Rhadinoscelidia lixa Hisasue & Mita, 2020

Hisasue, Yu & Mita, Toshiharu, 2020, Rhadinoscelidia lixa sp. nov. (Hymenoptera, Chrysididae, Loboscelidiinae) found on an ant nest in Thailand, ZooKeys 975, pp. 1-9 : 1

Rhadinoscelidia lixa Hisasue & Mita sp. nov. Figs 1 , 2-5 , 6-7

Material examined.

Holotype, ♀, Thailand, Phrae Prov. 153 m, Mang Chin Dist., nr. Wiang Kosai NP, 3. V. 2019, R. Ishikawa leg. (Entomological Laboratory, Faculty of Agriculture, Kyushu University).

Description of holotype.

Female (Fig. 1 ). Body 3.0 mm long.

Head. Head (Figs 2-4 ) 1.9 times as long as height in lateral view, 1.3 times as long as maximum width; minimum length between compound eyes 0.7 times as long as head width; frontal projection rectangular in frontal view (Fig. 3 ); apical margin of frontal projection depressed (Fig. 2 ); malar space striate; frons striate radially except smooth appressed area in front of midocellus (Fig. 2 ); low ridge present from around posterior part of inner orbit of eye to posterior depression of vertex; vertex without transverse ridge, deeply depressed posteriorly; cervical expansion curved in lateral view (Fig. 4 ); temple 3.3 times as long as MOD; POL 2.5 times as LOD; OOL 3.0 times as long as LOD; LOL as long as LOD; scape 4.3 times as long as wide, sparsely punctate, slightly curved, 0.8 times as long as head width (Fig. 5 ); flange of scape 0.3 times as long as scape length; maximum width of flange 0.6 times as wide as tubular part of scape (Fig. 5 ); pedicel 1.3 times as long as wide, 0.5 times less than F1; F1-F7 tubular; relative length (width) of F1-F11: 2.4 (1.1): 2.0 (1.2): 1.8 (1.2): 1.6 (1.0): 1.4 (1.0): 1.4 (1.0): 1.4 (1.0): 1.4 (1.1): 1.4 (1.1): 1.4 (1.1): 3.2 (1.2).

Mesosoma. Mesosoma polished (Figs 1 , 6 ); pronotum 0.9 times as long as maximum width; maximum width of pronotum 1.5 times as wide as posterior width; lateral margin of pronotum without distinct ridge (Fig. 6 ); mesoscutum 1.1 times as long as wide; tegula polished, 1.5 times as long as wide (Fig. 6 ); mesoscutum with notauli reaching posterior margin; mesoscutellum polished, 1.6 times as long as maximum width, 4.4 times as long as metanotum length (Fig. 7 ); length between metanotal depressions 1.5 times as long as length of metanotum (Fig. 7 ); propodeum smooth; projection weakly developed; dorsal margin of propodeum concave above foramen (Figs 1 , 7 ).

Legs. Legs polished (Fig. 1 ); femora cylindrical; tibiae slightly flattened, with longitudinal ridge on lower side; forefemur 4.1 times width; foretibia 5.9 times as long as width; midfemur 4.8 times as long as width; midtibia 6.6 times as long as width; hindcoxa 2.4 times as long as hindtrochanter; hindfemur 5.1 times as long as maximum width, 1.5 times as long as head width; hindtibia nearly straight, 8.1 times as long as maximum width (Fig. 1 ); hindbasitarsus 0.55 times as long as head width; relative length of hindtarsomeres = 3.5: 1.8: 1.7: 1: 2.3; tarsal claws with median tooth.

Wings. Fore and hindwings broken, missing from basal portion (Figs 6 , 7 ).

Metasoma. Metasoma polished and smooth.

Pilosity. Frons with sparse decumbent needle-like setae; eye without setae; frontal projection with dense erect needle-like or cuneate setae (Fig. 2 ); clypeus with sparse erect needle-like setae (Fig. 3 ); maxilla with dense decumbent needle-like setae; labrum with dense decumbent needle-like setae; malar space with sparse suberect cuneate or forked setae (Fig. 4 ); temple with sparse decumbent needle-like setae; vertex behind ocelli with sparse suberect needle-like setae; vertex with ribbon-like setae, shorter than ribbon-like setae on cervical expansion (Figs 2 , 4 ); cervical expansion with sparse decumbent needle-like setae and ribbon-like setae, longer than ribbon-like setae on vertex; upper gena with ribbon-like setae, as long as ribbon-like setae on pronotum (Fig. 4 ); lower gena with sparse suberect needle-like setae along occipital carina; scape with sparse decumbent needle-like setae and sparse suberect forked setae (Fig. 5 ); pedicel with dense decumbent needle-like setae; F with dense decumbent needle-like setae, shorter than each F length (Fig. 5 ).

Anterior margin of pronotum with ribbon-like setae (Fig. 6 ), as long as those on lower gena; pronotum with sparse suberect cuneate or forked setae in dorsal view (Fig. 6 ); pronotum with sparse decumbent cuneate or forked setae in lateral view; propleuron with sparse decumbent cuneate or forked setae (Fig. 1 ); mesoscutum with sparse suberect forked setae (Fig. 6 ); tegula with sparse suberect forked setae (Fig. 6 ); mesopleuron with sparse decumbent cuneate or forked setae; metanotum with sparse suberect forked setae (Fig. 7 ); propodeum with sparse suberect cuneate setae in lateral view (Fig. 7 ).

Apical half of fore and midcoxae with dense suberect needle-like setae (Fig. 1 ); femora with sparse erect or suberect cuneate setae (Fig. 1 ); apical part of coxae with dense decumbent cuneate setae; tibiae with dense decumbent needle-like setae; tarsomeres with dense decumbent needle-like setae.

T2-T3 with sparse decumbent setae (Fig. 1 ), shorter than setae on S3-S4; S3-S4 with sparse suberect needle-like setae (Fig. 1 ); T5 with sparse suberect needle-like setae; S5 with dense suberect needle-like setae.

Coloration. Body reddish-brown (Fig. 1 ); labial palpi, maxillary palpi, and ribbon-like setae brownish yellow; other setae white; flange yellowish brown.

Male. Unknown.

Etymology.

Named after the Latin ‘lixa’, meaning camp-follower, referring to the wasp walking near the ant’s trail.

Distribution.

Thailand (Phrae).

Associate.

Carebara diversa ( Hymenoptera , Formicidae ) (Fig. 8 ).

Remarks.

Rhadinoscelidia lixa sp. nov. is easily distinguished from other species by the following characters: scape 4.3 times as long as width (over 5 times as long as width in other species); short erect setae of antenna; wide ribbon-like setae on temple wider than those on pronotum (shorter than those on pronotum in other species); shorter ribbon-like setae on cervical expansion (relatively longer in other species); straight hindtibia (slightly or moderately curved hindtibia in other species).

Figures

Figure 1. Lateral habitus of Radinoscelidia lixa sp. nov. (holotype). Scale bar: 1 mm.

Figure 8. Lateral habitus of Carebara diversa. Scale bar: 1 mm.

Figures 2 - 5. Head of Radinoscelidia lixa sp. nov. (holotype) 2 dorsal 3 frontal 4 lateral 5 antenna. Scale bars: 0.5 mm.

Figures 6, 7. Mesosoma of Radinoscelidia lixa sp. nov. (holotype) 6 dorsal 7 lateral. Scale bars: 0.5 mm.