Achaius sabahensis, Riedel, 2023

Riedel, Matthias, 2023, Contribution to the knowledge of the Ichneumoninae (Hymenoptera, Ichneumonidae) from Maritime Southeast Asia, Zootaxa 5363 (1), pp. 1-94 : 9-11

Achaius sabahensis nov. sp.

( Figs 2A–D )

Holotype. (♀) Malaysia: Sabah, Kinabalu Park Head Q., 8–11.iii.1987, c 1600 m, Malaise trap 1, C. van Achterberg, RMNH´87 (Leiden).

Description. ♀. Body length 10.5 mm.

Head. Flagellum with 40 flagellomeres, slender, almost filiform; 1 st flagellomere 3.7 × longer than wide, widest flagellomeres 1.2 × longer than wider. Temple rather long, distinctly and linearly narrowed behind eye (fig. 2B). OED 1.0 × and OOD 1.1 × ocellar diameter. Frons smooth ventrally, transversely rugose-punctate dorsally. Face densely punctate, shining. Clypeus almost flat, with sparse punctures; apical margin sharp and slightly concave (fig. 2A). Mandible long, with two teeth, ventral tooth smaller than dorsal one. Malar space 1.2 × as long as width of mandibular base. Gena with sparse fine punctures. Genal carina reaching hypostomal carina away from mandibular base.

Mesosoma . Side of pronotum densely punctate dorsally, with irregular rugae ventrally. Notaulus indistinct. Mesoscutum finely and densely punctate, slightly shining. Mesopleuron densely punctate and finely striate ventrally, densely punctate dorsally; speculum smooth. Metapleuron rugose-punctate; juxtacoxal carina present. Scutellum moderately elevated, about as long as wide, with fine sparse punctures; without lateral carina. Propodeum (fig. 2C) rugose, with distinct blunt apophysis; spiracle slit-shaped. Area basalis not carinated, without median tubercle. Area superomedia almost rectangular, 1.4 × longer than wide; costula absent. Hind coxa densely punctate, without scopa. Hind femur slender, densely punctate, 5.1 × longer than wide. Claws simple. Areolet pentagonal, frontal distance between veins 2rs-m and 3rs-m 5 × their diameter. Vein 1cu-a postfurcal by 3.0 × its width.

Metasoma. Strongly amblypygous; hypopygium unmodified, with fine setae, reaching metasomal apex. 2 nd and 3 rd sternites with median folds. Postpetiole moderately widened, without latero-median carina; median field moderately elevated, finely rugose; lateral field punctate. Gastrocoelus impressed, without ridges. Thyridium very small, oblique, 0.2 × as wide as the interval between thyridia (fig. 2D). 2 nd tergite as long as wide, finely rugose and slightly aciculate in basal half, granulate apically, ± dull. Following tergites finely granulate, shining. Ovipositor sheath not reaching behind metasomal apex.

Colour. Black. Flagellum black; flagellomeres 8–12 brownish dorsally. Face and gena with dark reddish suffusion; frontal orbit with reddish-yellow stripe. Hind edge of pronotum, tegula, subtegular ridge, central spot of mesoscutum and scutellum reddish. Tergites dark reddish-brown; 7 th tergite with ivory median spot. Legs black; fore and mid femora and tibia reddish-yellow stripes frontally; hind tibia diffusely reddish-brown sub-basally. Wings hyaline; pterostigma blackish.

♂ unknown.

Remarks. This new species runs to Achaius flavorufus Heinrich, 1965 in the key of the Oriental Achaius species ( Heinrich 1965: 111–112), but differs from all known Oriental species by the strong reduction of pale coloration.

Distribution. Only known from Borneo.

Figures

FIGURE 2. Achaius sabahensis n. sp. HT ♀. A face, frontal view, B head, dorsal view, C propodeum, dorsal view, D basal tergites, dorsal view.