Eutrichosomella yunnanensis, Chen & Chen, 2021

Chen, Ye & Chen, Hai-feng, 2021, First report of Eutrichosomella Girault (Hymenoptera, Aphelinidae) from China, with description of a new species, ZooKeys 1071, pp. 1-9 : 1

Eutrichosomella yunnanensis sp. nov.

Figs 1 , 5-11 , 12-15

Type material.

Holotype: China • 1♀; Yunnan Province; Xishuangbanna; Mengla County; Menglun Town; 21°53.72'N, 101°17.08'E; 611m a.s.l.; 22 Aug. 2020; Y. Chen, H.-f. Zhao, Y.-g. Qin, Z.-g. Chen, leg.; LFNU A-Eut202101 [on slide]. Paratypes: 1♂; same data as holotype; LFNU A-Eut202102 [on slide]. 1♀; Yunnan Province; Xishuangbanna; Mengla County; Menglun Town; 21°54.28'N, 101°16.75'E; 629m a.s.l.; 25 Jun. 2019; Z.-l. Bai, Z.-g. Chen, Y.-j. Lin, C. Wang, Y.-f. Tong, H. Yu leg.; LFNU A-Eut202103 [on slide]. 1♀; Yunnan Province; Xishuangbanna; Mengla County; Menglun Town; 21°54'N, 101°16.9'E; 561m a.s.l.; 27 Jun. 2019; Z.-l. Bai, Z.-g. Chen, C. Wang, Y.-f. Tong, H. Yu leg.; LFNU A-Eut202104 [on slide].

Diagnosis.

Females of Eutrichosomella yunnanensis sp. nov. can be distinguished from females of other species in this genus by the following combination of characters: dark brown gaster; characteristically pigmented forewing as in Figs 2 , 8 ; long pedicel and F3 as in Fig. 6 ; linea calva broadening from the anterior forewing margin to the posterior forewing margin; long postmarginal vein, almost as long as the stigma vein (Fig. 8 , inset) and location of setae on mesoscutellum as in Fig. 7 .

Description.

Female. Body length 1.18-1.63 mm (1.48 mm).

Coloration (Figs 1 , 2 ). Head with face and malar space pale, vertex orange yellow and with dark setae, occiput pale. Eyes yellow, ocelli dark brown. Antenna with scape pale yellow and with ventral surface brown, pedicel pale brown to brown, funicle brown, clava with basal half to two thirds brown and remainder parts yellow. Mandible pale with apex dark. Pronotum yellow. Mesosoma mostly orange yellow, with lateral lobe of mesoscutum paler; propodeum with two brown patches interior to each spiracle. Mesopleuron pale. Forewing (Fig. 8 ) largely infuscated, with hyaline parts as follows: submarginal vein, a curved band adjacent to stigmal vein and apex narrowly. Hindwing (Fig. 9 ) infuscated medially and apically. Legs generally yellow and suffused with brown on tibiae and tarsomeres. Metasoma with petiole pale yellow, gaster mostly dark brown and with blue reflections, Gt1 and third valvula brown yellow.

Head (Fig. 5 ), in frontal view, scaly reticulated, with the reticulation becoming elongate laterally. Frontovertex 0.3 × head width, vertex with about 30 brown setae. Ocellar triangle with apical angle acute. Mandible with two teeth and a truncation. Antenna (Fig. 6 ) with scape 4.3-4.6 × (4.5 ×) as long as wide; pedicel 3.2-3.6 × (3.6 ×) as long as wide, about as long as funicle segments combined; an anellus (Fig. 6 , inset) is present between pedicel and F1; F1 transverse, with ventral margin a little longer than dorsal margin, 0.7-0.9 × (0.9 ×) as long as wide; F2 quadrate, 1.2 × as long as F1; F3 1.5-1.8 × (1.8 ×) as long as wide, 1.3 × as long as F1 and F2 combined; clava 3.0-3.7 × (3.7 ×) as long as wide, 0.8 × length of scape, and 2.5-2.6 × (2.6 ×) as long as F3. F3 and clava with 4 and 16 longitudinal sensilla, respectively. Measurements of holotype, length (width): scape, 320.9 (70.7); pedicel, 171.4 (47.6); F1, 37.0 (42.0); F2, 42.8 (42.8); F3 101.7 (57.3); clava, 256.4 (69.7).

Mesosoma (Fig. 7 ). Dorsum of mesoscutum polygonal reticulate, with the sculpture of lateral lobe of mesoscutum elongate on inner side; mesoscutellum mostly reticulate, smooth posteriorly, and with a pale longitudinal groove medially; metanotum reticulate on median region; propodeum smooth, but with finely polygonal reticulate sculpture on lateral sides. Pronotum with 4-5 rows of setae, the row along the posterior margin longer. Midlobe of mesoscutum 0.8 × as long as wide, with 21-24 (24) setae, the seta on the anterolateral corner and the apical pair of setae long. Lateral lobe of mesoscutum with 3 or 4 setae. Axilla with 1 long seta, its width 1.3 × anterior width of mesoscutellum. Mesoscutellum hexagonal, as long as wide, with two pairs of long setae located in anterior part and posterior part, respectively. Distance between anterior pair of scutellar setae 0.4 × that between posterior pair. Placoid sensilla located in median region of mesoscutellum; distance between sensilla 0.5 × that between posterior scutellar setae. Metanotum 0.7 × as long as propodeum in median length. Propodeum with 13-15 (15) short setae (Fig. 7 ) proximal to spiracle, and with a digital projection on median area posteriorly.

Wings. Forewing (Fig. 8 ) 2.8 × as long as wide. Costal cell 0.8 × length of marginal vein, with 12 fine setae; submarginal vein with 5 setae; parastigma with 1 seta; marginal vein with 14 setae along anterior margin; postmarginal vein long, about as long as stigmal vein; stigmal vein swollen posteriorly and with 3 big and 1 small sensilla arranged nearly in a line (Fig. 8 , inset). Linea calva becoming broader posteriorly, not closed. Hindwing (Fig. 9 ) 4.2 × as long as wide, with longest marginal fringe 0.2-0.3 × (0.3 ×) wing width. Measurements of holotype, length (width): forewing, 1441.6 (529.4); costal cell, 350; marginal vein, 460; postmarginal vein, 40; stigmal vein, 40; hindwing 1189.7 (282.4).

Legs (Fig. 10 ). Mesotibial spur 0.7 × as long as corresponding basitarsus. Length measurements of holotype: mesotibia, 564.4; mesotibial spur, 147.1; mesobasitarsus, 216.

Metasoma (Fig. 11 ). Dorsum of metasoma generally smooth, except median area of Gt1 and lateral sides of gasteral tergites with fine reticulations. Ovipositor originating from Gt2 to apex of Gt3, 0.8-0.9 × (0.8 ×) as long as mesotibia and slightly exerted. Second valvifer 2.7 × as long as third valvula; third valvula 0.6 × as long as mesobasitarsus. Length measurements of holotype: ovipositor, 465.2; second valvifer, 340.7; third valvula, 124.5.

Male. Body length 1.16 mm. Similar to female except as follows. Forewing (Figs 4 , 14 ) with the infuscate patches a little paler than in the female. Legs paler. Gaster (Fig. 3 ) with Gt1 and Gt2 yellow, Gt3 mostly yellow and with a transverse short brown band on each lateral side, Gt4 brown posteriorly, Gt5-Gt7 brown.

Head with ocellar triangle with apical angle obtuse. Antenna (Fig. 12 ) with scape expanded ventrally, 3.4 × as long as wide; F1 and F2 subequal in length and width, F3 about as long as F1 and F2 combined. F3 and clava with 2 and 7 longitudinal sensilla, respectively. Genitalia (Fig. 15 ) with paramere 1.8 × as long as wide; each digitus 0.3 × length of paramere, with two short denticles and a fine seta at apex; aedeagus 1.5 × as long as paramere and 1.2 × as long as mesobasitarsus. Measurements, length (width): scape, 230.7 (67); pedicel, 122.1 (37); F1, 28.5 (30.5); F2, 31 (31); F3, 57.5 (42.3); clava, 149 (50); forewing 1185.2 (426.7); hindwing 1010 (210); mesotibia, 431.3; mesotibial spur, 96.9; mesobasitarsus, 168.6; genitalia, 245.3; paramere, 132.5; aedeagus, 198.8.

Host.

Unknown.

Etymology.

Named after the locality of type specimen.

Distribution.

China (Xishuangbanna Dai Autonomous Prefecture of Yunnan Province).

Comments.

This species does not run to any couplet in the key to Indian species of Eutrichosomella (Hayat & Veenakumari 2016), and differs from the four Indian species ( E. ibra , E. indica , E. keralaensis , and E. veenakumariae ) by the following combination of characters: antenna mostly brown with scape and apical of clava pale yellow to yellow (vs. antenna white to yellow, or antenna dark brown with a subapical band on scape and most of clava white; cf. fig. 3 in Manickavasagam and Menakadevi 2012), F3 1.5-1.8 × as long as wide (vs. less than 1.4 × as long as wide), forewing largely infuscated, with the following parts hyaline: the area below the submarginal vein, a curved band adjacent to the stigmal vein and apex narrowly (vs. forewing with broad or narrow infuscation below margin vein, without hyaline band adjacent to stigmal vein; forewing of E. keralaensis similar to the new species but with a large suboval hyaline spot in the median infuscate area; cf. fig. 6 in Manickavasagam and Menakadevi 2012), postmarginal vein of forewing long, about as long as stigmal vein (vs. absent, or three-fourths of stigmal vein), two pairs of setae on mesoscutellum located in anterior part and posterior part, respectively (vs. both located in posterior part; cf. fig. 4 in Hayat 2014, except E. keralaensis ). Apart from the above differences, the new species can be distinguished from E. keralaensis by having scape 4.3-4.6 × as long as wide (vs 3.1 ×), F1 a little wider than long and F2 quadrate (vs. F1 and F2 both 0.5 × as long as wide), and propodeum with 13-15 setae proximal to spiracle (vs. at least 3, possibly 4, setae according to redescription of Hayat 2014).

Eutrichosomella yunnanensis sp. nov. seems morphologically close to E. albiclava . Based on Girault’s description and images (QMDIU_03328-QMDIU_03335 from the Queensland Museum), E. yunnanensis differs from E. albiclava by following characters: color of gaster apparently darker than mesosoma in slide-mounted specimen (vs. nearly the same according to QMDIU_03330 and QMDIU_03331), pedicel about as long as funicle segments combined (vs. two thirds), F3 1.5-1.8 × as long as wide (vs. a little longer than wide), forewing infuscated below marginal vein and subapically (vs. only infuscated below marginal vein, without any distal pigmentation, cf. QMDIU_03332).

Figures

Figure 1 - 4. Eutrichosomella yunnanensis sp. nov., paratypes 1 body (♀), dorsal view 2 body (♀), lateral view 3 body (♂), dorsal view 4 body (♂), lateral view.

Figure 5 - 11. Eutrichosomella yunnanensis sp. nov., holotype 5 head 6 antenna 7 mesosoma 8 forewing, inset shows postmarginal vein (pmv) and stigma vein (sv) 9 hindwing 10 legs 11 gaster.

Figure 12 - 15. Eutrichosomella yunnanensis sp. nov., paratype (♂) 12 antenna 13 mesosoma 14 forewing 15 genitalia.