Chelonus (Areselonus) sigiriyansis sp. nov.

(Figs 1–2)

urn:lsid:zoobank.org:act: 498AFD0B-3B13-4B21-9A8E-8F71D407D685

Material examined. Holotype, female, SRI LANKA: Sigiriya, 7°57’ N, 80°46’ E, 18.iii.1999, coll. C. J. Burwell (AIMB).

Description. Holotype, female, length of body 2.3 mm, of fore wing 1.6 mm.

Head. Antenna with 16 antennomeres, subapical antennomeres not broadened, shorter than basal antennomeres, apical antennomeres narrow (Fig. 1A); third antennomere as long as fourth; third, fourth and terminal antennomeres 3.7 ×, 3.7 × and 2.5 × longer than wide, respectively; head transverse, in dorsal view roundly contracted behind eyes (Fig. 1E); OOL: OD: POL= 2.3: 1.0: 1.8; longitudinal diameter of eye 1.5 × height of temples; vertex coarsely longitudinally striate-rugose (Fig. 1E); frons distinctly concave, transversely striate-rugose, smooth posteriorly with midlongitudinal carina (Fig. 1C); occiput longitudinally striate-rugose (Fig. 1E); temple longitudinally striate (Fig. 1F); face transversely reticulate-rugose (Figs 1B, D); clypeus moderately punctate, raised medially (Fig. 1D); length of malar space 2.3 × basal width of mandible.

Mesosoma. Length of mesosoma 1.4 × its height; pronotum rugose-reticulate laterally, smooth posteriorly (Fig. 1F); mesoscutum areolate-rugose (Fig. 2A); notauli impressed as large pits (Fig. 2A); transverse suture distinct, deep (Fig. 2A); scutellar sulcus divided by five carinae (Figs 2A–B); scutellum rugose, sparsely setose, with crenulate groove laterally (Figs 2A–B); mesopleuron evenly convex, coarsely reticulate-rugose, setose (Fig. 1F); metanotum crenulate with distinct midlongitudinal carina (Fig. 2B); propodeum with medial and lateral tubercles, coarsely reticulate-rugose, with inverted Y-shaped carina, transverse carina distinct and complete (Fig. 2B).

Wings. Fore wing hyaline apical half (Fig. 2F); length of fore wing 2.4 × its width; length of marginal cell 1.3 × pterostigma; vein 2-Rl present, indistinct (Fig. 2F); vein r as long as 3-SR (Fig. 2F); r: 3-SR: SRl = 1.0: 1.0: 3.5; SRl straight; parastigma distinctly swollen (Fig. 2F); 1-CU1: 2-CU1= 1.0: 4.4; vein CUlb present (Fig. 2F).

Legs. Hind coxa smooth, with dense short setae (Figs 2D–F); hind femur robust; length of hind femur, tibia and basitarsus 3.4 ×, 3.6 × and 4.3 × their maximum width respectively; mid and hind tibia with numerous short, pointed spines on apical half.

Metasoma. Metasomal carapace elongate-oval in dorsal view with spine like protuberance, coarsely reticulate-rugose, without midlongitudinal carinae basally (Fig. 2C); length of carapace 2.1 × its maximum width in dorsal view; carapace without undulating lamella laterally (Figs 2D–E); ventral cavity closed apically; ovipositor short, slender (Fig. 2D) and the ovipositor sheath 0.08 × as long as fore wing, 0.3 × as long as hind tibia.

Colour. Black except eyes, ocelli grey, basal antennomeres yellow; apical antennomeres, maxillary and labial palps, tegula, wing veins, pterostigma, legs brownish yellow to dark brown.

Male. Unknown.

Biology. Unknown.

Distribution. Sri Lanka.

Etymology. The species is named after the collection locality ‘Sigiriya’.

Comparative diagnosis. The new species comes closer to Chelonus (Areselonus) spinigaster Ahmad & Ghramh, 2018 described from India. Apart from the differences mentioned in the key, the new species differs from the latter in having OOL 1.2 × POL (1.5 × in C. (A.) spinigaster), F8–F11 slightly longer than wide (as long as wide in C. (A.) spinigaster), terminal antennomere 2.5 × as long as wide (2.0 × in C. (A.) spinigaster), mesosoma 1.4 × as long as high (1.2 × in C. (A.) spinigaster), coxae reddish brown (blackish brown in C. (A.) spinigaster).