New species of Platypalpus (Diptera: Hybotidae) from the Democratic Republic of the Congo

. Six new species of Platypalpus Macquart, 1827 are described from tropical forest at Yangambi (Democratic Republic of the Congo): Platypalpus bolikoi sp. nov., P. ikoso sp. nov., P. lokonda sp. nov., P. manjano sp. nov., P. saffradi sp. nov. and P. yangambensis sp. nov. All species are photographed and, except for P. saffradi sp. nov. known only from females, male terminalia are illustrated for all. A key is provided for the six species of DR Congo. COI barcodes are available for all species at GenBank.


Introduction
The genus Platypalpus Macquart, 1827 is the largest group of the Hybotidae subfamily Tachydromiinae and one of the most speciose genera of Empidoidea on the whole. Currently about 550 species of Platypalpus are known worldwide but about 75% of them were described from the Palaearctic and Nearctic regions (Yang et al. 2007). In the Afrotropical Region only 28 species are known. The fi rst species was described by Loew (1858) from South Africa; Becker (1914) described three species from Kenya; Collin (1922) described a single species from the Seychelles; Smith (1967a) described fi ve species from Tanzania and eighteen species from South Africa (Smith 1967b(Smith , 1969. Only South African species of Platypalpus have been keyed. The present paper is the result of a short sampling campaign at the end of May and fi rst half of June 2013 in the surroundings of Yangambi (DR Congo, Oriental Province) at an altitude of about 400 m. The collection was made at the beginning of the 'short dry season' and indeed it did not rain at all during the campaign. Collections were made in a patchwork of forest types ranging from garden patches, bamboo, over young forest to mixed primary and monodominant (Gilbertiodendron J.Léonard) forest. The study was in the scope of the PODO project COBIMFO (Congo Basin Integrated Monitoring for Forest Carbon Mitigation and Biodiversity) in which a relation is being sought between carbon fi xation and biodiversity. The aim of this project is to get baseline reference data on the Carbon balance and biodiversity in pristine and intervened dense tropical forests of the Congo Basin and to increase our understanding of the relationship between both variables as a function of forest management.
Only thirteen specimens of Platypalpus were found out of a total of about 1600 Tachydromiinae showing how rare Platypalpus is. However, they belong to six species all new for science. Moreover Platypalpus is here reported for the fi rst time from DR Congo.
The present study is also the continuation of a major review of the Hybotidae of DR Congo that was started in 2010 (Grootaert & Shamshev 2013).

Material and methods
The holotypes will be housed in the Collections of the Centre de Surveillance de la Biodiversité in Kisangani (DR Congo) as soon as the facilities will be fully operational, but are now temporarily deposited in the Royal Belgian Institute of Natural Sciences, Brussels, Belgium (RBINS). In the descriptions we cite under 'reg.' the register number that is a unique identifi er referring to the locality, date and microhabitat. When we cite the holotype we indicate also the MS name or code that was used throughout the description process e.g. 'Plat3' is the third Platypalpus species found in the Congo samples. All specimens were collected by the fi rst author (PG) by sweep netting and are conserved in 70% ethanol. The specimens from which DNA was extracted are conserved in our tissue collection at RBINS with the cuticular parts still being recognisable. We refer to the barcode of the tube in the tray in which it is conserved: e.g. 'tube AB31515301' stored in tray called 'Congo2'.
The terminology and descriptive format used in the descriptions follow Grootaert & Shamshev (2012). In describing the sclerites of the thorax the terminology used by previous authors is often indicated in brackets. The scale bar represents 0.1 mm, but this is only an indicative measure because the drawings are projections of structures that are usually not in a horizontal plane.

Abbreviations
The following abbreviations are used in the illustrations: a = apodeme lc = left cercus lel = left epandrial lamella rc = right cercus rel = right epandrial lamella rs = right surstylus.

Diagnosis
Small black species of the pallidiventris-cursitans group. One pair of verticals. Postpedicel short, 1.5 times as long as wide. Thorax faintly tomentose on scutum. Legs including all coxae yellow, but mid femur brownish dorsally and hind femur dark brown on apical 2/3, apical half of tarsomere 5 of all legs brownish; large pointed apical spur on mid tibia.

Etymology
The species is dedicated to Mr. Lola Boliko, who guided the fi rst author in the forest during the expedition in 2013.  HEAD. Entirely black. Occiput densely greyish pollinose; with 1 pair of long yellow verticals. Ocellar tubercle greyish pollinose, with subequally very short anterior and posterior setae. Frons broad, somewhat broadened toward ocellar tubercle, subshining. Face narrow, greyish pollinose, clypeus subshining. Antenna with scape and pedicel brown, postpedicel and stylus yellowish brown; postpedicel small, ovoid, 1.5 times as long as wide; stylus 1.8 times as long as postpedicel. Proboscis pale yellowish brown, shorter than head is high. Palpus pale yellow, large, elongate ovate, with scattered pale setulae.
LEGS. Largely reddish yellow, but mid femur brownish dorsally, hind femur dark brown on about apical 2/3, tarsomere 5 of all legs yellowish brown apically. Coxae and trochanters with ordinary yellowish to brownish yellow setae of different lengths. Fore femur thickened; with rows of short anteroventral and posteroventral setae. Fore tibia rather slender, clothed with ordinary setulae. Mid femur very thickened; with double row of black ventral spinules and row of long, yellow posteroventral setae. Mid tibia bearing a row of black ventral spinules; with long pointed largely black apical spur. Hind femur slender, with short anteroventral setae. Hind tibia slender, clothed with ordinary setulae. Tarsi of all legs unmodifi ed.
WING. Hyaline, with brownish veins. One moderately long black costal seta. Veins R 4+5 and M 1+2 somewhat convergent just before meeting wing margin. Crossveins m-cu and r-m separated; cell bm longer and somewhat broader than cell br; Vein CuA 2 straight. Anal vein evanescent in apical part and lacking in basal part. Calypter brown, with brown setae. Halter brownish.
ABDOMEN. With tergites brownish, subshining, covered with faint very short setae; sternites brownish, with similar setae; segment 8 with several moderately long yellowish brown posteromarginal setae. Terminalia rather small, brown . Both cerci digitiform, equally long, shorter than right epandrial lamella. Right and left epandrial lamella equally long, set with unmodifi ed setae. Only short setae of left border of left epandrial lamella.

Female
Unknown.

Comparison
In the key of Smith (1969) the new species runs to P. vicina Smith, 1969 that was described from South Africa. In the latter species the fore femur is darkened above while in P. bolikoi sp. nov. the fore femur is entirely yellow. In P. vicina the mid and hind coxae are darkened. Here they are yellow. Platypalpus soror Smith, 1969 has a black proboscis and yellow halteres. In the new species the proboscis is pale and halteres are brown.

Diagnosis
A medium-sized species of the albiseta-group. Postpedicel 5.3 times as long as wide; stylus white, 1.6 times as long as postpedicel. Legs reddish-yellow. Mid femur with a short fl attened apical spur.

Etymology
The specifi c epithet 'ikoso' means fl y or mosquito in Tumburu, the local language spoken at Yangambi.
HEAD. Entirely black. Occiput densely greyish pollinose; with 1 pair of long black verticals. Ocellar tubercle greyish pollinose, with 2 black, moderately long anterior and 2 very short posterior setae. Frons narrow, somewhat broadened toward ocellar tubercle, above antennae slightly broader than anterior ocellus, greyish pollinose. Face narrow, on middle as broad as anterior ocellus, somewhat broader below antennae and on lower part, greyish pollinose, clypeus subshining. Antenna with scape, pedicel and postpedicel brown; postpedicel conical, long, 5.3 times as long as wide; stylus white, long pubescent, 1.6 times as long as postpedicel. Proboscis brownish yellow, rather long, somewhat shorter than head is high. Palpus brownish yellow, small, ovate, with scattered dark setulae.
LEGS. Largely reddish yellow, fore and hind tibiae, entire fore tarsus, apical tarsomeres of mid and hind tarsi rather brownish yellow. Coxae and trochanters with ordinary yellowish to brownish yellow setae of different lengths. Fore femur slender; with rows of thin anteroventral and posteroventral setae shorter closer to apex, the latter including 2 longer brownish setae closer to base. Fore tibia slender, clothed with ordinary setulae. Mid femur (Fig. 7) very thickened, long; with double row of black ventral spinules and row of long, black posteroventral setae. Mid tibia bearing a row of black ventral spinules; with short fl attened apical spur. Hind femur slender, with short anteroventral setae. Hind tibia slender, clothed with ordinary setulae. Tarsi of all legs unmodifi ed.

Female
Unknown.

Comparison
In the key of Smith (1969) Platypalpus ikoso sp. nov. runs to P. inermifemur Smith, 1969 andP. ngomensis Smith, 1969 both described from South Africa. In P. inermifemur the ratio of second and third sections of vein Cu (fi fth vein sensu Smith 1969) is 3 : 3.5 and the hind femur is without distinct anteroventral setae. In P. ngomensis the ratio of second and third section of vein Cu is 2 : 3.5 and the hind femur bears short, but distinct anteroventral setae. In P. ikoso sp. nov. the apical section of vein Cu is twice as long as the second section being 2 : 4, which is comparable to P. ngomensis. The femur bears distinct anteroventral setae that are half as long as femur is wide. In P. ngomensis the left epandrial lamella is about as long as the right epandrial lamella. In P. ikoso sp. nov. the left lamella is very short (Fig. 12). In addition vein Cu does not reach the wing border in P. ikoso sp. nov. and P. ngomensis, but it does in P. inermifemur.

Diagnosis
A medium-sized species of the albiseta-group. One pair of long vertical bristles. Antenna black, postpedicel nearly 4 times as long as wide; with white stylus, almost 2.5 times as long as postpedicel. Mesonotum dark brown; pleura brown. Mid tibia with short pointed apical spur.
LEGS. Yellow. Coxae and trochanters with ordinary yellowish to brownish yellow setae of different lengths. Fore femur slender; with rows of anteroventral and posteroventral yellowish setae longer on basal part. Fore tibia slender, clothed with ordinary setulae. Mid femur (Fig. 17) very thickened; with double row of black ventral spinules and row of long, brownish yellow posteroventral setae. Mid tibia bearing a row of black ventral spinules; with short fl attened apical spur. Hind femur slender, with short anteroventral setae. Hind tibia slender, clothed with ordinary setulae. Tarsi of all legs unmodifi ed. WING. (Fig. 16). Faintly infuscate, with brownish veins. One moderately long costal seta. Veins R 4+5 and M 1+2 convergent just before meeting wing margin. Crossveins m-cu and r-m contiguous; cell bm somewhat longer and broader than cell br. Vein CuA 2 sinuate. Anal vein distinct in apical part and evanescent in basal part. Calypter brown, with brown setae. Halter brownish.

Female
Unknown.

Comparison
Platypalpus lokonda sp. nov. is very closely related to P. ngomensis Smith, 1969 described from Natal, South Africa. It differs in having brown prothoracic sterna and propleura which are yellow in P. ngomensis. In the latter species, the left epandrial lamella is about as long as the right epandrial lamella, in P. lokonda sp. nov., the left lamella is very short.

Diagnosis
A medium-sized yellow species of the albiseta-group. Postpedicel brown, a little more than 5 times as long as wide; stylus white, about as long as postpedicel. Mid tibia with short yellow apical sharp spur, shorter than tibia is wide.

Etymology
The word 'manjano' means yellow in Turumbu, language that is spoken in Yangambi. It refers to the yellow body colour of the new species. HEAD. Entirely black. Occiput greyish pollinose; with 1 pair of long black verticals. Ocellar tubercle greyish pollinose, with 2 black, short anterior and 2 minute posterior setae. Frons very narrow, somewhat widened toward ocellar tubercle, above antennae nearly as broad as anterior ocellus, greyish pollinose. Face very narrow, narrower than anterior ocellus, greyish pollinose, clypeus subshining. Antenna with scape, pedicel and postpedicel brown; postpedicel conical, long, 5.3 times as long as wide; stylus white (except basal segment), long pubescent, about as long as postpedicel. Proboscis brownish, long, nearly as long as head is high. Palpus yellow, small, ovate, with scattered setulae and a long brownish subapical seta.
LEGS. Almost entirely yellow, except for fore tibia and apical four tarsomeres more brownish than fore femur; mid and hind leg with only apical tarsomere brownish. Coxae and trochanters with ordinary yellowish to brownish setae of different lengths. Fore femur slender; with very short anteroventrals and 4 fi ne moderately long brownish posteroventral setae on about basal half. Fore tibia slender, clothed with ordinary setulae. Mid femur very thickened; with double row of black ventral spinules and row of long, black posteroventral setae (Fig. 24). Mid tibia bearing a row of black ventral spinules; with very short fl attened apical spur. Hind femur slender, with short anteroventral setae. Hind tibia slender, clothed with ordinary setulae. Tarsi of all legs unmodifi ed. WING. (Fig. 22) Finely, uniformly infuscate, with brownish veins. Costa between R 1 and R 2+3 darkened. One moderately long costal seta. Veins R 4+5 and M 1+2 almost parallel just before meeting wing margin. Crossveins m-cu and r-m contiguous; cell bm longer and distinctly broader than cell br; Vein CuA 2 somewhat sinuate reaching wing border. Anal vein distinct in apical part and evanescent in basal part. Calypter brown, with about 10 brown setae. Halter darkened.

Female
Unknown.

Comparison
In Smith's (1969) key the new species runs to P. rhodesiensis Smith, 1969 that was described from females found in Rhodes-Inyanya National Park in Zimbabwe. However the latter has scape and pedicel yellow. In P. manjano sp. nov. the scape and pedicel are brown. In P. rhodesiensis the scutellum is reddish yellow, but blackish on disc and sometimes completely black. In the new species the scutellum is yellow.

Diagnosis
A medium-sized yellow species of the minutus-group with thorax and legs yellow, but all coxae white; abdomen with tergites 1-5 brownish. No postpronotal (= humeral) seta present. One pair of vertical bristles. Scape and pedicel black; postpedicel brown, 2.5 times as long as broad; stylus brown. Mid tibia with long, but blunt apical spur.

Etymology
The word 'saffradi' means yellow in Swahili language and it refers to the yellow body colour of the new species.
LEGS. Almost entirely yellow, only last tarsomere brownish yellow. Coxae and trochanters almost white, with ordinary yellowish to brownish yellow setae of different lengths. Fore femur thickened; with uniformly very short anteroventral and posteroventral setae. Fore tibia slender, clothed with ordinary setulae somewhat longer dorsally. Mid femur (Fig. 31) very thickened, long; with double row of black ventral spinules and row of long, yellow posteroventral setae, longest near middle as long as femur is wide. Mid tibia bearing a row of black ventral spinules; with long blunt-tipped apical spur bearing short seta. Hind femur slender, with short anteroventral setae. Hind tibia slender, clothed with ordinary setulae. Tarsi of all legs unmodifi ed.
WING. Finely, uniformly infuscate, with brownish veins. One moderately long costal seta. Veins R 4+5 and M 1+2 parallel just before meeting wing margin. Crossveins m-cu and r-m narrowly separated; cell bm longer and distinctly broader than cell br; Vein CuA 2 recurrent, somewhat sinuate. Anal vein distinct in apical part and evanescent in basal part. Calypter darkened, with brown setae. Halter darkened.

Male
Unknown.

Comparison
In the key of Smith (1969), P. saffradi sp. nov. runs to P. eshowensis Smith, 1969 described from Zululand (South Africa). In the latter species the frons is wider (2.5 times ocellar width), face below antenna about 1.5 times ocellus and there is a distinct fi ne humeral seta. In P. saffradi sp. nov. the frons is narrower (only 1.5 times the width of anterior ocellus), face is almost linear and there is no distinct humeral seta. Platypalpus eshowensis has a long sharp apical spur on mid tibia, while it is long, but blunt in P. saffradi sp. nov. with a black bristle at tip. Finally the apical two tarsomeres of all legs are darkened while in P. saffradi sp. nov. only the apical half of the apical tarsomere is brownish.
Platypalpus saffradi sp. nov. is provisionally placed in the minutus-group because of the presence of a well-developed postpronotal lobe lacking however a distinct postpronotal seta. Mesonotum is polished and mid tibia bears a long apical spur.

Diagnosis
A medium-sized black species of the minutus-group with two pairs of indistinct vertical bristles. Scutum shining black; pleura brownish black dusted but katepisternum largely polished. Legs yellow but mid femur with narrow ventral brown stripe that is shortly interrupted near middle and hind femur a black ring in middle. Mid tibia half as long as femur, with a strong sharp spur.

Etymology
The specifi c epithet refers to the type locality, Yangambi.

Paratypes
1 ♂ from same provenance as holotype (RBINS); 1 ♂ with same provenance as holotype in tray Entomo001 at position E4, completely extracted with barcode AB48937135 (RBINS); 1 ♂ with same provenance as holotype with mid leg in tray Entomo004 at position A3 with barcode AB42406113 has been extracted for DNA (RBINS); HEAD. Entirely black in ground-colour. Occiput entirely faintly greyish pollinose; with 2 pairs of dark very short verticals (hardly distinguished from other occipital setae), further clothed with short bristly hairs, longer setae on lower part. Ocellar tubercle greyish pollinose, with 2 dark, short anterior and 2 minute posterior setae. Frons widened toward ocellar tubercle, above antennae nearly 1.5 times as broad as anterior ocellus, shining. Face narrow, greyish pollinose, clypeus subshining. Antenna (Fig. 33) with scape and pedicel black, postpedicel brown; postpedicel conical, about 3.0 times as long as wide; stylus dirty white, nearly 1.5 times as long as postpedicel. Proboscis brownish, long, nearly as long as head is high. Palpus (Fig. 33) yellow, ovate, short, with scattered setulae and a long, brown subapical seta.
LEGS. Almost entirely yellow; fore and hind coxae and trochanters almost white; mid coxae yellowish; mid femur with narrow ventral brown stripe (interrupted before middle), hind femur with broad brownish ring on apical part leaving narrow subapical space yellow, knees of mid and hind legs brownish. Coxae and trochanters with ordinary yellowish to brownish setae of different lengths. Fore femur moderately thickened, with minute pale brown anteroventral and posteroventral setae; a strong brown posterior seta near base of femur. Fore tibia very thickened, spindle-shaped, clothed with ordinary setulae. Mid femur ( Fig. 35) about 1.5 times stouter and almost twice longer than fore femur; with double row of black ventral spinules and row of long, brown posteroventral setae. Mid tibia about half as long as femur, with long pointed apical spur bearing 2 subapical setulae of different lengths. Hind femur slender, with short anteroventral setae. Hind tibia slender, clothed with ordinary setulae. Tarsi of all legs unmodifi ed.
WING. (Fig. 34). Finely, uniformly faintly infuscate, with brownish veins. One short black costal seta. Veins R 4+5 and M 1+2 convergent just before meeting wing margin. Crossveins m-cu and r-m separated; bm longer and slightly broader than br. Vein CuA 2 somewhat sinuate, not recurrent. Anal vein distinct in apical part and evanescent in basal part. Calypter brown, with brown setae. Halter darkened.