Hirtodrosophila lambda Chen, Katoh & Gao, 2019

Chen, Yu, Katoh, Takehiro K. & Gao, Jian-Jun, 2019, The Hirtodrosophila melanderi species group (Diptera: Drosophilidae) from the Huanglong National Nature Reserve, Sichuan, China, Zootaxa 4623 (1), pp. 113-131 : 120-121

Hirtodrosophila lambda Chen, Katoh & Gao , sp. nov.

( Figs 2 E–H, 4G–L, 7)

Diagnosis. Cercus caudoventrally narrow and elongated anteriad in ventral view, with ca. three black, stout, peglike spines, lacking a patch of short, thick spines ( Fig. 7D ). Fork of aedeagus with branches pointed apically and broadened basally, and finely serrate on apex to lateral margin ( Fig. 7 I–K, M).

Description (characters commonly seen in H. minshanensis sp. nov. not repeated) (♂). Head ( Figs 2E, F , 4 G– L) nearly entirely blackish brown, except for red eyes. Frontal vitta and fronto-orbital plate posteriorly paler. Ocellar triangle brown along margin of triangle made by ocelli. Arista with 4–5 dorsal branches. Supracervical setae 12–13 per side; postocular setae ca. 37 per side. Cibarium with 6–7medial and ca. 19 posterior sensilla per side. Prementum with five (one proximal, two lateral, and two distal) pairs of setae. Labellum with seven pseudotracheae per side.

Thorax ( Fig. 2E, F ): Postpronotal lobe dark brown, ventrally paler, with ca. three prominent setae, middle one longer.

Legs ( Fig. 2E ) yellowish brown to dark grayish brown; foreleg darker in color than others. First tarsomeres of all legs shorter than total length of four succeeding tarsomeres.

Male terminalia ( Fig. 7 ): Epandrium with ca. 25 long setae per side. Cercus ventrally concaved in posterior view, with ca. 44 setae including ventral thick ones. Surstylus with upper and lower, straight rows of ca. eight prensisetae in each; inner surface with ca. 27 setae, dorsal ones longer and trichoid-like, ventral ones shorter and thicker. Tenth sternite anteriorly broadened, anteromedially notched. Paramere with ca. three sensilla slightly shorter than paramedian setae.

Measurements (in mm): BL = 2.43 in holotype (in 1♂ paratype: 2.45), ThL = 1.25 (1.20), WL = 3.24 (3.22), WW = 1.38 (1.30).

Indices: FW/HW = 0.53 (in 1♂ paratype: 0.51), ch/o = 0.26 (0.32), prorb = 0.81 (0.70), rcorb = 0.44 (0.35), vb = 0.35 (0.50), orbito = 0.67 (0.82), dcl = 0.54 (0.54), sctl = 1.11 (1.03), sterno = 0.68 (0.69), dcp = 0.53 (0.59), sctlp = 1.44 (1.33), C = 3.04 (3.19), 4c = 0.67 (0.64), 4v = 1.35 (1.32), 5x = 1.55 (1.36), ac = 2.55 (2.84), M = 0.41 (0.36), C3F = 0.48 (0.50).

Holotype. ♂ (#06453), CHINA: Huanglong scenic area, Huanglong Nature Reserve, Ngawa , Sichuan, 32°45'07" N, 103°49'18" E, 3,200 m, 13−14.xi.2018, by net sweeping, J.J. Gao.

Paratype. CHINA: 1♂ (#06455), same data as holotype .

Distribution. China (Sichuan).

Etymology. Referring to the bifurcated, lambda-shaped tenth sternite.

Remarks. This species resembles H. seticlasper Katoh & Gao, 2018 , H. spinicerca Katoh & Gao , and foregoing new species H. minshanensis , but can clearly be distinguished from them by cercus narrowly elongated with three distinctly long spines, and lacking a patch of short spines.

Figures

FIGURE 2. Left lateral habitus, head and thorax (dorsal view), wing (left ventral or right dorsal view), and abdomen (dorsal view). A−D, H. minshanensis sp. nov. (holotype #06466); E−H, H. lambda sp. nov. (holotype #06453). Scale bar (dashed) = 0.5 mm (the same in the following figures).

FIGURE 4. Head (anterior view), postocciput (posterior view), cibarium (dorsal and lateral view), and prementum (ventral and lateral view). A−F, H. minshanensis sp. nov. (paratype #06449); G−L, H. lambda sp. nov. (paratype #06455). Abbreviations: cly = clypeus, m s = medial sensilla, p s = posterior sensilla, spc s = supracervical setae. Scale bar (solid) = 0.1 mm (the same in the following figures).

FIGURE 7. Hirtodrosophila lambda sp. nov. (holotype #06453). A, B, periphallic organs (posterior and posterolateral view, respectively); C, ventral lobe of epandrium (lateral view); D, cerci (ventral view); E, dorsal part of surstylus (posterolateral view); F, inner surface of surstylus (posterolateral view); G, H, 10th sternite (anterior and ventral view, respectively); I−K, phallic organs (ventral, ventrolateral, and lateral view, respectively); L, sensilla of paramere (ventrolateral view); M, fork of aedeagus (ventral view).