Stichillus spinosus Liu & Chou 1996
Creators: name: Lee, Jun-Ho
name: Kim, Sam-Kyu
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Phoridae
Stichillus
Stichillus spinosus

description: Stichillus spinosus Liu & Chou, 1996
(Figs. 1G, 1H, 2G, 2H, 3D–F, 4D, 5G, 5H, 9)
Stichillus spinosus Liu & Chou, 1996: 44. Type locality: Sichuan, China.
Diagnosis. This species can be distinguished from other Stichillus species by the combination of the following characteristics: hind tibia with three dorsal longitudinal setal palisades basally, middle setal palisade fused with anterior palisade at middle to apical one-third; male epandrial lobe small, rounded; inner projection on posterior margin of hypandrium long, apically blunt; dorsal plate of aedeagus gently curved upwardly, without pointed dorsal process, spinulose on right surface of apical portion; ventral membrane of aedeagus extremely long; female tergite 9 short, oval, with deep longitudinal incision anteromedially.
Description. Male. Body length 2.69–3.22 mm (n=10). Head (Figs. 1G, 2G, 3D–F). Frons black, shiny, with three transverse rows of four long bristles and sparsely covered fine hairs; supra-antennal bristle absent; middle row of bristles slightly procurved. Ocellar region as in figures 2G, 3D–F. First flagellomere brown to orange, oval, 1.6× longer than wide, apically pointed; arista brown, located subapically. Palpus yellowish brown, with single long bristle on apex and some shorter bristles on near apex to ventral margin. Labrum and labella yellow, short. Thorax (Fig. 1G) Scutum and scutellum black. Posterior margin of scutum with two pairs of strong prescutellar bristles; inner pair of bristles distantly spaced with each other. Scutellum with anterior pair of long, narrow bristles and posterior pair of strong bristles distinctly longer than anterior bristles. Pleuron dark brown; upper half of anepisternum covered with short setae. Legs (Figs. 1G, 4D). Blackish brown except fore femur dark brown basally and gradually brighter apically, fore tibia and fore tarsus yellowish brown, midtarsus brown. Fore tibia with one strong dorsal bristle on basal half and single longitudinal row of short dorsal setulae on apical half. Fore tarsomere 5 widened, with enlarged pulvilli. Midtibia with two dorsal longitudinal setal palisades on basal half, which fused together from middle to apical half, and with one pair of bristles on basal quarter (one dorsal and the other anterodorsal), one long anteroventral preapical bristle, two short dorsal preapical setae, and one long posteroventral apical spur. Hind tibia (Fig. 4D) with three dorsal longitudinal setal palisades basally, middle setal palisade fused with anterior palisade at middle to apical one-third, and with one anterodorsal strong bristle on basal third, one anterodorsal preapical bristle, one dorsal and three ventral long apical spurs, and some posterior—posteroventral apical short setae. Wing (Fig. 5G). 2.5–3.06 mm long (n=10). Costal index 0.49–0.54. Mean costal ratio 1:1; range 0.91–1.09:1. Costal setae of costal section II 0.06–0.11mm long. Vein Rs with single row of short, fine hairs on dorsal face except apical end. Vein R 2+3 absent. Vein M 1 slightly curved basally and nearly straight apically. Veins brown, membrane hyaline with yellow tinge. 5–8 alular setae present, 0.16–0.21 mm long. Halter black. Abdomen (Fig. 1G). Tergites black, shiny, extended posteromedially; tergite 2 elongated, approximately twice longer than tergite 1. Venter of abdomen grayish brown, sternite 6 not developed. Hypopygium (Fig. 9A–C). Epandrium nearly symmetrical, dark brown; epandrial lobe small, rounded, covered with some long hairs apically. Hypandrium large, dark brown; lateral membranous lobe nearly triangular, closely situated to posteroventral margin of hypandrium, densely spinulose; inner projection on posterior margin of hypandrium long, with blunt tip, protruded posteroventrally (Fig. 9B); tip of inner projection situated far above bottom level of lateral membranous lobe. Cercus and hypoproct short, with some short hairs. Aedeagus (Fig. 9D, E). Dorsal plate yellowish brown except basal portion dark brown, gently curved nearly perpendicularly, without pointed dorsal process and arm on right side of basal portion, spinulose on right side of apical portion (Fig. 9E). Ventral membrane narrow, remarkably elongated, hyaline, approximately 5× as long as maximum width of basal portion, tapering apically, rounded.
Female. Body length 3.28–4.14 mm (n=3). Head (Figs. 1H, 2H). Similar to male, except first flagellomere smaller, globose, orange to yellow. Ocellar region as in figure 2H. Thorax (Fig. 1H). Similar to male. Legs (Fig. 1H). Similar to male, except fore apical tarsomere not widened, pulvilli not enlarged. Wing (Fig. 5H). Similar to male, 3.41–3.52 mm long (n=3). Costal index 0.5–0.53. Mean costal ratio 0.98:1; range 0.94–1.04:1. Costal setae of costal section II 0.08–0.1 mm long. 7–9 alular setae present, 0.15–0.23 mm long. Halter black. Abdomen (Figs. 1H, 9F, G). Tergites 1–6 well developed, black. Tergite 2 elongated as male. Tergite 7 absent (Fig. 9F, G). Tergite 8 (Fig. 9G) rectangular, dark brown, twice longer than wide. Tergite 9 (Fig. 9F, G) short, ovate, approximately 1.5× as long as maximum width, yellowish brown, with deep longitudinal incision anteromedially; each lateral margin and posterior margin with one pair of long hairs. Venter of abdomen grayish brown, with only sternite 9 discernable. Genital opening not distinctly enlarged posteriorly (Fig. 9F). Cercus oval, divergent from each other, apically with two long and some short hairs.
Specimens examined. Korea: 6♂, Gyeongsangnam-do, Jinju-si, Ibanseong-myeon, Daecheon-ri, Gyeongsangnamdo Arboretum, 35°09′39.7″N, 128°17′41.3″E, 43 m, 1–15.ix.2014, Malaise trap, J. H. Hwang leg. (KNU); 1♂, ditto, 16–31.viii.2015; 1♂, Seoul, Gwanak-gu, Sillim-dong, forest in Seoul National University, 37°27′20.7″N, 126°56′57″E, ca. 97 m, 26.viii–2.ix.2019, Malaise trap, Nam & Park leg. (KNU); 4♂ 2♀, Jeollanam-do, Gwangyang-si, Ongnyong-myeon, Chusan-ri, Southern Experimental Forest of Seoul National University in Mt. Baegunsan, 35°01′52.9″N, 127°36′24.8″E, ca. 97 m, 10–24.ix.2019, Malaise trap, Nam & Park leg. (KNU); 2♂ 1♀, Gangwon-do, Jeongseon-gun, Imgye-myeon, Gamok-ri, Baekbongnyeong Peak, 37°32′32.4″N, 128°57′50.1″E, 780 m, 5.ix.2020, hand collecting, J. H. Lee leg. (KNU); 1♂, ditto (NIBR).
Ecology. This species was collected widely in mountainous regions in South Korea. Altitudinal distribution of the species seemed relatively lower than those of S. japonicus and S. koreanus sp. nov., about under 800 m above sea level. Adults can be found on leaves of shrubs in shaded forest. Detailed ecological information including larval feeding habits is largely unknown.
Remarks. The dorsal plate of aedeagus of Korean specimens is curved nearly perpendicularly, as same with the Chinese specimens illustrated in original description (Liu & Chou 1996), while that of Japanese specimens is not perpendicularly curved (see Nakayama & Shima 2004: fig. 5C, D). This might reflect some degree of geographical variation or just simply a difference in viewing angles.
Distributions. Korea (Seoul, Gangwon-do, Jeollanam-do, Gyeongsangnam-do), China, Japan.
description: Published as part of Lee, Jun-Ho & Kim, Sam-Kyu, 2023, A taxonomic study on the genus Stichillus (Diptera: Phoridae) from South Korea, with a key to species from East Asia, pp. 381-398 in Zootaxa 5352 (3) on pages 392-395, DOI: 10.11646/zootaxa.5352.3.3, http://zenodo.org/record/8407390