Paramixogaster trifasciatus, Ssymank & Reemer, 2016

Ssymank, Axel & Reemer, Menno, 2016, A new Afrotropical species of Microdontinae, provisionally placed in Paramixogaster (Diptera: Syrphidae), Acta Entomologica Musei Nationalis Pragae 56 (1), pp. 403-408 : 404-407

Paramixogaster trifasciatus sp. nov.

( Figs 1–11 )

Type locality. Central African Republic, 15 km east of Carnot, 620 m a.s.l., 04°58′N, 15°59′E.

Type material. HOLOTYPE: J, “ CENTRAL AFRICAN REP // 15 km E Carnot // N 04°58’ E 15°59’ // J. Halada leg. 5.6.2009 ”, “ Pseudomicrodon // spec. J // FO: 8047 // det. A. Ssymank 12.2012”, “? Paramixogaster // sp.n. // det. M. Reemer 2014 // Voucher code MR536”, ” HOLOTYPE // Paramixogaster // trifasciatus // Ssymank & Reemer [red label]” [genitalia placed in vial below the specimen] [ CZUP] . PARATYPE: ♀, “Central African Rep. // 60 km W Bouar // 05°45’N, 15°13’E // J. Halada, 23.III.2010 ” “ PARATYPE // Paramixogaster // trifasciatus // Ssymank & Reemer” [yellow label] [ ASWG].

Description. Male. Head ( Fig. 3 ). Eyes bare. Occiput ventrally narrow and dorsolaterally strongly widened resulting in 2 bulges, shiny black with long white pile. Frons and face shiny black with long white pile. Vertex with a transverse band of black pile from eye margin to eye margin; approximately equidistant, lateral distance between posterior ocellus and eye margin about the same as distance between the posterior ocelli. Lunula black. Oral margins and genae black. [Mouth parts and clypeus missing.] Antennae black, basoflagellomere longer than scape [exact length unknown as basoflagellomere is incomplete]; scape slightly longer than pedicel; arista brownish, inserted dorsolaterally close to base of basoflagellomere.

Thorax ( Figs 1, 2 ). Mesonotum shining black, finely punctate, with long white pile along anterior, lateral and posterior margins and sparse black pile medially [however, most pile in central part are wiped off (partially lacking) in type specimen, so pilosity hard to assess]; transverse suture incomplete, not visible medially on mesoscutum. Postpronotum and postalar callus brownish; white pilose. Scutellum brownish black, broadly rounded, ca 2 times as wide as long, with long white hairs (approx. half the length of scutellum) on disc and hind margin; without calcars. Halteres big, whitish. Sides of thorax shining brownish-black. Anepisternum long white pilose, except for ventral 1/4. Katepisternum dorsally with long white pile [ventral part of katepisternum not visible in holotype due to mounting]. Anepimeron long white pilose, katepimeron bare. Katatergum with long dark microtrichia. Anatergum with short dark microtrichia. [Metasternum not visible in holotype due to mounting.]

Wing. ( Fig. 1 ). Hyaline with dark pterostigma and 3 transverse dark bands, not reaching posterior wing margin: 1st basal band from apex of Sc including rm, bm-cu and posteriorly to the basal section of CuA1; 2nd median band beginning with a large rounded spot around posterior appendix of R 4+5 and extending to posterior end of dm-cu; 3rd apical band beginning at apex of R 2+3, ending at posterior end of M 1. Wing microtrichose, except for bare basal areas in cells c, sc, r, r 4+5, bm, br and dm. Stigmal crossvein present; length of posterior appendix of R 4+5 approx. 2/3 of width of cell r 4+5. Alula reduced: more than twice as long as wide. Base of costa (wing base) with a black elongated ventral flattend bulge with an apical tuft of very long black pile.

Legs. Femora brownish-black with narrow yellowish apex; white pilose, except hind femur with ventrally bare shiny strip. Tibiae basally whitish-yellow, front tibia only narrowly at base, mid tibia about basal 1/3 and hind tibia basal half; white pilose. Front and mid tarsus yellowish brown. Hind basitarsomere dark brown; yellowish pilose [other hind tarsomeres missing in holotype].

Abdomen ( Figs 1, 2 ). Whole abdomen shiny black, strongly constricted, narrowest at transition of tergite 2 and 3. Tergite 2 ca. 1.5 times as long as broad basally, apical width about 1/5 of basal width, dorsal medial keel from base to approx. 3/4 of its length, laterally at base and at apex with long white hairs. Tergite 3 in dorsal view shaped as equilateral triangle; short black pilose but apically with submedian patches of long white pile. Tergite 4 short black pilose with two large patches of yellowish white pile on apical half. Sternite 1 brownish, broadly oval, sterna 2–5 brownish black with short white pile, sterna 4 and 5 with longer apical white hair fringes.

Male genitalia ( Fig. 9 ). Phallus bent dorsad; furcate close to apex; processes equally long; projecting only little beyond apex of hypandrium; base spherical. Hypandrium without basolateral bulges and without lateral strips. Epandrium with ventrolateral ridges (see REEMER & STÅHLS 2013b for terminology).

Female ( Figs 4–7 , 10–11 ). Similar to male except for normal sexual dimorphism and:

Head ( Fig. 6 ). Frons with central small rounded non-pilose spot halfway between apical ocellus and base of antennae (in male holotype almost invisible). Oral margin and genae brownish-black, clypeus subquadrate and greyish pruinose. Antennae long black, basoflagellomere ca. 2 times as long as wide, length 0.48 mm, rounded at top and greyish dusted. Arista brownish, inserted dorsolaterally at ca. 1/4 of length from basoflagellomere, not reaching tip of basoflagellomere. Scapus elongated, ca. 2 times as long as broad, length 0.24 mm. Pedicel slightly broader than long, length 0.17 mm. Proboscis with rounded, small and yellowish labellum.

Thorax ( Figs 4, 5 ). Mesoscutum shiny black, finely punctate with long white pile along apical and posterior margin just before scutellum; broad band of black pile between wing bases almost extending to scutellum. Sides of thorax shiny brownish-black; katepisternum dorsally with long white pile, medially and ventrally bare shiny brown. Metasternum bare.

Wing. No differences from male holotype.

Legs. Front and mid femur with dense basoventral patches of short orange hairs reaching up to cicatrice, otherwise short whitish dispersed pile. Front and mid tarsus brownish black. Hind metatarsus about as long as remaining 4 apical tarsal joints together.

Abdomen ( Figs 4, 5, 7 ). Whole abdomen shiny black, strongly constricted. Tergum 2 ca. 1.5 times as long as broad basally, apical width about 1/2 of basal width, dorsal medial keel from base almost to distal end, basal 2/3 with lateral transverse wrinkles, laterally at base and at apex with long white pile. Tergum 3 strongly broadened ca. 4 times broader apically than basally. Terga 3 and 4 basally and medially short black pilose, apically with submedian patches of long white pile. Terga 5 and 6 largely white pilose. Metacoxal bridge very narrowly connected ( Fig. 7 ).

Length. Body: 9.19 mm (holotype), 9.12 mm (paratype); wing 6.12 mm (holotype), 6.00 mm (paratype).

Differential diagnosis. Among the known Afrotropical Microdontinae with constricted abdomen, Paramixogaster trifasciatus sp. nov. is the only taxon with three dark fasciae on the wing. Within Paramixogaster this is the only known species with a pilose postpronotum.

Etymology. The specific epithet is a composed Latin adjective trifasciatus (- a, - um), having three stripes, given in reference to the three dark bands on the wing.

Biology. Altitude of locality of PT according to Google Earth is ca. 670 m a.s.l., open tree savanna.

Distribution. Only known from Central African Republic.

Figures

Figs 1–8. Paramixogaster trifasciatus sp. nov. 1–3 – male holotype: 1 – dorsal view; 2 – lateral view; 3 – frontal view. 4–7 – female paratype: 4 – dorsal view; 5 – lateral view; 6 – frontal view; 7 – ventral view with metacoxal bridge. 8 – male holotype labels.

Figs 9–11. Paramixogaster trifasciatus sp. nov. 9 – male holotype, genitalia; 10 – female paratype, antenna; 11 – female paratype, labels.