Trichrysis kylan Wiśniowski & Cuong, 2020

Wiśniowski, Bogdan, Lien, Nguyen Thi Phuong & Cuong, Nguyen Quang, 2020, Discovery of four new species of Trichrysis Lichtenstein, cyanea species group (Hymenoptera, Chrysididae) from Vietnam, Zootaxa 4881 (1), pp. 165-178 : 173

Trichrysis kylan Wiśniowski & Cuong , sp. nov.

Material examined. Holotype, ♀: / VIET NAM; Tuyen Quang, Na / Hang , 20.ix.2017; MT, [leg.] KDL// VN 19/

Diagnosis. Middle sized species with slender body, and striking colouration of metasoma, with golden, green, blue, and purple colours ( Figs 16, 18 ). Sublateral, longitudinal carina on pronotum developed only on anterior part as anterolateral angle, faint in the middle and posterior half. Tegula dark-purple, metallic. T1 and T2 dark golden green, with large blue spots submedially and laterally. T3 golden green, dark blue anteriorly and with two large submedian spots ( Fig. 18 ). Pits large, apical rim wrinkled; apical teeth short, middle one pointed and downcurved, lateral teeth angulate. S2 spots subtriangular, fused to form quadrilateral mark, with small golden triangular area anteriorly; mark about 1.2 × wider than long (a ‘manta’ shape) ( Fig. 17 ).

Description. Female. Holotype. Body length 6.5 mm.

Head. Scapal basin deep and punctate, in central and lower part punctures shallower and interspaces wider, shining. Brow slight, TFC single, slightly inverted V-shaped, the area below with elongated punctures, with polished, shining interspaces ( Fig. 14 ). Brow above TFC slightly concave, with dense punctures ( Figs 13, 15 ). Relative length of P:F1:F2:F3=1.0:1.3:0.9:0.7; F1 l/w=2.4; OOL 2.0 × MOD; BOL 1.7 × MOD; POL 2.3 × MOD; MS 1.6 × MOD; clypeus almost truncated. Mandible without subapical tooth. Malar space with large punctures, and with genal carina reaching up to 2/3 of height of head, the carina branching at margin of compound eye. Setae on vertex whitish, longer than 1.0 × MOD. Ocellar triangle obtuse, densely punctured and punctures with black interspaces ( Fig.15 ).

Mesosoma. Median pronotal line absent. Sublateral, longitudinal carina on pronotum developed only in anterior part as anterolateral angle ( Fig. 15 ), faint in middle and posterior half. Tegula dark-purple, metallic. Punctuation on pronotum, mesoscutum and mesoscutellum dense, interspaces 0.1–0.6 × PD, shining and punctate. Interspaces on mesonotum partly darkened. Mesepisternum with large punctures, interspaces narrow, mostly 0.1–0.5 × PD. Episternal sulcus narrow, with punctures about as large as on mesepisternum; scrobal sulcus with large areolate punctures, about 2.0 × as large as punctures on mesepisternum ( Fig. 13 ). Wings only slightly brownish. Setae on outer edge of metatibia as long as their distal width.

Metasoma. Metasoma densely punctate; interspaces 0.3–0.7 × PD, polished, only with scattered tiny punctures. T1 with short median groove anteriorly, T2 without median carina. Pits large, apical rim wrinkled; apical teeth short, middle tooth pointed and downcurved, lateral teeth angulate. S2 spots subtriangular, forming quadrilateral mark, with small golden triangular area anteriorly; mark about 1.2 × wider than long ( Fig. 17 ).

Colouration. Body mostly golden green and blue with some purple. Head and mesosoma mainly golden and green, with blue hints ( Figs 13, 15 ). Scape, pedicel and F1 golden green, rest of flagellum black. Some black colour around ocelli, on mesonotum and mesoscutum. Blue colour is on anterior part of pronotum, and metanotum medially. Pleuron golden green with some blue shimmer. T1 and T2 dark golden green, with large blue and purple spots submedially and laterally. T3 golden green, dark blue anteriorly and with two large submedian blue purple spots fused anterolaterally with anterior dark blue band ( Fig. 18 ). Sterna and legs golden green, all tarsi brownish.

Male. Unknown.

Distribution. North-eastern Vietnam (Tuyen Quang Province).

Remarks. Trichrysis kylan sp. nov. is similar to T. coeruleamaculata Rosa, Wei & Xu, 2016 but is easy to distinguish by following characters: median pronotal line absent, mesosoma dorsally with dense punctuation, interspaces 0.1–0.6 × PD (versus median pronotal line deep, interspaces 0.2–1.0 × PD in T. coeruleamaculata ), T1 and T2 golden green laterally (versus blue in T. coeruleamaculata ), dark blue submedian spots on T3 fused anterolaterally with anterior dark blue band (versus round spots on T3 not fused with anterior dark blue band in T. coeru-leamaculata). T. kylan sp. nov. may be distinguished from T. aliciae sp. nov. by following characters: black mark on S2 1.2 × wider than long (versus longer than wide in T. aliciae sp. nov.), F1 all metallic green (versus F1 only basally with metallic shimmer, blackish distally in T. aliciae sp. nov.), OOL 2.0 × MOD; POL 2.3 × MOD; MS 1.6 × MOD (versus OOL 1.6 × MOD; POL 1.7 × MOD; MS 1.3 × MOD in T. aliciae sp. nov.).

Etymology. The specific name is a masculine noun in apposition and refers to a mythological creature known as ‘Ky Lan’ (in Vietnamese), which is extremely popular in stories and images in the region. The golden pattern on T3 has a form which may be interpreted as a head of a creature.

Figures

FIGURES 16–18. Trichrysis kylan sp. nov., holotype ♀. 16. Metasoma, lateral view. 17. S2, ventral view. 18. T3, dorsal view. Scale bar = 0.5 mm.

FIGURES 13–15. Trichrysis kylan sp. nov., holotype ♀. 13. Head and mesosoma, lateral view. 14. Head, frontal view. 15. Head, dorsal view. Scale bar = 0.5 mm.