Syzeuctus laoticus, Riedel, 2022

Riedel, Matthias, 2022, Contribution to the knowledge of Oriental Syzeuctus FÖRSTER (Hymenoptera, Ichneumonidae, Banchinae), with description of six new species, Linzer biologische Beiträge 54 (1), pp. 257-273 : 267-268

Syzeuctus laoticus nov.sp. ( figs 1 , 7 , 13 , 19 )

H o l o t y p e: (♀) Laos: Prov. Hua Phan Prov., Phon-Pan, Umg. Ort Ban Saleui, 20°13´30´´N 103°59´26´´E, 1350-1900 m, 20.06.2013 KJa, leg. C. Holzschuh & natives (Linz).

D e s c r i p t i o n: ♀: Body length 10.0 mm. Length of fore wing 7.5 mm and of ovipositor 9.5 mm. Antenna with 44 flagellomeres, filiform; 1 st flagellomere 3.7× longer than wide and 0.60× as long as eye; preapical flagellomere square. Temple short, strongly and roundly narrowed behind eye, dorsally 0.3× as long as eye. OED 1.3× and OOD 1.7× ocellar diameter. Vertex with scattered punctures. Frons with dense punctures, moderately swollen laterally and slightly impressed medially. Face densely punctate. Clypeus almost flat, 2.3× wider than long, apical margin rounded. MI 0.6. Mandible with baso-ventral lamella, lower tooth slightly shorter than upper tooth. Genal carina reaching mandibular base.

Mesosoma densely punctate, covered with grey setae, 1.50× longer than high. Frontoventral edge of pronotum moderately curved. Side of pronotum densely punctate, pronotal groove partly smooth. Epicnemial carina slightly elevated behind fore coxae, pleural part short, ending in ventral third of mesopleuron, transversal part present as short dentiform lamella. Pleural carina absent. Posterior transverse carina of propodeum shortly indicated laterally, widely absent medially. Legs slender; hind femur 5.8× longer than wide. Hind metatarsus 0.7× as long as hind femur. 2 nd hind tarsomere 1.5× as long as 3 rd one. Hind claw without teeth, strongly bent apically (c. 90°). Areolet with long stalk; vein 2m-cu reaching areolet in its distal 0.8. Vein 1cu-a postfurcal by 2× its width. Postnervulus intercepted behind its middle. Hind wing with 7 distal hamuli.

Metasoma slender, tergites with narrow spiracles, spiracles not bulged. 1 st tergite 2.6× longer than wide, with scattered punctures laterally, almost smooth medially, shining. 2 nd tergite 1.55× longer than wide, with dense punctures and long setae, ± shining. 3 rd tergite 1.25× as long as wide, with dense punctures and long setae, ± shining. Ovipositor 1.25× as long as fore wing, 1.6× as long as metasoma and 3.5× longer than hind tibia.

Color: Black. Flagellum black. Palps, mandible except teeth, clypeus, face except short median black stripe below antennae, gena, complete orbits, ventral spots of scape and pedicel, propleuron, frontal margin and large triangular spot on upper margins of pronotum, tegula, subtegular ridge, anterolateral and central spots on mesoscutum, longitudinal band on mesopleuron, upper division and apical spot of metapleuron, scutellum except black median stripe, postscutellum, area spiracularis frontally and wide posterior band of propodeum confluent with spot on metapleuron yellow. 1 st tergite yellow in basal 1/4, 1 st to 4 th tergites with apical yellow bands. 7 th tergite ± reddish. Sternites including hypopygium yellowish. Fore and mid legs entirely yellow. Hind coxa yellow, with black spots internally and laterally; hind trochanter black, hind trochantellus yellow; hind femur black, with yellow band in apical 0.1; hind tibia yellow, infscuate in apical 0.25. Hind tarsus black, bases of 1 st to 3 rd tarsomeres and 4 th hind tarsomere entirely yellow. Wings hyaline; fore wing with weak apical brownish spot. Pterostigma brown.

♁ unknown.

R e m a r k: This new species belongs to the zanthorius group sensu CHANDRA & GUPTA (1977) and runs to S. torrevillasi MOMOI, 1971 due its largely absent posterior transversal carina of propodeum. It differs from S. torrevillasi by its completely and densely punctate metapleuron and propodeum, postfurcal vein 1cu-a of fore wing and black 5 th and 6 th tergite without yellow bands.

Its color pattern also resembles S. flavofacialis KANG & LEE, 2020 (in KANG et al. 2020), but differs by its slenderer basal tergites, and slightly different coloration of hind coxa and hind tarsus.

Figures

Figs 1-3: Habitus from dorsal: (1) Syzeuctus laoticus nov.sp. ♀ holotype (HT); (2) S. siamensis nov.sp. ♀ HT; (3) S. orientalis nov.sp. ♁ paratype (PT).

Figs 4-9: Basal tergites from dorsal: (4) Syzeuctus achterbergi nov.sp. ♀ HT; (5) S. floresiensis nov.sp. ♀ HT; (6) S. genator nov.sp. ♀ HT; (7) S. laoticus nov.sp. ♀ HT; (8) S. orientalis nov.sp. ♁ PT; (9) S. siamensis nov.sp. ♀ HT.

Figs 10-15: Faces from frontal: (10) Syzeuctus achterbergi nov.sp. ♀ HT; (11) S. floresiensis nov.sp. ♀ HT; (12) S. genator nov.sp. ♀ HT; (13) S. laoticus nov.sp. ♀ HT; (14) S. orientalis nov.sp. ♁ HT; (15) S. siamensis nov.sp. ♀ HT.

Figs 16-21: Heads from frontal: (16) Syzeuctus achterbergi nov.sp. ♀ HT; (17) S. floresiensis nov.sp. ♀ HT; (18) S. genator nov.sp. ♀ HT; (19) S. laoticus nov.sp. ♀ HT; (20) S. orientalis nov.sp. ♁ HT; (21) S. siamensis nov.sp. ♀ HT.