Mesembrius strigilatus (Bezzi, 1912)

Jordaens, Kurt, Goergen, Georg, Skevington, Jeffrey H., Kelso, Scott & Meyer, Marc De, 2021, Revision of the Afrotropical species of the hover fly genus Mesembrius Rondani (Diptera, Syrphidae) using morphological and molecular data, ZooKeys 1046, pp. 1-141 : 1

Mesembrius strigilatus (Bezzi, 1912) Figs 22 , 42 , 65 , 102 , 123 , 146 , 172 , 197 , 203 , 224

Tubifera (Mesembrius) strigilata Bezzi, 1912: 436.

Helophilus (Mesembrius) strigilatus - Bezzi (1915): 96 - Curran and Bryan (1926): 82.

Mesembrius strigilatus - Hervé-Bazin (1914a): 481 - Curran (1927): 62 - Curran (1939): 10 - Szilády (1942): 92 - Smith and Vockeroth (1980): 504.

Differential diagnosis.

Mesembrius strigilatus males lack an apical pile brush on the profemur and have a metatibia which is strongly curved. The metafemur is curved, has a patch of conspicuous black pile at the base and, perpendicular to this, a stretch of dense black pile on the ventroposterior side. Tergite II has a pair of very large and rounded maculae and a narrow black medial marking. The male is distinguished from any other species by the strongly curved metafemur and metatibia, except from M. nigriceps though the metafemur and metatibia are less curved in the latter. It differs further from M. nigriceps in the the colour of the face (white to yellow in M. strigilatus ; black in M. nigriceps ), in the size and shape of the maculae on tergite II which are large and rounded (small and nearly triangular in M. nigriceps ) and by the narrow black medial marking on tergite II (broad in M Mesembrius nigriceps ). Females have a frons which is pale pilose on the ventral half. Females of M. strigilatus have a pair of yellow maculae on tergite II (fascia in the spined morph of M. caffer and in M. capensis ). Pro- and mesofemur are dark brown to black (yellow-brown in M. senegalensis ), the metafemur lacks a ventral medial swelling (present in M. minor ), the face is not markedly produced downwards (produced downwards in M. vockerothi sp. nov.) and the mesofemur has long black pile ventrally, especially on the distal half (very few and short black pile on distal end in the nominal morph of M. caffer ).

Examined material.

Tubifera strigilata Bezzi: Lectotype (hereby designated), male, “LECTOTYPUS” " SYNTYPUS ♂ // Tubifera (Mesemb.) // Tubifera strigilata // Bezzi, 1912" " Congo Francese // Fernand-Vaz // IX-X.1902. L. fea" "RMCA PIC // 00033" "Museo Civico // di Genova" “LECTOTYPUS” [MSNG] . Paralectotype, 4 males, " SYNTYPUS ♂ // Tubifera (Mesemb.) // Tubifera strigilata // Bezzi, 1912" " Congo Francese" // Fernand-Vaz // IX-X.1902. L. fea" "Museo Civico // di Genova" "PARA- // LECTOTYPUS " [MSNG] . Paralectotype, female, " SYNTYPUS ♀ " " Tubifera (Mesemb.) // Tubifera strigilata // Bezzi, 1912" "Museo Civico // di Genova" "PARA- // LECTOTYPUS " [MSNG] .

Other material

Benin • 1♂ 1♀; Azaourissé ; 7 Mar 2018; K. Jordaens leg.; KMMA • 1♂; Calavi ; 27 Jan 2017; G. Goergen leg.; IITA • 1♀; Cotonou ; 14 Dec 2013; G. Goergen and K. Jordaens leg.; KMMA • 1♀; Cotonou ; Feb 2003; G. Goergen leg.; IITA • 1♀; Cotonou ; Dec 2003; G. Goergen leg.; IITA • 1♂; Lokossa ; Jun 2006; G. Goergen leg.; IITA • 1♂; Pahou ; 11 Jan 2014; G. Goergen leg.; IITA • 1♂ 1♀; Pobé ; 27 Jan 2016; G. Goergen leg.; IITA • 2♂♂; Porto Novo ; 20 Jan 2018; G. Goergen leg.; IITA • 1♂ 1♀; Gblo Gblo ; 11 Sep 2014; G. Goergen leg.; KMMA • 1♀; Pahou ; 11 Jan 2014; G. Goergen leg.; KMMA • 1♂ 1♀; Porto Novo ; 27 Jan 2016; K. Jordaens leg.; KMMA • 7♂♂; Porto Novo ; 7 Mar 2018; K. Jordaens leg.; KMMA • 1♀; Sérou ; Nov 2016; G. Goergen leg.; KMMA • 1♂ 3♀♀; Pobé ; 12 Dec 2013; G. Goergen and K. Jordaens leg.; KMMA • 4♂♂ 4♀♀; Pobé ; 28 Jan 2016; G. Goergen and K. Jordaens leg.; KMMA. Burundi • 2♂♂; Bujumbura ; 21 Feb 2017; G. Goergen leg.; KMMA • 1♂; Nyanza-Lac ; 14 Oct 2013; L. Ndayikeza leg.; OBPE • 1♀; Rusizi River ; 10 Nov 2010; L. Ndayikeza leg.; OBPE. Cameroon • 1♂; Batanga; collection date unknown; A. I. Good leg.; CNC • 5♂♂ 2♀♀; Douala ; 9 Jul 1974; J.A.W. Lucas leg.; RMNH. Democratic Republic of the Congo • 2♀♀; Haut-Katanga ; 4 Sep 1930; G.F. de Witte leg.; KMMA • 1♀; Equateur , Bamania; 21 Jul 1924; J. Bequaert leg.; KMMA • 1♀; Equateur , Bamania; 24 Jul 1924; J. Bequaert leg.; KMMA • 1♂; Basoko ; Oct 1948; P.L.G. Benoit leg.; KMMA • 1♂; Bokuma ; Jul 1962; R.P. Lootens leg.; KMMA • 1♀; Mai-Ndombe, Bololo, Makamendulu; 1938; H. Schouteden leg.; KMMA • 2♂♂; Boma ; Jul 1915; Lang and Chapin leg.; KMMA • 1♀; Boma ; 16 Jun 1915; Lang and Chapin leg.; KMMA • 1♀; Boma ; 17 Jun 1915; Lang and Chapin leg.; KMMA • 1♀; Boma ; 18 Jun 1915; Lang and Chapin leg.; KMMA • 4♀♀; Boma ; 4 Dec 1920; H. Schouteden leg.; KMMA • 1♀; Boma ; 11 Jul 1920; H. Schouteden leg.; KMMA • 1♂ 1♀; Boma ; 12 Jul 1920; H. Schouteden leg.; KMMA • 1♀; Haut-Lomami, Bukama ; 8 Jun 1911; J. Bequaert leg.; KMMA • 1♀; South-Kivu, Bukavu ; May 1949; H. Bomans leg.; KMMA • 1♂; Equateur , Eala; Jul 1931; H.J. Brédo leg.; KMMA • 1♀; Equateur , Eala; Nov 1931; H.J. Brédo leg.; KMMA • 1♀; Equateur , Eala; 7 Oct 1931; H.J. Brédo leg.; KMMA • 1♂; Equateur , Eala; Jul 1932; A. Corbissier leg.; KMMA • 1♀; Equateur , Eala; Apr 1933; A. Corbissier leg.; KMMA • 1♂; Equateur , Eala; 1933; A. Corbissier leg.; KMMA • 1♀; South-Kivu , Kabare; 1♀ ; 31 Jul 1914; J. Bequaert leg.; KMMA • 1♀; Lomami, Kabinda; date unknown; Schwetz leg.; KMMA • 1♂; Kachichwe ; 17 Jan 1912; Dr. Bequaert leg.; KMMA • 1♀; Kalemie ; Dec 1918; R. Mayné; leg.; KMMA • 1♂; Lualaba; Kabombo ; 29 Jun 1947; M. Poll leg.; KMMA • 1♀; Léopoldville [= Kinshasa] ; 28 Oct 1951; mevr. Bequaert leg.; KMMA • 1♂; Tshopo, Stanleyville [= Kisangani] ; Apr 1915; Lang and Chapin leg.; KMMA • 1♂; Equateur , Lukolela; 17 Jul 1926; J. Bequaert leg.; KMMA • 2♂♂; Lomami, Luputa ; Mar 1935; Bouvier leg.; KMMA • 1♀; Natl. Parc Albert, Rwindi, St. Edouard ; 17 Apr 1936; L. Lippens leg.; KMMA • 1♀; Tumbalunga, Dibaya ; 8 Nov 1930; G.F. de Witte leg.; KMMA • 1♀; Ubani, Bosobolo ; 8-11 Jan 1932; H.J. Brédo leg.; KMMA • 1♀; Ubangi, Tungu ; 4 Mar 1932; H.J. Brédo leg.; KMMA • 1♀; Uele, Garamba ; Jul 1912; Lang and Chapin leg.; KMMA • 1♂ 1♀; Mai-Ndombe, Wimbali ; Jul 1913; P. Vanderijst leg.; KMMA • 1♀; 30 Sep 1913; P. Vanderijst leg.; KMMA. Gabon • 1♀; Lolo River ; 22 May 1925; J. Rodhain leg.; KMMA . Ghana • 1♀; Nsakjam ; 13 Sep 2016; G. Goergen leg.; KMMA • 1♂; Tema ; 19 Dec 2004; G. Goergen leg.; IITA • 1♂; Kumasi ; 6 Nov 1946; J. Bowden leg.; NMSA. Kenya • 1♂; Kabete ; 12 Jun 1916; T.J. Anderson leg.; NHMUK • 1♂; Merifano ; Nov 1932; McArthur leg.; NMK • 1♀; Mugura Forest ; 2 May 1981; R.H. Markham leg.; NMK • 1♀; Zwani ; date unknown; van Someren leg.; CNC . Madagascar • 1♂; Antananarivo ; 28 Feb 2016; G. Goergen leg.; IITA. Malawi • 4♂♂ 2♀♀; Chiromo; date unknown; J.E.S. Old. leg.; NHMUK • 1♂; Mount Mulanje ; 4 Oct 1913; S.A. Neave leg.; NHMUK • 1♂; Monkey Bay ; 12 Dec 1980; J.H.G. Londt leg.; NMSA • 3♂♂; Senga Hills ; 1 Dec 1980; B.R. Stuckenberg leg.; NMSA. Mozambique • 1♀; Lourenço-Marques [= Maputo]; date unknown; H.A. Junod leg.; NHMUK • 2♂♂; Sofala , Gorongosa National Park , Chitengo; 20-30 Apr 2004; M. Hauser leg. and H. Rung leg.; CAS • 2♂♂ 1♀; Sofala , Gorongosa National Park, Chitengo ; 16-30 Apr 2015; M. Hauser and H. Rung leg.; CAS • 6♂♂; Luabo, Lower Zambezi River ; 1 Jun 1957; B.R. Stuckenberg leg.; NMSA • 2♂♂; Luabo, Lower Zambezi River ; 1 Jun 1957; P. Usher leg.; NMSA • 1♂; Luabo, Lower Zambezi River ; 1 Aug 1957; P. Usher leg.; NMSA • 1♂; Siluwe Hills, W. of Beira ; 3 Jun 1964; D. Cookson leg.; NMSA. Nigeria • 1♂; Ibadan ; 14 Jun 1957; G.H. Caswell leg.; NHMUK • 1♂; Ibadan ; Dec 1988; G. Goergen leg.; IITA. Senegal • 1♀; Dassilamé, Sérére; 30 Nov 2016; S. Cavaillès leg.; SCPC . South Africa • 1♂; Durban ; Jul 1903; G. Burn leg.; NMSA • 1♂; KwaZulu-Natal , Durban, Blue Lagoon; 25 May 1991; J.A.W. Lucas leg.; RMNH • 1♂; KwaZulu-Natal , Durban; 14 May 1903; G.F. Leigh leg.; NMSA • 2♂♂; KwaZulu-Natal , Nseleni Nature Reserve ; 10 Jan 1994; Natal Museum Staff leg.; NMSA • 2♂♂; KwaZulu-Natal , St. Lucia Park Reserve ; 2 Feb 1988; J.H.G. Londt leg.; NMSA • 5♂♂; KwaZulu-Natal, Dukuduku Forest ; 18 Jul 1981; B.R. Stuckenberg leg.; NMSA • 1♂; KwaZulu-Natal, Dukuduku Forest , 4♂♂ W of St. Lucia; 26 Nov 1971; M.E. Irwin leg.; NMSA • 1♂; KwaZulu-Natal, Ndumu Game Reserve ; 26 Oct 1972; M.E. Irwin leg.; NMSA. Tanzania • 1♂; Kahe, Usambara Mountains ; 2 Jun 1916; T.J. Anderson leg.; NHMUK . Togo • 1♀; Kloto Forest ; Mar 2004; G. Goergen leg.; IITA • 1♂; Kloto Forest ; May 2016; G. Goergen leg.; KMMA. Uganda • 1♀; Busoga ; Mar 1906; A. Hodges leg.; CNC • 1♂; Tero Forest , S.E. Buddu ; 26-30 Sep 1911; S.A. Neave leg.; NHMUK. Zambia • 1♂ 1♀; Lusaka Province, 8.5 km NW Katondwe ; 20 Apr 2016; M. Hauser leg.; CSCA.

Re-description male

(Fig. 22 ). Body length: 11.2-12.5 mm. Wing length: 8.1-8.8 mm.

Head (Fig. 65 ). Eyes bare; slightly dichoptic, distance between eyes approx. the width of ocellus. Face white with dark medial vitta; white pilose; white pollinose. Distance between lateral ocellus and eye margin 1/2 width of ocellus. Occiput yellow; yellow pilose; yellow and white pollinose. Frontal triangle black; black pilose; ventral half weakly white pollinose. Frontal prominence shiny black. Antenna black; antennal arista brown.

Thorax. Scutum black with dorsally a pair of weak yellow vittae which fade out posteriorly; with very faint lateral yellow vitta; yellow-rufous pilose. Scutellum uniformly yellow-brown; yellow-rufous pilose, with some short black pile interspersed, especially in the posterior half.

Legs. Femora and entire metaleg dark brown to black; pro- and mesofemora and tarsi yellow-brown; tarsi without a small darkened medial patch. Proleg: Femur without apical pile brush; yellow pilose ventrally; with long black pile on anterodorsally; with shorter, black pile dorsally. Mesoleg: Femur similar as profemur, but with long, black pile posteriorly and posteroventrally; with black pile anterodorsally which is markedly longer in the proximal half. Metaleg (Fig. 197 ): Femur with long, yellow pile anteriorly and anteroventrally; with long black pile on the posteroventral distal 1/3; thickened on distal 1/3; no swelling on the mid-section of the ventral side. Tibia strongly curved, especially from posterior view, flattened; with very long black pile dorsally and ventrally.

Wing (Fig. 146 ). Entire wing uniformly dense microtrichose.

Abdomen (Fig. 102 ). Tergite II with a pair of very large yellow, rounded maculae; anterior black marking larger in size than posterior black marking, which mostly reach to the lateral tergite sides; medial black marking more or less parallel-sided; long yellow pilose; posterior black marking with short, stiff black pile which extend to the lateral sides. Tergite III with small, triangular to rounded black marking; long yellow pilose with some short thick black pile in medial posterior area; black marking usually strongly white pollinose. Tergite IV entirely dark brown to black, except for anterior 1/5 which is strongly white pollinose; long yellow pilose, the pile is strongly appressed on the lateral sides. Tergite V dark brown.

Genitalia (Fig. 224 ). Epandrium: Dorsal lobe of surstylus strongly bent, sickle-shaped, short yellow pilose on distal half; with long, thick black setulae at bend ventrally; distal half dorsally convex; densely covered with long yellow pile and with some equally long, but thicker black pile interspersed. Ventral lobe of surstylus bare.

Re-description female

(Fig. 42 ). Body length: 11.3-15.0 mm. Wing length: 8.1-9.4 mm.

Head. Eyes bare; dichoptic. Face white with dark medial vitta; white pilose, white pollinose. Frons black on dorsal 2/5, yellow-white on ventral 3/5; black and white pilose on ocellar triangle and just ventrally of ocellar triangle, otherwise white pilose; strongly white pollinose on ventral 3/5, weak white pollinose on dorsal 2/5. Distance between lateral ocellus and eye margin slightly less than width of ocellus. Occiput yellow-white; yellow-white pilose; yellow-white pollinose. Frontal prominence shiny black. Antenna dark brown to black; antennal arista reddish-brown.

Thorax. Scutum dark brown with a pair of dorsolateral yellow pollinose vittae which are connected posteriorly; with lateral, yellow pollinose vitta; sometimes with a fine medial white to yellow pollinose vitta; yellow pilose. Scutellum yellow-orange; yellow pilose.

Legs. Proleg (Fig. 172 ): Femur black, distal end orange-brown; yellow pilose, with short black pile interspersed. Tibia orange, darkened in distal 1/2; yellow pilose on dorsal proximal half, yellow and black pilose otherwise. Tarsi uniformly dark brown; black pilose dorsally, yellow pilose ventrally; especially the posterior side has very conspicuous thick black pile. Mesoleg: Femur black, distal end orange-brown; black and white pilose. Tibia orange-brown; orange-yellow pilose on dorsal side, black pilose on ventral side. Tarsi orange-brown with darkened dorsal medial area; black pilose. Metaleg: Femur black, distal end orange-brown; orange-yellow pilose, with short, black pile on dorsal distal end, with shorter and thicker black pile on ventral distal half; without ventral swelling in middle (Fig. 203 ). Tibia orange-brown; orange-yellow pilose with some black pile interspersed at distal end. Tarsi black dorsally, orange ventrally; black pilose dorsally; densely orange pilose ventrally.

Wing. Entire wing uniformly microtrichose.

Abdomen (Fig. 123 ). Tergite II with a pair of very large, rounded yellow-orange maculae; black pilose on triangular posteromedial section, yellow pilose otherwise; posterior black marking extends to lateral tergite sides; medial part of black marking narrow, approx. 1/10 of tergal width; posterior black marking white pollinose. Tergite III with yellow-orange fascia which occupies entire tergal length on lateral sides and approx. 1/3 of tergal length in medial section; with triangular posterior black marking that extends to the lateral tergite sides; black pilose on triangular posteromedial section, yellow pilose otherwise; posterior black marking white pollinose. Tergite IV as tergite III, but with much narrower yellow-orange fascia (approx. 1/10 of tergal length in medial section). Tergite V with narrow anterior black board; with a pair of yellow-orange maculae in anterolateral corners, otherwise black; yellow pilose; black marking strongly white pollinose, especially in anterior half.

Distribution.

Benin, Burundi, Cameroon, Democratic Republic of the Congo, Gabon, Ghana, Guinea-Bissau, Kenya, Madagascar, Malawi, Mozambique, Nigeria, Senegal, South Africa, Tanzania, Togo, Uganda and Zambia.

Comments.

See M. nigriceps .

Figures

Figures 21, 22. 21 Mesembrius spp., habitus, lateral view. M. simplicipes Curran (♂) 22 M. strigilatus (Bezzi) (♂).

Figures 41, 42. Mesembrius spp., habitus, lateral view 41 M. simplicipes Curran (♀) 42 M. strigilatus (Bezzi) (♀).

Figures 64 - 69. Mesembrius spp., head, frontal view 64 M. simplicipes Curran (♂) 65 M. strigilatus (Bezzi) (♂) 66 M. sulcus sp. nov. (♂) 67 M. tarsatus (Bigot) (♂) 68 M. tibialis sp. nov. (♂) 69 M. vockerothi sp. nov. (♂).

Figures 101 - 106. Mesembrius spp., abdomen, dorsal view 101 M. simplicipes Curran (♂) 102 M. strigilatus (Bezzi) (♂) 103 M. sulcus sp. nov. (♂) 104 M. tarsatus (Bigot) (♂) 105 M. tibialis sp. nov. (♂) 106 M. vockerothi sp. nov. (♂).

Figures 119 - 123. Mesembrius spp., abdomen, dorsal view 119 M. regulus (Hull) (♀) 120 M. rex Curran (♀) 121 M. senegalensis (Macquart) (♀) 122 M. simplicipes Curran (♀) 123 M. strigilatus (Bezzi) (♀).

Figures 143 - 146. Mesembrius spp., right wing 143 M. rex Curran (♂) 144 M. senegalensis (Macquart) (♂) 145 M. simplicipes Curran (♂) 146 M. strigilatus (Bezzi) (♂).

Figures 172 - 176. Mesembrius spp., proleg, dorsal view 172 M. strigilatus (Bezzi) (♀) 173 M. minor (Bezzi) (♀) 174 M. senegalensis (Macquart) (♀) 175 M. caffer (Loew) (♀). Mesoleg, posterior view 176 M. sulcus sp. nov. (♂). Abbreviations: bt-basitarsus, fem-femur, tib-tibia.

Figures 197 - 200. Mesembrius spp., metaleg, ventral view 197 M. strigilatus (Bezzi) (♂). Metaleg, ventral view 198 M. minor (Bezzi) (♂). Metaleg, frontal view 199 M. copelandi sp. nov. (♂). Metaleg, posterior view 200 M. senegalensis (Macquart) (♀). Abbreviations: bt-basitarsus, fem-femur, tib-tibia.

Figures 201 - 204. Mesembrius spp., metaleg, anterior view 201 M. chapini Curran (♀). Metaleg, posterior view 202 M. regulus (Hull) (♀) 203 M. strigilatus (Bezzi) (♀). Metaleg, anterior view 204 M. minor (Bezzi) (♀). Abbreviations: fem-femur.

Figures 217 - 228. Mesembrius spp., male genitalia, lateral view 217 M. nigriceps Curran 218 M. perforatus (Speiser) 219 M. platytarsis Curran syn. nov. 220 M. regulus (Hull) 221 M. rex Curran 222 M. senegalensis (Macquart) 223 M. simplicipes Curran 224 M. strigilatus (Bezzi) 225 M. sulcus sp. nov. 226 M. tarsatus (Bigot) 227 M. tibialis sp. nov. 228 M. vockerothi sp. nov.