Phytobia pseudobetulivora Zlobin

Zlobin, Vladimir V., 2008, Review of mining flies of the genus Phytobia Lioy (Diptera: Agromyzidae): Western Palearctic species, Zootaxa 1725, pp. 61-66 : 61-63

Phytobia pseudobetulivora Zlobin , sp.n.

( Figs 1–3 )

Female. Frons parallel-sides, as long as broad at level of anterior ocellus, twice width of eye, distinctly projecting above eye margin in profile, increasingly so towards antennal bases. Frontal plate ill differentiated. Frontal vitta broad, with a few fine hairs along front margin above upper margin of lunule. Lunule large, semicircular, rounded above. 1 strong reclinate ors on right side and 2 on left side. 6 long, incurved ori. Orbital hairs in 2 irregular rows, predominantly reclinate. Third antennal segment small, slightly longer than broad, rounded, microscopically pilose. Arista short, 2/3 vertical height of eye, only faintly pubescent, swollen at base. Eye large, bare, oval, slightly slanting. Facial keel narrow, slightly widening below. Mouth margin broadly rounded. Epistoma moderately broad, not extending upwards ( Figs1, 2 ). Cheek forming narrow ring below eye. Jowls deepest at rear, about 1/3 vertical height of eye. Peristomal margin almost straight, bearing 4–5 setulae. Vibrissa well developed. Palps short, moderately swollen at apex, with a pair of setae apically.

Mesonotum with 3-4+1 dc, greatly decreasing in size, first dc twice longer than fourth one. acr numerous, in 11–12 irregular rows. prsc well developed, about a half length of 1. dc. 1 strong ia, interalars setulae numerous, dense. ipa about twice shorter than opa. Basal scutellars as long as apical ones. Humerus with 1 long h, accompanying 1–2 setae which are about twice shorter than humeral bristle. Mid tibiae with 1–2 pd. Wing tip midway between veins R4+5 and M1+2 ( Fig. 3 ). Costa strongly extending to vein M1+2. Costal sections in proportion of 4.3: 1: 1. First cross-vein near midpoint of discal cell. Second cross-vein oblique. Last section of vein M3+4 1.5 times longer than penultimate. Wing length 4.3 mm. Ovipositor sheath about 1.5 times longer than 6th tergite.

Body largely brownish black. Hind margin of eye blackish brown. Frons, including orbits, brownish above level of lower ors, reddish-orange below. Lunule white-grey pruinose. Antennae yellowish, third antennal segment above brownish tinged; arista brownish. Cheeks and jowls predominantly yellowish. Face brown. Palps yellowish brown. Thorax dark brown, mesonotum grayish dusted. Legs entirely blackish-brown. Abdomen brownish black, moderately shining. Ovipositor sheath deep black, slightly shining. Wing hyaline, veins light brown. Halter yellow. Squamae whitish, margin and fringe light brownish.

Male unknown.

Host plant unknown.

Distribution. Tajikistan.

Type. Holotype, female, Tajikistan, Gissar ridge, valley of Varzob river, Kondara ravine, 1100 m, 24.06.1937 (leg. Gussakovsky).

Diagnosis. Large size, largely reddish orange frons, moderately broad epistoma and long last section of vein M3+4 are distinctive combination of characters of the new species in the Palaearctic fauna. There are some Nearctic Phytobia species [amelanchieris (Green), betulivora Spencer , pruinosa (Coquillett), setosa (Loew)] having at least partly light colored frons. In these species the shape of distiphallus is enough uniform. The distiphallus consists of a pair of long, slender, entirely separated from each other tubules. I propose to call these species as setosa -group after the oldest name. The new species very closely resembles Holarctic Phytobia betulivora Spencer (1969) which larva feeds on Betula nigra . Originally this species was described from the USA and Canada. Recently two males of P. betulivora were recorded from the Czech Republic (Č erny, 2001; Č erny, Vála, Barták, 2001). The unique distinctive external character of P. b e t u l i v o r a is conspicuous epistoma, extending upwards almost to base of antennae. Also one female reared ex Fraxinus from Ottawa resembles P. betulivora in the orange color of the frons, antennae and palps but the face and legs are black and the epistoma lacks the upwards extension ( Spencer, 1969: 105) but until now its species identity remains uncertain. Almost certainly that P. pseudobetulivora . belongs to the setosa -group and its distiphallus of the same type. Despite of the structure of male genitalia is not known I believe that P. betulivora Spencer and P. pseudobetulivora sp.n. are represent the separate species because the shape of epistoma is not subject of significant individual variation or sexual dimorphism.

Figures

FIGURES 1 – 3. Phytobia pseudobetulivora sp. n. 1 – 2, head: 1, front view, 2, lateral view; 3, wing.