Pseudexechia latevittata Chandler & Blasco-Zumeta, 2001

Kjaerandsen, Jostein, 2009, The genus Pseudexechia Tuomikoski re-characterized, with a review of European species (Diptera: Mycetophilidae), Zootaxa 2056, pp. 1-45 : 34

Pseudexechia latevittata Chandler & Blasco-Zumeta, 2001

( Figs 13 A–D)

Pseudexechia latevittata Chandler & Blasco-Zumeta, 2001:21 , figs 64–66

Diagnostic characters. From the two other European species of the trivittata group males are clearly distinguishable by having retained a narrow lamellate dorsointernal branch of the gonostylus, and by the sharp apical corners of the dorsal branch of the gonostylus. This species is, however, very close to P. macrocantha Kallweit, 1995 , described from Nepal (not seen). Based on the illustrations of P. macrocantha provided by Kallweit & Martens (1995), P. latevittata can be separated by the dorsal branch of the gonostylus that seems to have a less pointed apex, by the ventral branch of the gonostylus bearing two strong setae (as opposed to one in P. macrocantha ), and by the hypandrial lobe being more stretched with two long parallel branches medially (not truncated and converging apically like in P. macrocantha ). The female is also very similar to P. macrocantha , but seems to have more rectangular, truncated sternite VIII and tip of the postgenital plate.

Description. Male (n = 1). Body length 4.5 mm. Wing length 2.9 mm. Antenna length about 1.5 mm. Coloration (pinned specimen). Moderately bi-coloured in brown and yellow. Mesonotal stripes fused into dark, broad medial band; humeral area forming broad pale band along margin of mesonotum. Wings unmarked, yellowish tinted. Legs all pale. Abdomen dark with vague triangular, apical band on tergite II–IV, tergite V & VI all dark; terminalia yellow.

Head. Width / length to frontal tubercle 1.22–1.46. First flagellomere 3 times as long as second flagellomere. Second flagellomere 1.8 times as long as wide. Median ocellus vestigial or absent, lateral ocellus touching compound eye. Length / width of clypeus 1.2.

Thorax. Mesonotum length 0.94 mm, or 0.32 x as long as wing. Proepisternum with 1 strong bristle.

Wings. Wing length to length of R1 2.22; wing length to length of R5 1.63. Length of r-m to length of Mpetiole 1.08. R4+5-bending index 1.54. Fork length ratio 0.77. Fork width ratio 0.87. M-ratios 0.6 and 0.67. CuA-ratios 1.46 and 2.15. CuP length to length of wing 0.54. A1 length to length of wing 0.37.

Legs. Leg ratios not measured.

Terminalia ( Figs 13 A–C). Gonocoxite subrectangular, with distinct condyles; sternal sclerite forming elongated plate. Hypandrial lobe long, parallel sided, with sharp apices, deeply split. Aedeagal guides triangular. Gonostylus medium sized, elongated; dorsal branch subrectangular, with sharply truncated, whitish tip; dorsointernal branch forming narrow, elongated lamellate fan; medial branch reduced or fused with internal branch; ventral branch forming slender lobe with two strong setae a apex, covered with strong seta and 2 apical spines; internal branch forming large, striated cushion; anterior branch forming hyaline, irregular plate with one sclerotized projection caudally. Tergite IX long subrectangular, fused with weak mesal suture. Pseudocercus medium sized, setose. Cercus forming small knob, 1.67 as long as wide in dorsal view. Hypoproct reduced, hyaline. Epiproct vestigial or absent.

Female (not seen, re-description based on original description). Wing length 3.2 mm.

Coloration. As in male except, with vaguely yellow bands on all abdominal tergites.

Terminalia ( Fig. 13 D). Tergite VII widely excavated dorsally, with smooth, rounded posterior edge; apicolateral corner without nude area; setae along margin long. Tergite VIII wide, subrectangular. Tergite IX fused with postgenital plate. Cercus one-segmented, short sinusoid with obtuse tip. Postgenital plate (gonapophysis IX) short subsquare, with truncated tip. Sternite VII distinctly shorter than tergite VII. Sternite VIII subrectangular, truncate. Gonapophysis VIII not described.

Distribution. Known only by type material from Spain.

Biology unknown.

Type material examined: Holotype male, SPAIN: Zaragroza, Montenegros region, near Pina de Ebro, Retuerta de Pina, Juniperus thurifera wds., # 4225, 20 Nov 1991, Malaise trap [ BMNH, Leg. Blasco-Zumeta, JKJ – SPM –033621]. Pinned specimen in fairly good condition, with left wing partly damaged and both hind legs lost. Abdomen and terminalia mounted on separate slide.

Figures

FIGURE 13. Pseudexechia latevittata Chandler & Blasco-Zumeta, 2001. — A. Male terminalia, ventral view. — B. Male gonostylus, internal view, enlarged. — C. Male tergite IX and cerci, dorsal view. — D. Female terminalia (redrawn from Chandler & Blasco-Zumeta 2001), lateral view.