Revision of the Afrotropical species of the hover fly genus Mesembrius Rondani (Diptera, Syrphidae) using morphological and molecular data Author Jordaens, Kurt Royal Museum for Central Africa, Invertebrates Section and JEMU, Leuvensesteenweg 13, B- 3080 Tervuren, Belgium kurt.jordaens@africamuseum.be Author Goergen, Georg https://orcid.org/0000-0003-4496-0495 International Institute for Tropical Agriculture (IITA), Biodiversity Centre, 08 BP 0932 Tri Postal, Cotonou, Benin Author Skevington, Jeffrey H. https://orcid.org/0000-0002-1445-9870 Canadian National Collection of Insects, Arachnids and Nematodes, Agriculture and Agri-Food Canada, K. W. Neatby Building, 960 Carling Avenue, Ottawa, ON K 1 A 0 C 6, Canada Author Kelso, Scott Canadian National Collection of Insects, Arachnids and Nematodes, Agriculture and Agri-Food Canada, K. W. Neatby Building, 960 Carling Avenue, Ottawa, ON K 1 A 0 C 6, Canada Author Meyer, Marc De https://orcid.org/0000-0003-0755-2898 Royal Museum for Central Africa, Invertebrates Section and JEMU, Leuvensesteenweg 13, B- 3080 Tervuren, Belgium text ZooKeys 2021 2021-06-21 1046 1 141 http://dx.doi.org/10.3897/zookeys.1046.57052 journal article http://dx.doi.org/10.3897/zookeys.1046.57052 1313-2970-1046-1 66E61C4EFAFE45DE9145DB38199BDEC3 DBC42C98E4DA5074B86525CF2FB2FA64 Mesembrius tibialis Jordaens, Goergen & De Meyer sp. nov. Figs 25 , 68 , 105 , 149 , 156 , 165 , 177 , 188 , 227 Differential diagnosis. Mesembrius tibialis sp. nov. males have an apical pile brush on the profemur of thick, dense black pile dorsally and yellow pile ventrally. The metafemur is very long and slender and has long yellow pile and shorter yellow and black pile on the ventral side. The metatibia has no groove on the posterior side. The probasitarsus has a tuft of long black pile. The mesotibia is curved and the proximal half is compressed. The male differs from any other species in the colour of the apical pile brush (except from M. sulcus sp. nov.) which is black dorsally and golden-yellow ventrally (yellow-orange in M. chapini ; dark-brown to black in other species). It differs from M. sulcus sp. nov. in the orange and black probasitarsus (orange in M. sulcus sp. nov.), in the absence of a deep groove in the posterior proximal half of the metatibia and in the strongly compressed mesotibia (unmodified in M. sulcus sp. nov.). The female is unknown. Figures 177-180. Mesembrius spp., mesoleg, dorsal view 177 M. tibialis sp. nov. (♂) 178 M. caffer (Loew) (♂) 179 M. capensis (Macquart) (♂) 180 M. madagascariensis Keiser (♂). Abbreviations: bt-basitarsus, fem-femur, tib-tibia. Examined material. Mesembrius tibialis Jordaens, Goergen & De Meyer: Holotype , male " HOLOTYPUS " " Togo , Kloto Forest // II.2017 // leg. G. Goergen " " Mesembrius tibialis // Det. K. Jordaens " "DNA 1149A04 // K. Jordaens // RMCA 2019" [KMMA]. Figures 181-184. Mesembrius spp., mesoleg, dorsal view 181 M. senegalensis (Macquart) ( ♂ ) 182 M. caffer (Loew) ( ♂ ). Metaleg, posterior view 183 M. regulus (Hull) ( ♀ ) 184 M. rex Curran ( ♀ ). Abbreviations: bt-basitarsus, fem-femur, tib-tibia. Paratypes : Togo • 2♂♂ ; Kloto Forest ; Dec 2017 ; G. Goergen leg.; IITA . Figures 185-188. Mesembrius spp., mesoleg, dorsal view 185 M. perforatus (Speiser) ( ♀ ). Metaleg, posterior view 186 M. chapini Curran ( ♂ ) 187 M. sulcus sp. nov. ( ♂ ). Metaleg, ventral view 188 M. tibialis sp. nov. ( ♂ ). Abbreviations: bt-basitarsus, fem-femur, tib-tibia. Description male (Fig. 25 ). Body length: 14. mm. Wing length: 12.7 mm. Head (Fig. 68 ). Eyes bare; holoptic, eye contiguity approx. as long as length of ocellar triangle. Face yellow to orange with dark medial vitta; white pollinose; yellow-white pilose. Vertical triangle black; black pilose; yellow pollinose on medium third. Distance between lateral ocellus and eye margin slightly less than width of ocellus. Occiput black; yellow pilose with some shorter and thicker black pile near eye margin; white pollinose. Frontal triangle short; yellow-white; with some long black pile; white pollinose. Frontal prominence shiny black. Antenna black; postpedicel white pollinose; antennal arista orange-brown. Figures 189-192. Mesembrius spp., metaleg, posterior view 189 M. tarsatus (Bigot) (♂) 190 M. ingratus (Loew) (♂) 191 M. arcuatus sp. nov. (♂) 192 M. nigriceps Curran (♂). Abbreviations: bt-basitarsus, fem-femur, tib-tibia. Thorax. Scutum black with dorsally, in the anterior half, a pair of very faint yellow pollinose vittae. Scutellum black in anterior half, yellow-brown in posterior half; yellow pilose with, in the posterior half, some shorter black pile interspersed. Figures 193-196. Mesembrius spp., metaleg, dorsal view 193 M. platytarsis Curran syn. nov. (♂) 194 M. simplicipes Curran (♂). Metaleg, anterior view 195 M. caffer (Loew) (nominal morph) (♂) 196 M. caffer (Loew) (spined morph) (♂). Abbreviations: bt-basitarsus, fem-femur, tib-tibia. Legs. All legs chocolate-brown to black; distal ends black; other tarsi black. Proleg (Figs 156 , 165 ): Femur dorsoventrally flattened; with apical pile brush of long dense and curved thick black pile dorsally and thick yellow pile ventrally; ventrally with long black and shorter yellow pile. Tibia black; with long black pile. Basitarsus black and orange; with tuft of black pile on posterior side. Tarsi 2-4 black, tarsomere 5 white. Mesoleg (Fig. 177 ): Femur with long yellow pile posterodorsally; short black pile ventroproximally. Tibia curved; proximal half compressed. Metaleg (Fig. 188 ): Femur with very long and thin yellow pile, especially on anterior and posterior side; with shorter black pile ventrally and posteriorly. Tibia with long black pile; without groove on posterior side. 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. Wing (Fig. 149 ). Entire wing uniformly dense microtrichose. 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. Abdomen (Fig. 105 ). Tergite II with a pair of very large yellow, rounded maculae; black marking hourglass-shaped; yellow pilose except for short, black pile on the posterior black marking; posterior marking white pollinose. Tergite III and IV with orange fascia; short orange pile in medial part of tergites; long yellow-orange pilose on lateral sides; with white pollinose triangular posterior area. Figures 205-216. Mesembrius spp., male genitalia, lateral view 205 M. arcuatus sp. nov. 206 M. caffer (Loew) (nominal morph) 207 M. caffer (Loew) (spined morph) 208 M. ctenifer Hull syn. nov. 209 M. capensis (Macquart) 210 M. chapini Curran 211 M. copelandi sp. nov. 212 M. cyanipennis (Bezzi) 213 M. ingratus (Loew) 214 M. longipilosus sp. nov. 215 M. madagascariensis Keiser 216 M. minor (Bezzi). Genitalia (Fig. 227 ). Epandrium: Dorsal lobe of surstylus short, broadly rounded; covered in short black spines and some longer pile. Ventral lobe of surstylus straight; bare. 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. Female. Unknown. Distribution. Togo. Comments. This is a new species that is only known from three males from Kloto Forest, Togo. Etymology. The specific epithet Mesembrius tibialis is derived from the Latin word tibia (pertaining to the tibia) and was chosen in reference to the mesotibia, which is curved and proximally compressed. It is to be treated as an adjective (nominative singular masculine).