Hydrotaea hsiai Fan, 1965

Vikhrev, Nikita E. & Sorokina, Vera S., 2017, Taxonomic notes and faunistic data on the Muscidae (Diptera) of the Altai Mountains (Russia), Zootaxa 4311 (2), pp. 241-254 : 247-248

Hydrotaea hsiai Fan, 1965

Fig. 1 C–F

Hydrotaea hsiai Fan, 1965: 87 . Type locality: China, Qinghai prov., Haiyan distr. (= 37.0°N 100.8°E).

Descriptive notes: MALE ( Fig. 1 D), body length 4.5–5.5 mm.

Head: Eyes bare. Fronto-orbital plates touching, distance between eyes equal to diameter of anterior ocellus. Fronto-orbital plates glossy black in anterior half. Fronto-orbital plates with 8–9 pairs short inclinate setae from lunula to middle of frons. Antenna black, arista virtually bare.

Thorax: Glossy black, without any dusting. Chaetotaxy: strong ac absent, ac hairs long, in 6 rows; 2+4 dc; katepisternals 1+1, katepimeron bare; notopleuron with hairs on area between notopleural setae. Lower katepisternum ahead of mid coxa with usual setae reduced, but with a pair of clusters of 3 long slightly back-curved setae.

Wing: Hyaline, calypters white, haltere with black knob.

Legs: Black; f1 with two typical ventral hooks at apex; t1 with pd seta in apical 1/4; f2 with about 10 strong and long pv setae (1.5– 2x as long as femur width), 5 more sparsely placed setae in basal half and a cluster of 5 more approximated setae in apical half, medially with a bare gap between the two clusters of setae; on av- surface with 5– 7 weaker setae in apical half; t2 with 2 p and elongated hairs on p surface; f3 with 4–5 long av in apical 1/3; t3 with 2 av, 1 short ad and 1 pd. Mid tarsus modified: tar2– 1 in basal half ventrally with a cluster of 4–5 elongated spinulose setulae and 6–7 fine curved hairs.

Abdomen: Entirely glossy black with blue shine.

FEMALE ( Fig. 1 C) differs from male as follows: body length 4.5–5.0 mm; frons wide, frontal triangle glossy black, reaching middle of frons; fronto-orbital plates and upper parafacials glossy black; 3+3 elongated setae on lower katepisternum distinct, but weaker and shorter than in male; f1 without hooks at apex; f2 with only short setulae; t2 without elongated hairs on p surface; mid tarsus not modified.

Remarks. Hydrotaea hsiai Fan, 1965 was described long ago in Chinese ( Fan, 1965) and the identity of this species has been unclear. The information given on Hydrotaea hsiai in Xue, Wang & Du (2007) and Xue, Wang & Wang (2007) is fragmentary, contradictory and with errors. However, the combination of two uncommon characters (shining black body, with both thorax and abdomen without pollinosity, and modified tar2–1, with a tuft of setulae in subbasal part) convinces us that the specimens listed above belong to Hydrotaea hsiai . Hydrotaea hsiai is closely related to Hydrotaea tuberculata Rondani, 1866 .

Both species share the following characters: the presence on lower katepisternum of a set of 3 strong and long (about as long as fore coxa length) setae; modified tar2–1 with a tuft of setulae (in basal or apical part respectively); t2 with 2 pd setae and a row of fine p setulae, without ad; t3 with 1–2 av, 1 short ad and 1 pd.

These species differ as follows (males):

- Thorax and abdomen shining (greenish) black, without any pollinosity. In basal half tar2–1 ventrally with a cluster of 4–5 elongated spinulose setulae and 6–7 fine curved hairs ( Fig. 1 F). f2 with about 10 strong and long pv setae (1.5– 2x as long as femur width), 5 more sparsely placed setae in basal half and a cluster of 5 more approximated setae in apical half, medially with a bare gap between the two clusters of setae. t2 without elongated setulae on a -surface.................... hsiai Fan

- Scutum matt black, abdomen with thin but distinct grey dusting and a black median vitta. In apical half tar2–1 ventrally with a cluster of 4–5 elongated spinulose setulae, without curved hairs ( Fig. 1 E). f2 on pv -surface with a sparse row of 6–8 rather fine setae. t2 on a -surface in apical 2/3 with a row of elongated setulae............................... tuberculata Rondani

The female of Hydrotaea hsiai may also be reliably distinguished by the following set of characters: thorax and abdomen shining (greenish) black, without any pollinosity; fronto-orbital plate and upper paracial shining black; lower katepisternum with a set of 3 approximated medium strong setae, otherwise bare; t2 with 2 pd; t3 with 2 av, 1 short ad and 1 pd.

Figures

FIGURE 1. A. Xestomyia atrox (female). B. Phaonia fusca (female, lectotype of suspiciosa Stein). C, D, F. Hydrotaea hsiai: C. Female. D. Male. F. Male mid tarsomere 1. E. Hydrotaea tuberculata, male mid tarsomere 1. G. Thricops aduncus, male hind tibia.