Mesembrius tibialis Jordaens, Goergen & De Meyer, 2021

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

publication ID	https://dx.doi.org/10.3897/zookeys.1046.57052
publication LSID	lsid:zoobank.org:pub:66E61C4E-FAFE-45DE-9145-DB38199BDEC3
persistent identifier	https://treatment.plazi.org/id/EB6378B6-C7E0-490B-B491-EC947BF4436A
taxon LSID	lsid:zoobank.org:act:EB6378B6-C7E0-490B-B491-EC947BF4436A
treatment provided by	ZooKeys by Pensoft
scientific name	Mesembrius tibialis Jordaens, Goergen & De Meyer
status	sp. nov.

Treatment

Mesembrius tibialis Jordaens, Goergen & De Meyer sp. nov. Figs 25 View Figures 25, 26 , 68 View Figures 64–69 , 105 View Figures 101–106 , 149 View Figures 147–150 , 156, 165 View Figures 163–165 , 177 View Figures 177–180 , 188 View Figures 185–188 , 227 View Figures 217–228

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.

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].

Paratypes: Togo • 2♂♂; Kloto Forest ; Dec 2017; G. Goergen leg.; IITA .

Description male

(Fig. 25 View Figures 25, 26 ). Body length: 14. mm. Wing length: 12.7 mm.

Head (Fig. 68 View Figures 64–69 ). 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.

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.

Legs. All legs chocolate-brown to black; distal ends black; other tarsi black. Proleg (Figs 156, 165 View Figures 163–165 ): 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 View Figures 177–180 ): Femur with long yellow pile posterodorsally; short black pile ventroproximally. Tibia curved; proximal half compressed. Metaleg (Fig. 188 View Figures 185–188 ): 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.

Wing (Fig. 149 View Figures 147–150 ). Entire wing uniformly dense microtrichose.

Abdomen (Fig. 105 View Figures 101–106 ). 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.

Genitalia (Fig. 227 View Figures 217–228 ). Epandrium: Dorsal lobe of surstylus short, broadly rounded; covered in short black spines and some longer pile. Ventral lobe of surstylus straight; bare.

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).