Pseudacteon robustisetosus, Liu & Disney, 2022

Liu, Guang-Chun & Disney, R. Henry L., 2022, Revision of the ant-parasitizing genus Pseudacteon Coquillett (Diptera, Phoridae) from China, Zootaxa 5138 (3), pp. 201-237 : 205

2. Pseudacteon robustisetosus sp. nov.

( Figs. 2A–F )

Diagnosis. Female. Apical seta longer than maximum width of palpus; fore tarsomere 5 longer than tarsomere 1; setal palisade 2/3 length of mid tibia; setulae below basal half of hind femur shorter than those of anteroventral row of outer half; tergite VI reduced to a narrow anterior strip in middle but each lateral quarter with 2 long and 2 shorter setulae; sternite VI clearly defined, with 4 very strong pin-shaped setae and some long setulae; dorsum of oviscape with 3–4 short setulae on sub-apex of each side; venter of oviscape with 10–14 fine, long and transversely-inclined setulae arranged in two longitudinal rows.

Female. Frons ( Fig. 2A ) brown, with 14–16 setulae. Upper supra-antennal setae shorter and thinner than other frontal setae. Lower interfrontal seta directly under lower fronto-orbital seta. Second row of frontal setae clearly concave, with upper interfronal setae further from each other than either is from upper fronto-orbital seta. Flagellomere 1 brown and subglobose. Palpus pale brown, with 6 long setae, apical one longer than maximum width of palpus. Labrum and labella pale yellow.

Thorax brown. Scutellum with two pairs of setae, posterior twice length of anterior. Legs brown and fore leg being paler. Ratios of lengths of fore tarsomeres about 1.14: 0.91: 0.70: 0.70: 1, with all five bearing a setal palisade ( Fig. 2C ). Setal palisade extends 2/3 length of mid tibia ( Fig. 2D ). Setae below basal half of hind femur a little shorter than those of anteroventral setulae of outer half ( Fig. 2E ). Wing ( Fig. 2B ) length 1.58 mm, width 0.79 mm, width/length 0.50. Costal index 0.39–0.40. Costal ratios 1.53: 1, second section with 5 dorsal setulae. Costal cilia 0.077–0.078 mm long. Costa with 17–18 dorsal setulae. Alula with 3 setae. Veins brown, membrane brownish gray. Haltere brown.

Abdominal tergites yellow and tergites 1–5 with sparse minute setulae on posterior margins. Tergite VI reduced to a narrow anterior strip in middle but each lateral quarter bears 2 long and 2 short setulae at rear margin. Venter brown. Sternite VI clearly defined, with 4 very strong, pin-shaped setae and some long setulae. Oviscape brown. The dorsum of the oviscape arched, with 3–4 short setulae on sub-apex of each side. The venter of the oviscape with 10–14 fine, long and transversely-inclined setulae arranged in two longitudinal rows ( Fig. 2F ).

Male. unknown.

Distribution. China (Sichuan, Xizang).

Etymology. The species epithet refers to the characters of pin-shaped setae on sternite VI.

Material examined. Holotype, ♀ (slide), China, Xizang, Motuo (29°25′14″N, 95°25′23.3″E; 3200m), 3–Aug– 2013, Jianfeng Wang . Paratype, 1♀, China, Sichuan, Mt. Wanglang (33°58′11.9″N, 104°06′7.19″E, 2800m), 24– Jul–2017, Lixin Su .

Remarks. The new species is similar to P. quadrisetalis Liu et Cai, 2013 , it differs from the latter by the upper supra-antennal setae shorter and thinner than other frontal setae, fore tarsomere 5 shorter than tarsomere 1, second section of wing vein costa shorter and the pin-shaped setae on sternite VI longer and thinner.

Figures

FIGURES 2A–F. Pseudacteon robustisetosus sp. nov., female. A. head, anterior view; B. wing, dorsal view; C. fore tarsus, anterior view; D. mid tibia, anterior view; E. hind femur, anterior view; F. ovipositor, ventral view. Scale bar = 0.1mm.