Euceros flagellator, Riedel, 2025

Riedel, Matthias, 2025, Notes on some Asian species of Euceros GRAVENHORST, with description of a new species (Hymenoptera, Ichneumonidae, Eucerotinae), Linzer biologische Beiträge 57 (1), pp. 343-349 : 344-346

Euceros flagellator nov.sp. ( Figs 1-5 )

Holotype: (J) China, Jilin province, Da Gu Jia , 20 km SEE Jilin, 43°47'33 " N 126°46'48 " E, 350 m, 21.VI.2017, E. Jendek & O. Šauša (Linz).

E t y m o l o g y: The species name refers to the unique flagellar structure.

D e s c r i p t i o n: Body length 9.5 mm. Flagellum with>29 segments (tips broken off); flagellar segments 5-12 highly modified, segments 6-11 with long denticular extensions on outer side, segments 10-12 with small basal extensions on inner side; segments 9-12 with rows of small oval tyloids dorsally ( Fig. 3 ). Head large, temple slightly widened behind eye, finely punctate and shining ( Fig. 5 ). Ocelli small, distance between lateral ocellus and eye 2.1× ocellar diameter. Occipital carina complete, not excavated medially. Frons densely rugose-punctate, dull. Face with dense punctures, shining. Clypeus not separated from face, with sparse punctures and blunt apical margin ( Fig. 4 ). Mandibular teeth short, ventral tooth slightly smaller than dorsal tooth. Median process of pronotal collar (only partly visible) with shallow median excision. Mesoscutum with dense punctures, shiny. Notaulus sharply impressed in frontal third of mesoscutum. Mesopleuron and metapleuron densely punctate, shiny; speculum smooth. Propodeum rugose-punctate; apical area almost as long as basal area, with longitudinal rugae and median longitudinal ridge. Fore tibia without apical tooth. Hind trochantellus not flattened ventrally. Hind femur slender, 5.0× as long as high. All claws completely pectinate. Areolet of fore wing open, e. g. without vein 3rs-m. Vein M between veins 2rs-m and 2m-cu short. Vein 1cu-a postfurcal (fig. 2). 1 st tergite subsessile, 1.1× as long as wide; its spiracle protruding; latero-median carina in basal half. All tergites densely punctate, without swellings, shiny between punctures.

Color. Black. Flagellum brownish; flagellar segments 6-13 with ochreous external margins and segments 8-10 with internal ochreous stripes. Palps, mandible except teeth, clypeus, face, gena and ventral half of frontal orbit ivory. Mesosoma black; mesoscutum with two small antero-lateral yellow spots on each side ( Fig. 2 ); subtegular ridge with yellow spot, and mesopleuron with small yellow spot frontally. Tergites black; 2 nd to 4 th tergites with narrow yellow transverse basal bands, 7 th tergite reddish-brown. Fore and mid coxae black, yellow apically; fore and mid trochanters and all trochantelli yellow; fore and mid legs otherwise reddish-yellow, its femora ± blackish ventrally. Hind coxa, hind trochanter and hind femur black; hind tibia black, yellow in basal 0.2; hind tarsus except brown basal 2/3 of metatarsus yellow ( Fig. 2 ). Wings hyaline; pterostigma brown.

♀ unknown.

T a x o n o m i c a l r e m a r k. This new species can easily be identified by the unique flagellar structure and color pattern. In the key of non-Nearctic Euceros species ( BARRON 1978) the species runs to Euceros pectinis BARRON , but differs by its flagellum and different color patterns on mesosoma, metasoma and legs.

Despite a different color pattern, this specimen might represent the unknown male of Eucerus albibasalis UCHIDA due to a similar form of the pronotal process, but more material and/or genetical data are necessary to confirm a possible correlation of both sexes.

D i s t r i b u t i o n: Only known from Northern China.

Figures

Figs 1-2: Euceros flagellator nov.sp., holotype, J: (1) dorsal view, (2) lateral view.

Figs 3-5: Euceros flagellator nov.sp., holotype, ♁: (3) Flagellum, ventral view, (4) head, frontal view, (5) head, dorsal view.