table
The distribution of Trichoura species is shown in Fig.
The senior author wishes to thank the University of KwaZulu-Natal and the National Research Foundation (NRF) of South Africa for allocating funding in support of his research. The KwaZulu-Natal Museum provided various services while his wife, Ann, continued to provide assistance and support. The junior author acknowledges field work support by the Global Genome Initiative (GGI) at the Smithsonian Institution to visit the Nama and Klein Karoo in December 2015. The team at the De Zeekoe Guest Farm and in particular Dolf Grobler and J.D. Glinister are thanked for allowing collecting and accompanying the junior author in the field. Karie Darrow and Meg Gisonda are thanked for assistance in photographing specimens. Rodrigo Vieira and Aubrey Scarbrough are thanked for comments that improved the manuscript during peer review. The assistance of the conservation authorities issuing collecting permits in the Northern Cape and Western Cape Provinces is appreciated.