Phyllodromia variabilis, Plant & Daugeron, 2009

Plant, Adrian R. & Daugeron, Christophe, 2009, A new species of Phyllodromia Zetterstedt, 1837 (Insecta, Diptera, Empididae, Hemerodromiinae) from Vanuatu, Zoosystema 31 (3), pp. 519-524 : 520-522

Phyllodromia variabilis n. sp.

( Figs 1 ; 2 )

TYPE MATERIAL. — Vanuatu. Espiritu Santo , Penaoru, 1200 m, ground, Malaise, montane forest, 8-18.XI.2006, ♂ holotype ( MNHN). — Same data as holotype, 25 ♂♂ paratypes, 16 ♀♀ paratypes ( MNHN) ; 15 ♂♂ paratypes, 14 ♀♀ paratypes ( NMWC NMW.Z.2008.050) .

ETYMOLOGY. — The specific epithet refers to the variable colouration of the thorax and variation in size of the species.

DESCRIPTION

Male

Body length 2.0- 2.2 mm.

Head black with greyish dust, rather dorsoventrally compressed. Ocellar tubercle bearing a few minute setulae and a pair of strong black divergent ocellar setae. A pair of minute frontal setulae, widely separated at front of frons. Face whitish, very narrow about as wide as single ommatidium immediately below eye and widening toward mouth. Two pairs of vertical setae, inner vertical contiguous with upper series of postocular setae. Postocular setae black on upper occiput, becoming yellow below and on lower occiput, merging into patch of yellow erect pile on gena.

Antenna black with basal segments yellow; postpedicel sharply pointed lanceolate, almost twice as long as deep, stylus about 3 times as long; scape with strong dorsal seta extending beyond apex of pedicel which bears circlet of shorter black setulae, longest on outer face. Mouthparts yellow, proboscis darker apically; palpus narrow with a few longish fine setae apically and on outer face.

Thorax. Colour pattern highly variable, usually broad median brown stripe on scutum which is sometimes considerably narrowed or virtually absent and occasionally broader leaving only extreme lateral margins of scutum yellowish. In paler examplars brownish cloud often present above humerus, weakly continued posteriorly over notopleural depression. Scutellum and postnotum dorsally brownish. Pleura clear yellow, occasionally suffused brownish. All thoracic setae black; anterior dorsocentral minute, positioned close to anterior margin of scutum in dorsal view; second dorsocentral strong, in line with somewhat weaker postpronotal seta; pair of convergent scutellar setae, one supraalar and upper notopleural about as long as postpronotal; posthumeral, lower notopleural and postalar setae smaller. Pair of minute acrostichals and some minute setulae in front of postpronotal seta and on proepisternum and katepisternum above base of front coxa. Laterotergite with 3-6 upswept setae.

Legs yellow with apical tarsal segments darker (especially blackish tarsomeres 4 and 5). Front coxa about 0.95 times as long as thorax, bearing a few decumbent bristly setae anteriorly and posteriorly. Mid and hind coxae short, former with anteroapical fan of dark setae, latter with 2 or 3 stouter yellowish setae anteroapically. Front femur inflated, about 4.5 times as long as wide, widest 0.2 from base, narrowing distally; armed ventrally on distal 0.9 with an anteroventral series of 13- 16 (mean = 13.8 ± 1.2, n = 11) rather regularly spaced black spine-like setae, becoming shorter distally but with a few shorter setae interspersed in series proximally; posteroventral series of 9-12 (mean = 10.3 ± 0.8, n = 11) similar rather less regularly spaced setae, longest proximally but with distal 3 or 4 very small and closely spaced; no rows of peg-like denticles between anteroventral and posteroventral setation; one single strong basal anteroventral seta; anterior surface bare, one or two outstanding dark setae dorsally and apically but otherwise with only short decumbent setulae. Front tibia linear, about 0.8 times as long as front femur and articulating between two rows of spine-like ventral setae on femur. Legs otherwise simple with short setae but posterior femur slightly inflated and curved with a few erect black setulae amongst dorsal ciliation.

Abdomen brown dorsally, paler ventrally.Tergites 1-7 with distinct short setae sparsely on disc and posterior margins; tergite 2 slightly elongated; tergite 8 very narrow. Male terminalia ( Fig. 2 ) dark brown, reflexed upward at 90°. Epandrium and hypandrium separate, nowhere fused.Hypandrium divided medially by broad pale membranous area with short dark setae along posterior margin of outer more sclerotized lobes ( Fig. 2B ). Epandrium divided, subrectangular in lateral view ( Fig. 2C ); a weakly developed apical lobe delineated by white weakly sclerotized area posteriorly; with distinct setae including one rather longer on posterior margin subapically. Subepandrial sclerite strongly sclerotized, long bifid subepandrial process arising dorsally ( Fig. 2A ); posterior bifurcation narrow, emerging slightly beyond tip of epandrium in lateral view and strongly curved posteriorly; anterior bifurcation broader in lateral view with anteriorly twisted rather beak-like apex; both bifurcations narrower in anterior and posterior view. Pale yellow rod-shaped process (phallic process?) each side of phallus, apically divergent viewed from in front or behind but in lateral view rather abruptly curved posteriorly near apex. Postgonites somewhat beak-shaped apically, broad, almost transparent and very inconspicuous. Phallus pale, broad, curving posteriorly near tip. Cercus very small, free, very inconspicuous but covered with distinctly bent setae and shorter setulae.

Wing with membrane tinged brown, veins yellowish brown. Fork M 1 + M 2 narrow. Crossvein dm-cu absent.Cell cup (anal cell) closed and slightly produced posteriorly, vein CuA 2 closing cell linear. Vein A 1 distinct for short distance beyond end of cell cup. Squamae with dark fringes, halter brownish white.

Female

Very similar to male but larger, body length 2.5- 3.2mm. Front femur with 10-15 (mean = 12.5 ± 1.5, n = 11) spine-like setae in anteroventral series and 10-14 (mean = 11.1 ± 1.3, n = 11) in posteroventral series. Abdomen with tergites brown bearing sparse and inconspicuous short pale setulae, longer and darker on posterior margins; basal sternites whitish but sternites 8 and 10 brown, the former slightly elongated, terminally trapezoid and with distinct fine marginal setae, the latter very small bearing a few fine setulae. Cercus rather slender, brown, with a few longish fine setulae on outer face and apically.

Figures

FIG. 1. — Phyllodromia variabilis n. sp., male habitus. Scale bar: 1.0 mm.

FIG. 2. — Phyllodromia variabilis n. sp. male terminalia: A, anterior aspect; B, posterior aspect; C, lateral aspect. Abbreviations: cer, cercus; ep, epandrium; hyp, hypandrium; pg, postgonite; ph, phallus; pp, phallic process; subep, subepandrial process. Scale bar: 0.1 mm.