Orthocentrus tenuiventris Humala & Lee, 2020

Humala, Andrei E., Lee, Jong-Wook & Choi, Jin-Kyung, 2020, A review of the genus Orthocentrus Gravenhorst (Hymenoptera, Ichneumonidae, Orthocentrinae) from South Korea, Journal of Hymenoptera Research 75, pp. 15-65 : 15

23. Orthocentrus tenuiventris Humala & Lee sp. nov.

Fig. 16

Description.

Female. Fore wing length 3.0-3.5 mm.

Face at level of antennal sockets 1.1 times as wide as high; face smooth and densely punctate, eyes not setose, dorsal ridge of face in between antennal sockets without a median prominence; face profile straight, slightly impressed dorsally, edge of clypeus straight, antennal sockets on a shelf; subocular sulcus distinct, bent towards occiput; maxillary palp long, reaching beyond to fore coxa. In dorsal view, head posteriorly slightly concave, temples distinct, lateral ocellus distant from eye by its maximum diameter, POL as long as diameter of lateral ocellus. Minimum distance between antennal sockets about 0.6 × of the diameter of socket; antenna with 31-36 flagellomeres (n=10) which gradually shortening towards apex; first flagellomere 2.3-2.5 times as long as wide and about 1/2 of the scape length; scape nearly parallel-sided.

Mesosoma smooth and polished except pronotum with short striations postero-ventrally, propodeum coriaceous with punctures; mesoscutum with distinct notauli; in profile, scutellum somewhat high, metapleuron not convex; propodeum without posterior transverse carina between lateral longitudinal carinae, lateromedian longitudinal carinae weak but complete, lateral longitudinal carinae weak, present posteriorly, spiracle small.

Legs slightly flattened; coxae and femora polished, tibiae and tarsi coriaceous; hind femur 3.4 times as long as high, hind tibia 3.8 times as long as apically wide; tibiae with spine-like setae, spurs of hind tibia distinctly curved apically.

Wings somewhat narrow, cells thus comparatively long and narrow; fore wing with areolet closed, large, conspicuously transverse, 2m-cu meeting areolet at apical 0.7, vein Rs gently bent towards wing apex; vein cu-a clearly distad of Rs&M; nervellus angled in the middle.

First tergite elongate, slightly widening posteriorly, 2.5-3.1 times as long as posteriorly wide; coriaceous-strigose, with weak lateromedian longitudinal carinae, with shallow transverse impressions originating at about middle of tergite, sloping posteriorly, not meeting centrally. Second tergite parallel-sided, 2.0-2.9 times as long as posteriorly wide; coriaceous, longitudinally striate, with shallow transverse impressions originating at about middle of tergite, sloping posteriorly, polished apically; small thyridia oval. Third tergite elongate, 2.0-2.9 times as long as posteriorly wide, coriaceous, longitudinally striate, polished posteriorly. Remaining tergites unsculptured. Ovipositor thick basally, strongly narrowed and pointed apically, straight, without notch; ovipositor sheath parallel-sided, with dense setae longer than sheath width and strongly curved, backwards pointing.

Body largely setose except eyes, pronotum, mesopleuron and metapleuron; setae conspicuous on tergites and sternites from metasomal segment 3, and very scattered on anterior tergites and posterior sides of coxae.

Dark brown except propleuron, hind corners of pronotum, lower mesopleuron yellowish; antenna, legs, clypeus dull yellow; mouthparts, tegula, and sternites creamy.

Male. Similar to female but laterally paler, creamy white, and antenna pale yellow, creamy white basally; antenna with 29 flagellomeres (n = 2). Otherwise as in female.

Biology.

Hosts unknown.

Etymology.

Named from the Latin tenuis (thin, slender) and venter (abdomen) after its long and narrow metasoma.

Comparison.

This is a distinctive species on account of the unusually long and slender metasoma (Fig. 16A ), the anterior tergites of which are strongly elongate and longitudinally striate (Fig. 16G ); the wings are narrow, antenna with 31-36 flagellomeres, basal flagellomere 2.3-2.5 times as long as wide.

Material examined.

Holotype: female; South Korea, JN: Gwangyang-si , Okryong-myeon , Chusan-ri, Mt. Baekun, MT (DNUE).

Paratypes: South Korea, GB: 1♀, Mungyeong-si Mungyeong-eup Sangcho-ri 288-1 Mungyeongsaejae 10.VI.1992 (DNUE-0248); 1♀, Uljin-gun , Mt. Baekamsan , 20.VI-12.VII.1999, D.S. Ku leg. (NIAS); GG: 2♀, Annyang-si , Manan-gu , Gwanaksan , 37°25'06"N, 126°50'56"E, 26.VI-4.VII.2007, J.W. Lim leg. (DNUE-0233,0234); 3♀, Gapyeong-si, Cheongpyeong-myeon Soseong-ri, Mt. Homyeong , 37°43'15"N, 127°29'18.9"E, 11-25.VII.2009, J.O. Lim leg. (DNUE-0906, ZIN-0904,0905); 1♀, Pocheon-si, Soheul-eup, Jikdong-ri, 51-7, Korean National Arboretum, 37°45'9.1"N, 127°08'34.4"E, MT 4, 14-28.VI.2013, I.G. Kim leg. (ZIN); GW: 1♀, Donghae-si, Samhwa-dong, Mureung valley, MT, 16-28.VI.2005, J.W. Lee leg. (ZIN-0118); 2♂, Mt. Taebaeksan, Yuilsa, MT, 20.VI-11.VII.1999, D.S. Ku leg. (NIAS); JB: 1♀, Jeongeup-si, Samgan-dong, Dapgok-ri, MT, 18.VI.2006, J.W. Lee leg. (DNUE-0401) .

Distribution.

South Korea (GB, GG, GW, JB, JN).

Figures

Figure 16. Orthocentrus tenuiventris sp. nov. Holotype. A Habitus in lateral view B head in frontal view C head in dorsal view D head and mesosoma in lateral view E mesosoma in dorsal view F fore wing G first to third tergites in dorsal view.