Pediobius sasae sp. nov.

Figs 1–15

Diagnosis

Upper half of occiput strongly concave (Fig. 6); occipital margin strongly carinate, especially strong in the dorsolateral corners of the occiput (Fig. 7); transverse pronotal carina weakly developed or absent (Fig. 11).

Description

Length of body female 2.5–3.4 mm, male 2.0– 2.7 mm.

Female (Figs 1–2), colour: Scape golden­green, pedicel and flagellomeres 1–3 dark brown with a metallic tinge, flagellomeres 4–5 pale brown, or all flagellomeres dark brown with a metallic tinge. Frons golden­red with golden­green spots, to entirely goldengreen; lower face and malar space metallic purple. Vertex dark golden­purple. Mesoscutum golden­green, sometimes with a metallic blue tinge. Scutellum and axillae dark golden­purple. Dorsellum and propodeum golden­green, sometimes with a metallic blue tinge. Coxae, femora and tibiae golden­green with a metallic blue tinge; tarsal segments 1–3 yellowish­white, segment 4 dark brown. Wings hyaline. Petiole dark golden­purple. Gaster with first tergite golden­green, remaining tergites dark goldenpurple.

Antenna as in Fig. 15, i.e. with ratios of the length of scape/pedicel/flagellomeres 1 to 5: 3.9:1.0:1.8:1.6:1.4:1.1:1.2. Frons with weak reticulation, shiny; frontal suture V­shaped; antennal scrobes as distinct narrow grooves, joining frontal suture separately. Vertex with strong reticulation. Malar sulcus absent or indicated by fine and small meshed reticulation. Occipital margin with a strong carina. Eyes with scattered short hairs. Ratios of height of head/width of head 0.71:1; length of head/width of head 0.52:1; height of eye/malar space/ width of mouth opening 6.9:1.0:4.3; distances between posterior ocelli/between posterior ocelli and eye/between posterior ocelli and occipital margin 8.0:4.0:1.0; width of head/ width of thorax across shoulders 1.3:1.

Thoracic dorsum strongly convex. Pronotum well developed, with a weakly developed transverse carina close to posterior margin, carina absent in some specimens. Mesoscutum with strong reticulation; notaular depressions indistinct, entirely reticulate. With a short but wide hole between midlobe of mesoscutum and scutellum. Scutellum strongly convex with strong reticulation throughout. Dorsellum flat and smooth, with two shallow foveae anterolaterally. Propodeum smooth and shiny; submedian carinae closest medially, diverging posteriorly and anteriorly from this point; propodeal callus with two setae. Fore wing speculum closed below. Ratios of length of fore wing/length of marginal vein/height of fore wing 1.9:1.3:1.0; length of postmarginal vein/length of stigmal vein 1.5:1.

Petiole 0.83X as long as wide, with strong small meshed reticulation. Gaster elongate with posterior part pointed; first tergite smooth and shiny, remaining tergites with fine reticulation and with posterior margin smooth and shiny. Ratio of length of mesosoma/ length of gaster 0.58–0.61:1.

Male (Fig. 3), colour: Scape metallic bluish­green; flagellum with flagellomere 5 slightly paler than 1–4, all flagellomeres with metallic tinges. Frons golden­green with metallic blue tinges. Scutellum entirely dark golden­purple as in female, or with median part dark golden­purple and with sides and posterior part metallic bluish­green. Mesoscutum, dorsellum and propodeum metallic bluish­green. Gaster with first tergite metallic bluish­green with purple tinges. Colour otherwise as in female.

Antenna as in Fig. 14, i.e. with ratios of the length of scape/pedicel/flagellomeres 1 to 5: 3.5:1.0:2.6:2.5:2.6:2.5:3.0. Ratios of height of head/width of head 0.70:1; length of head/width of head 0.43:1; height of eye/malar space/width of mouth opening 2.6:1.0:1.8; distances between posterior ocelli/between posterior ocelli and eye/between posterior ocelli and occipital margin 9.0:5.0:1.0; width of head/width of thorax across shoulders 1.3:1. Head otherwise as in female.

Ratios of length of fore wing/length of marginal vein/height of fore wing 1.8:1.1:1.0; length of postmarginal vein/length of stigmal vein 1.5:1. Mesosoma otherwise as in female.

Petiole 1.3–1.7X as long as wide. Genitalia as in most species of subfamily Entedoninae (Hansson 1996) (Fig. 10), i.e. with digitus as long as wide, two equally large digital spines, volsellar setae short and relatively slender, and parameres only slightly protruding. Ratio of length of mesosoma/length of gaster 1.2–1.5:1. Petiole and gaster otherwise as in female.

Description

Length of body female 2.5–3.4 mm, male 2.0– 2.7 mm.

Female (Figs 1–2), colour: Scape golden­green, pedicel and flagellomeres 1–3 dark brown with a metallic tinge, flagellomeres 4–5 pale brown, or all flagellomeres dark brown with a metallic tinge. Frons golden­red with golden­green spots, to entirely goldengreen; lower face and malar space metallic purple. Vertex dark golden­purple. Mesoscutum golden­green, sometimes with a metallic blue tinge. Scutellum and axillae dark golden­purple. Dorsellum and propodeum golden­green, sometimes with a metallic blue tinge. Coxae, femora and tibiae golden­green with a metallic blue tinge; tarsal segments 1–3 yellowish­white, segment 4 dark brown. Wings hyaline. Petiole dark golden­purple. Gaster with first tergite golden­green, remaining tergites dark goldenpurple.

Antenna as in Fig. 15, i.e. with ratios of the length of scape/pedicel/flagellomeres 1 to 5: 3.9:1.0:1.8:1.6:1.4:1.1:1.2. Frons with weak reticulation, shiny; frontal suture V­shaped; antennal scrobes as distinct narrow grooves, joining frontal suture separately. Vertex with strong reticulation. Malar sulcus absent or indicated by fine and small meshed reticulation. Occipital margin with a strong carina. Eyes with scattered short hairs. Ratios of height of head/width of head 0.71:1; length of head/width of head 0.52:1; height of eye/malar space/ width of mouth opening 6.9:1.0:4.3; distances between posterior ocelli/between posterior ocelli and eye/between posterior ocelli and occipital margin 8.0:4.0:1.0; width of head/ width of thorax across shoulders 1.3:1.

Thoracic dorsum strongly convex. Pronotum well developed, with a weakly developed transverse carina close to posterior margin, carina absent in some specimens. Mesoscutum with strong reticulation; notaular depressions indistinct, entirely reticulate. With a short but wide hole between midlobe of mesoscutum and scutellum. Scutellum strongly convex with strong reticulation throughout. Dorsellum flat and smooth, with two shallow foveae anterolaterally. Propodeum smooth and shiny; submedian carinae closest medially, diverging posteriorly and anteriorly from this point; propodeal callus with two setae. Fore wing speculum closed below. Ratios of length of fore wing/length of marginal vein/height of fore wing 1.9:1.3:1.0; length of postmarginal vein/length of stigmal vein 1.5:1.

Petiole 0.83X as long as wide, with strong small meshed reticulation. Gaster elongate with posterior part pointed; first tergite smooth and shiny, remaining tergites with fine reticulation and with posterior margin smooth and shiny. Ratio of length of mesosoma/ length of gaster 0.58–0.61:1.

Male (Fig. 3), colour: Scape metallic bluish­green; flagellum with flagellomere 5 slightly paler than 1–4, all flagellomeres with metallic tinges. Frons golden­green with metallic blue tinges. Scutellum entirely dark golden­purple as in female, or with median part dark golden­purple and with sides and posterior part metallic bluish­green. Mesoscutum, dorsellum and propodeum metallic bluish­green. Gaster with first tergite metallic bluish­green with purple tinges. Colour otherwise as in female.

Antenna as in Fig. 14, i.e. with ratios of the length of scape/pedicel/flagellomeres 1 to 5: 3.5:1.0:2.6:2.5:2.6:2.5:3.0. Ratios of height of head/width of head 0.70:1; length of head/width of head 0.43:1; height of eye/malar space/width of mouth opening 2.6:1.0:1.8; distances between posterior ocelli/between posterior ocelli and eye/between posterior ocelli and occipital margin 9.0:5.0:1.0; width of head/width of thorax across shoulders 1.3:1. Head otherwise as in female.

Ratios of length of fore wing/length of marginal vein/height of fore wing 1.8:1.1:1.0; length of postmarginal vein/length of stigmal vein 1.5:1. Mesosoma otherwise as in female.

Petiole 1.3–1.7X as long as wide. Genitalia as in most species of subfamily Entedoninae (Hansson 1996) (Fig. 10), i.e. with digitus as long as wide, two equally large digital spines, volsellar setae short and relatively slender, and parameres only slightly protruding. Ratio of length of mesosoma/length of gaster 1.2–1.5:1. Petiole and gaster otherwise as in female.

volsellar setae.

Biology

Parasitoid of an unidentified gall midge belonging to the tribe Oligotrophini (Diptera: Cecidomyiidae) forming galls on dwarf bamboo (Sasa nipponica Makino & Shibata). Possibly also a hyperparasitoid of Torymus sp. (Hymenoptera: Torymidae).

Distribution

Japan (Nara Prefecture, Mt. Ôdaigahara).

Material examined

Holotype female labeled “ Japan: Nara Prefecture, Mt. Ôdaigahara, 34°11’N, 136°06’E, 1540 m, 24.iv.2003, A. Ueda” (Lund University Zoology Museum, Sweden). Paratypes: 79 females and 50 males with same label data as holotype (Australian National Insect Collection, Canberra; Canadian National Collection of Insects, Ottawa; collection of Christer Hansson; Hokkaido University Museum, Japan; Lund University Zoology Museum, Sweden; Natural History Museum, London, England; Smithsonian National Museum of Natural History, Washington, D.C., U.S.A.; Texas A&M University collection, College Station, U.S.A.; University of California, Riverside, U.S.A.).