Macrostomus flavus, Rafael & Cumming, 2009

Rafael, José Albertino & Cumming, Jeffrey M., 2009, Revision of the genus Macrostomus Wiedemann (Diptera: Empididae: Empidinae). I. The ferrugineus species-group, Zootaxa 2064 (1), pp. 39-56 : 50-52

Macrostomus flavus , n. sp.

( Figs. 6a–m , 9 )

Diagnosis. Thorax, abdomen and legs predominantly yellow; postcranium black with gray pruinescence; male tergite 8 with distal projection truncated. Female hind tibia with short pinnate scales dorsally.

Description. Holotype male. Frons approximately three quarters anterior ocellus width. Face as wide as frons. Postcranium entirely black. Antenna with scape and pedicel yellow; flagellum velvety black, sometimes yellowish at base. Palpus yellow. Thorax shining yellow with yellow to gray-brown pruinescence. Setae: 4 dorsocentrals (sometimes 3); 1 supra-alar presutural; 2 pairs of scutellars; 3–6 antepronotals; 2–3 tiny proepisternals; 3–6 katatergitals. Legs yellow with distal tarsomeres 3–5 or 4–5 brown. Mid tibia with 1–3 dorsal setae slightly stout at median third; hind tibia with 3–4 slender dorsal setae; first hind tarsomere with one longer dorsal seta. Wing with pterostigma brown infuscated and narrow apex light brown infuscated ( Fig. 6a ). Halter with stem yellow, knob yellow to dark brown. Abdomen shining yellow with black terminalia. Tergite 8 ( Fig. 6b ) with blunt truncated projection distally. Epandrium with wider anterodorsal and thinner posterodorsal protuberances of subequal length ( Fig. 6c ). Anterior cercus somewhat elongate; posterior cercus blunt distally, serrated along anterior margin, with a few setae on small anteriorly directed lobe and two bifid internal protuberances, with anterior one longer and posterior protuberance smaller ( Fig. 6d ). Hypandrium ( Fig. 6e ) with a few setae on basal half, two paired apical protuberances and keel-shaped subapical process medially.

Size. Body length 3.0 mm; wing length 3.2 mm.

Female. Frons slightly wider than anterior ocellus width. Face narrower than frons, approximately three quarters of anterior ocellus width. Apex of hind tibia and first hind tarsomere black. Mid tibia with 1–2 slightly stout dorsal setae at median third; hind tibia with short dorsal pinnate scales ( Fig. 6f ). Wing wider than in male, more distinctly infuscated in the same areas ( Fig. 6g ). Terminalia black, sparsely gray pruinose. Tergite 8 and sternite 8 as in Figs. 6h–j . Genital fork as in Figs. 6k–l . Spermatheca as in Fig. 6m .

Size. Body length 3.1; wing length 3.3 mm.

Geographical records. Brazil (Roraima, Amazonas states), Fig. 9 .

Material: holotype ♂, BRASIL, Amazonas , Manaus , PDBFF /WWF, Proj [eto] Bert Klein // ix.1985 ,

Malaise // Reserva 1301 (INPA).

Paratypes: Manaus, PDBFF / WWF, Proj. Bert Klein, ix.1984, Reserva 1210 (1♂ INPA); Manaus, PDBFF / WWF, Proj. Bert Klein, iv.1985, Reserva 1301 (1♂ CNC); Manaus, PDBFF / WWF, Proj. Bert Klein, viii.1985 (1♂ INPA); Manaus, PDBFF / WWF, Proj. Bert Klein, ix.1985 (1♂ CNC); Manaus, PDBFF /WWF, Proj. Bert

Klein , xi.1985 (2♂ CNC) ; Manaus , PDBFF /WWF, Proj. Bert Klein, iii.1987, Reserva 1208 (1♂ INPA) ; F.P. Alegre, BR 174 , km 68, 17–21.i.1994, F.F. Xavier (1♀ INPA) ; Reserva Ducke , AM 010 , km 24, 02–07.ix.1996 (1♀ CNC) ; P.N. Jau, Rio Carabinani , 16.iv.1994, Ruth & Ricardo (2♀ INPA) ; Igarapé Preguição , 20–29.vi.1994, L.S. Aquino (2♂ INPA, 1♂ CNC) ; Igarapé Miratucu , 015702S–614901W, 23–28.vii.1995, J.A. Rafael & J. Vidal, varredura (1♀ CNC) ; Rio Unini , Democracia, 014354S–615432W, 20–24.vi.1996, A.L. Henriques, J. Vidal & F.L. Oliveira, arm. Malaise (1♀ CNC) ; Roraima , Rio Uraricoera, Ilha de Maracá, 05–15.x.1987, L.S. Aquino, arm. Malaise (3♂, 2♀ INPA) .

Holotype condition. Good, not dissected.

Etymology. From Latin flavus = yellow, in reference to the yellow color of specimens.

Discussion. Macrostomus flavus appears close to M. furcatus on the basis of a first hind tarsomere with 1–4 slender setae dorsally and presence of pinnate scales on the female hind tibia. It differs from M. furcatus by the male tergite 8 being truncate at the apex rather than forked, and by the presence of pinnate scales on only the dorsal surface of the female hind tibia instead of on both the dorsal and ventral surfaces as in M. furcatus .

Figures

FIGURE 6. Macrostomus flavus, n. sp., paratypes from Roraima. A–E, male; A, wing; B, tergite 8, dorsal view with right setae omitted; C, terminalia, lateral view; D, detail of posterior cercus; E, hypandrium and phallus, lateral view. F–L, female; F, hindleg, posterior view; G, wing; H, distal abdominal tergites, dorsal view with right setae omitted; I, distal abdominal segments, lateral view; J, distal abdominal sternites, ventral view with left setae omitted; K–L, genital fork in lateral and ventral view; M, spermathecae. Scales: F = 0.5 mm; B–C,E,H–J = 0.2 mm; K–M = 0.1 mm.

FIGURE 9. Distribution map of species belonging to the Macrostomus ferrugineus species-group with tergite 8 truncated or forked distally. Symbols represent the known collection localities as follows: diamond = M. longipennis, n. sp.; open circle = M. furcatus, n. sp.; open triangle = M. flavus, n. sp.; square = M. fulvithorax; star = M. occidentalis.