Stegana (Steganina) silvestrella Zhang & Chen

WANG, YA-LIAN, LI, BING-XUE, CUI, MENG-DI, ZHANG, YUAN, WANG, LE, ZHANG, CAI-HONG, TSAUR, SHUN-CHERN, CHEN, HONG-WEI & HUANG, JIA, 2023, Revision of the subgenus Stegana (Steganina) from China, with assessment of species delimitation using DNA barcodes (Diptera, Drosophilidae), Zootaxa 5250 (1), pp. 1-109 : 96-98

Stegana (Steganina) silvestrella Zhang & Chen , sp. nov.

( Figs. 13G, 13H , 61 )

Diagnosis. This species is similar to S. (S.) flavipedes sp. nov. in the shape of male terminalia (Figs. 38, 61), but can be distinguished from the latter by having the pregonite blurry or absent ( Fig. 61C, D ); the aedeagus with numerous minute, serrated processes distally ( Fig. 61C, D ).

Description. Male and female: First flagellomere yellow. Clypeus yellow. Mesonotum brown medially, brownish yellow laterally ( Fig. 13G ). Katepisternum yellowish ( Fig. 13H ). Scutellum dark brown in male, brownish yellow in female, black near distal margin ( Fig. 13G ). Halter mostly yellowish ( Fig. 13H ). Fore femur with a row of 3 long setae on distal part of posteroventral surface. Abdominal tergites brown medially, yellow laterally ( Fig. 13G, H ); sternites yellow, about 1.8 times as wide as long. Male terminalia ( Fig. 61 ): Epandrium with ca. 9 setae on dorsal to posterior portions per side ( Fig. 61A ). Surstylus with some setulae near distal margin, lacking serrated processes and pubescence ( Fig. 61A, B ). Cercus with much pubescence ( Fig. 61A ). Hypandrium roundly expanded anteromedially ( Fig. 61C, D ). Aedeagus tubular, distally expanded and rounded, lacking pubescence ( Fig. 61C, D ). Aedeagal sheath lacking serrated process ( Fig. 61C, D ). Subepandrial sclerite slightly half-rounded ( Fig. 61G ).

Measurements and indices. BL = 2.63 mm in holotype (2.80–3.40 in 2♀ paratypes), ThL = 1.33 mm (1.33 in ♀), WL = 2.13 mm (2.00– 2.47 in ♀), WW = 1.00 mm (1.00– 1.13 in ♀), arb = 4/3 (4–5/3–4), avd = 1.00 (0.80–1.14), adf = 1.25 (1.00–1.40), flw = 2.42 (2.01–2.50), FW/HW = 0.45 (0.39–0.53), ch/o = 0.09 (0.08–0.11), prorb = 1.38 (0.83–1.33), rcorb = 0.75 (0.50–0.78), vb = 0.67 (0.60–0.80), dcl = 0.46 (0.46–0.48), presctl = 0.72 (0.70–0.82), sctl = 2.34 (2.11–2.50), sterno = 0.80 (0.60–1.11), orbito = 2.67 (2.12–2.67), dcp = 0.28 (0.25–0.28), sctlp = 1.86 (1.75–2.50), C = 1.67 (1.56–2.00), 4c = 1.29 (1.13–1.50), 4v = 1.91 (1.43–2.01), 5x = 2.43 (2.01–2.60), ac = 10.02 (9.00–12.01), M = 0.76 (0.73–0.84), C3F = 0.59 (0.64–0.87).

Type materials. Holotype ♂ ( SCAU, No. 125657, DNA #2752), CHINA: Wangtianshu , Mengla, Yunnan, 21°36'09''N, 101°35'06''E, alt. 700m, 25.iv.2007, ex tree trunk, H.W. Chen. Paratypes: 2♀ ( SCAU, Nos. 125658, 59, DNA #2562), Mengdong , Cangyuan, Yunnan, 23°10'08''N, 99°13'52''E, alt. 1320m, 10.v.2016, ex tree trunks, J. Huang, Y.L. Wang.

Distribution. China (Yunnan).

Etymology. From the Latin word " silvestris " (= arboreal), referring to the arboreal Steganina flies.

Figures

FIGURE 13. Head, thorax, and abdomen in dorsal and lateral views: A, B. Stegana (Steganina) rava Cui & Chen, sp. nov.; C, D. S. (S.) sciophila Li & Chen, sp. nov.; E, F. S. (S.) septencolorata Li & Chen, sp. nov.; G, H. S. (S.) silvestrella Zhang & Chen, sp. nov.; I, J. S. (S.) simola Cui & Chen, sp. nov.

FIGURE 61. Stegana (Steganina) silvestrella Zhang & Chen, sp. nov., male terminalia. A. Epandrium, surstylus, and cercus in lateral view; B. Surstylus in ventral view; C, D. Hypandrium, aedeagus, and phallapodeme in ventral and lateral views; E, F. Aedeagal sheath in ventral and lateral views; G. Subepandrial sclerite in ventral view.