Mesochorus rufoscutellaris, Riedel, 2019

Riedel, Matthias, 2019, Contribution to the Mesochorinae (Hymenoptera, Ichneumonidae) of Nepal, Linzer biologische Beiträge 51 (2), pp. 1163-1174 : 1166-1167

Mesochorus rufoscutellaris nov.sp. ( figs 20-29 )

Holotype: (♀) Nepal, Prov. Karnali, 29°11´54´´N 82°18´36´´E Gothichaur, 2850 m, Sumpfwiese , 26.V.-05.VI.2007, leg. F. Creutzburg ( Erfurt ).

Paratype: (♂) Nepal, Prov. Karnali, 29°11´54´´N 82°18´36´´E Gothichaur, Hochtal , Zeltplatz hinten, WS 2850 m, 5.VI.2007, leg. J. Weipert ( Erfurt ).

Description: ♀: Body length 5.6 mm. Flagellum with 38 flagellomeres; 1 st flagellomere length 5.8x width and 0.70x eye length; 2 nd flagellomere length 4.2x width; preapical flagellomere 1.8x longer than wide. Temple moderately and roundly narrowed behind eye, dorsally c. 0.7x as long as eye. Distance of lateral ocellus to eye 1.0x ocellar diameter. Frons punctate, with fine transverse striae above antennal grooves. Face coarsely rugose-punctate, with central rim in dorsal half, 1.1x wider than length of face+clypeus and 1.0 as wide as eye length; inner eye margins parallel. Subantennal transverse carina dipped medially. Ventral 1/3 of facial orbit and malar space with oblique striae. Clypeus densely punctate. Malar space 0.3x as long as width of mandibular base. Mandible with two equal teeth. Genal carina reaching hypostomal carina away from mandibular base, both carinae low.

Side of pronotum coarsely punctate, rugose ventrally. Mesoscutum coarsely punctate, shining. Mesopleuron with very dense coarse punctures, speculum smooth. Metapleuron with finer dense punctures. Scutellum without lateral carina or apical tubercle, rounded in profile. Propodeum completely carinate. Area basalis rectangular, c. 1.2x longer than wide. Area superomedia 2.1x longer than wide and 1.4x longer than area petiolaris; costula reaching area superomedia in its frontal 0.4. Area petiolaris about as long as wide, with some coarse rugae. Hind femur 5.7x longer than wide; hind metatarsus 0.45x as long as hind tibia; distal fore tarsomere slender, 2.9x longer than wide; hind claw with c. 5 long teeth.

Areolet slightly wider than long, pointed; 2nd recurrent vein in its middle. Nervulus interstitial. Nervellus of hind wing not intercepted; discoidella absent.

1 st tergite 3.3x longer than wide. Postpetiolus with weak central rim and some longitudinal rugae, without lateral carina. 2 nd tergite 1.05x wider than long; thyridium transversely

oval. Ovipositor sheath entirely pilose, 7.8x longer than wide and as long as hind metatarsus, moderately narrowed in apical 0.25.

Colour: Black. Antenna brownish. Palps, clypeus, mandible except teeth, gena, wide facial orbit and triangular spot beside antennal groove cream-yellow. Face brownishblack centrally. Vertical and outer orbits reddish. Mesosoma black; wide upper margin of pronotum, H-shaped median spot on mesoscutum and scutellum (except small brownish basal spot) red; dorsal half of mesopleuron dark reddish. Metasoma black; 2 nd tergite with narrow cream-yellow hind margin; epipleura of 2 nd and 3 rd tergites and median folds of 2 nd to 3 rd sternites cream-yellow. Legs red; all distal tarsomeres reddish-brown; hind tibia yellow, narrowly infuscate apically (by 0.5x its width). Pterostigma hyaline, with ochreous margins.

♂: Body length 5.5 mm. Flagellum with 35 flagellomeres. Temple shortly parallel behind eye, moderately narrowed apically. Distance of lateral ocellus to eye 1.1x ocellar width. Face densely rugose-punctate, width 1.1x length of clypeus+face and 0.9x eye length. Clypeus punctate. Malar space 0.4x as long as width of mandibular base. Hind femur 5.4x longer than wide; hind metatarsus 0.48x as long as hind tibia; hind claw with 4 basal teeth. 1 st tergite 2.9x longer than wide; postpetiolus with distinct longitudinal striae. 2 nd tergite 1.1x longer than wide. Clasper long, measured without basal body c. 1.7x longer than 2 nd hind tarsomere, stab-shaped, slightly clubbed apically. Structure otherwise as described for the ♀.

Colour: Face reddish, darkened below antennal grooves. Pronotum largely reddish; mesopleuron reddish dorsally and with diffuse dark reddish suffusion ventrally; mesoscutum reddish, with one antero-medial and two lateral black stripes. Metasoma black; 2 nd tergite with narrow cream-yellow apical margin; epipleura of 2 nd and 3 rd tergites reddish; median folds of 2 nd to 6 th sternites cream-yellow. Legs reddish; hind tibia yellowish, blackish in apical 0.1 (1x tibial width); distal tarsomeres brown. Pterostigma ochreous, with brownish margins. Colouration otherwise as described for the ♀.

Remark: This species belongs to the angustatus -group of Mesochorus sensu SCHWENKE (1999) (e.g. all tergites black). It is characterized by the densely rugosepunctate face, densely punctate mesopleuron, and characteristical colouration of mesosoma. In the key of Nepalese Mesochorus species ( KUSIGEMATI 1988), it runs to M. nepalensis KUSIGEMATI and M. interruptus KUSIGEMATI, but differs by the above mentioned features.

Figures

Figs 20-25: Mesochorus rufoscutellaris nov.sp. ♀: (20) habitus, (21) face, (22) propodeum, (23) mesopleuron, (24) ovipositor sheath, (25) hind claw.

Figs 26-29: Mesochorus rufoscutellaris nov.sp. ♂: (26) face, (27) head from dorsal, (28) mesopleuron, (29) stylets.