Pseudostegana nannanae, Gong & Chen, 2018

Gong, Lu & Chen, Hongwei, 2018, Seven new species of the genus Pseudostegana (Diptera: Drosophilidae) from South-west China, with DNA barcoding information, Journal of Natural History 52 (31 - 32), pp. 2097-2119 : 2107-2109

Pseudostegana nannanae sp. nov.

( Figures 3 (g–l) and 7)

Diagnosis

This species strongly resembles P. acutifoliolata Li, Gao and Chen, 2010 from Hainan, China, in the wing pattern ( Figure 3 (i)) and male terminalia ( Figure 7), but can be distinguished from it by the ocellar triangle, scutum and aedeagus; in this species, ocellar triangle brownish yellow, narrowly elongated to anterior margin of frons (Figurer 3(j)); scutum nearly yellow ( Figure 3 (h,k)); aedeagus medially expanded in ventral view ( Figure 7 (b)). The interspecific genetic distance to P. acutifoliolata is 9.2%, but to P. bifasciata Chen and Wang in Chen et al. (2005) 9.0% is the smallest within this group; there are 10 diagnostic sites between P. nannanae sp. nov. and P. acutifoliolata , and 11 diagnostic sites between P. nannanae sp. nov. and P. bifasciata ( Figure 2).

Description

Male and female. Head ( Figure 3 (g,j)): Ocellar triangle brown, narrowly elongated to anterior margin of frons. Frons brown. Pedicel and first flagellomere yellow. Face yellow. Clypeus brown. Palpus yellow, broad, large, medially half as wide as long in male. Gena brown. Thorax ( Figure 3 (h,k)): Scutum nearly yellow. Pleura yellow anteriorly, brown black posteriorly. Katepisternal setae three. Scutellum brownish, yellow anterior and posterior margins. Legs: Yellow, dark on knee joints of mid- and hind legs. Abdomen ( Figure 3 (l)): First and second tergites nearly yellow, narrowly dark brown along posterior margin; third tergite anteriorly yellow and with brown medial stripe posteriorly; the rest dark brown. Sternites yellow on second and third, brown to dark on fourth to sixth. Male terminalia ( Figure 7): Epandrium slightly protruding on ventral margin, with about 14 setae per side. Surstylus protruding on posteroventral corner. Cercus ventrally protruding, dorsally elongated. Paramere subapically with one small acute projection, dorsomedially triangularly protruding in lateral view, with two long sensilla on expanded lobe and several sensilla on dorsomedial projection. Aedeagus apically strongly curved dorsad, dorsomedially expanded in lateral view, with several thin finger-like projections on basal process.

Measurements

BL = 3.06 mm in holotype (range in two female paratypes: 3.13–3.33), ThL = 1.27 mm (1.20–1.40), WL = 2.47 mm (2.67–3.23), WW = 1.23 mm (1.23), arb = 7/1 (6–7/1), avd = 1.09 (0.85–1.00), adf = 1.83 (1.67–2.33), flw = 2.16 (1.44–1.80), FW/HW = 0.44 (0.43–0.44), ch/o = 0.03 (0.05–0.08), prorb = 0.85 (0.71–0.94), rcorb = 0.16 (damaged), vb = 1.00 (0.73–0.91), dcl = 0.25 (0.21), sct1 = 0.81 (0.97), sterno = 0.77 (0.43–0.60), orbito = 0.69 (0.55–0.56), dcp = 0.13 (0.12–0.13), sct1p = 1.08 (1.00–1.17), C = 2.20 (1.91– 1.96), 4c = 1.43 (1.381.48), 4v = 3 (2.63–2.77), 5x = 1.00 (1.00–1.18), ac = 8.75 (11.50– 12.33), M = 0.60 (0.60–0.65), C3F = 0.81 (0.77–0.85).

Type material

Holotype male ( SCAU, No. 111413), China: Dafengding, Mabian , Sichuan, 28.694°N, 103.364°E, altitude 1500 m, 28 June 2017, ex tussock, L. Gong . Paratypes: two females ( SCAU, Nos. 111414–15), N .N. Wang, same data as holotype .

Etymology

Patronym of the collector Ms Nannan Wang (SCAU).

Distribution

China (Sichuan).