Orthocentrus brachycerus 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

2 . Orthocentrus brachycerus Humala & Lee sp. nov.

Fig. 2

Description.

Female. Fore wing length 3.0-3.5 mm.

Face at level of antennal sockets 1.4 times as wide as high; face smooth, polished, sparsely and slightly punctate; eyes not setose; dorsal ridge of face in between antennal sockets with a median blunt low prominence; face profile straight except dorsally very slightly impressed; inner eye orbits slightly divergent ventrally; edge of clypeus straight; antennal sockets not on a distinct high shelf; subocular sulcus distinct, sharp, slightly bent towards occiput; maxillary palp reaching fore coxa. In dorsal view, head posteriorly concave, temples short; lateral ocellus separated from eye by its maximum diameter; POL 1.8 times as long as diameter of lateral ocellus; ocellar-ocular grooves present. Minimum distance between antennal sockets about 0.4 × diameter of socket; antenna very short, with 19 flagellomeres (n = 15) gradually shortening towards apex of antenna; basal flagellomere 1.5 times as long as wide and about 0.4 × of length of scape; scape slightly convex on inner surface, slightly concave on outer surface.

Mesosoma polished; mesoscutum anteriorly with distinct notauli; in profile, scutellum weakly convex, metapleuron slightly convex; propodeum with posterior transverse carina complete, strong and raised between lateral longitudinal carinae, lateromedian longitudinal carinae complete, lateral longitudinal carinae distinct, propodeal spiracle small.

Legs robust; coxae polished, femora with coriaceous microsculpture, tibiae and tarsi coriaceous-granulate; hind femur 3.0 times as long as high, hind tibia 4.0 times as long as apically wide, with spine-like setae.

Wings not particularly narrow; fore wing without areolet; vein Rs nearly straight; vein Rs+2r meeting pterostigma at basal 0.45; vein cu-a opposite Rs&M; nervellus intercepted in lower third.

First tergite slightly widening posteriorly, 1.2 times as long as apically wide; coriaceous, with two distinct lateromedian longitudinal carinae and indistinct longitudinal striae, with transverse impressions originating at about middle of tergite, sloping posteriorly, meeting centrally.

Second tergite 0.9 times as long as posteriorly wide; coriaceous and longitudinally striate, sometimes with lateromedian longitudinal carinae in anterior half, anterior corners impressed and transverse groove near posterior margin bending anteriorly near lateral margins, forming a somewhat uplifted area medially with longitudinal striae; thyridia rounded. Third tergite with coriaceous microsculpture anteriorly; remainder of metasoma unsculptured, polished. Ovipositor thin, slightly upcurved, without subapical dorsal notch; ovipositor sheath narrow, with sparse setae.

Body setose except eyes, pronotum, mesopleuron and metapleuron; setae scattered on metasoma and posterior sides of coxae.

Blackish brown; face yellow, sometimes laterally infuscate; inner orbits broadly whitish-yellow up to occiput; antenna orange; malar area yellow posterior to malar sulcus and up to level of lower third of eye; mouthparts, fore and mid coxae, all trochanters and trochantelli yellowish creamy, remainder of fore and mid legs yellow; hind legs orange, posterior margins of tergites 1-4 brown. Sometimes lower mesopleuron and scutellum reddish-brown.

Male. Flagellum with 21 flagellomeres; face and frontal orbits yellow. Otherwise as in female.

Biology.

Hosts unknown.

Etymology.

Named from the Greek βραχύς (short) and κέρας (horn) after the short antenna.

Comparison.

Compared with the other species that have lenticular head, flattened and smooth face, short temples, and eyes glabrous, the fore wing areolet is absent and the flagellum with fewer than 20 flagellomeres, unlike in O. koreanus and O. consobrinus . From the allied O. leei it differs in the yellow face and frontal orbits up to the level of the lateral ocelli; the POL 1.8 times as long as diameter of an ocellus.

Material examined.

Holotype: female; South Korea, GB: Daegu-si , Dalseo-gu , Daegok-dong, Daegusumogwon, 35°48'3.26"N, 128°31'15.3"E, 27.VII-8.VIII.2011, J.W. Lee leg. (DNUE-0496).

Paratypes: South Korea, GB: 1♀, Daegu-si, Dalseo-gu, Daegok-dong , Daegu Arboretum , 88 m, 35°47'38.6"N, 128°31'33.5"E, 4-18.IV.2012, S.G. Kang leg. (DNUE-0120); 1 ♂, Bongjeongsa 10-11.VII.1998, J.W. Lee leg. (DNUE-0135); GG: 3 ♀, Pocheon-si, Soheul-eup, Jikdong-ri, Korean National Arboretum, Gwangeung Forest , MTII, 123 m, 37°45'22"N, 127°9'48.9"E, MT, 15.VII-2.VIII.2013, S.Y. Park, J.O. Lim & J.S. Lim leg. (DNUE); 1♀, Pocheon-si, Soheul-eup, Jikdong-ri, Korean National Arboretum, Gwangeung Forest , MTII, 120 m, 37°45'22"N, 127°9'48.9"E, MT, 28.VI-15.VII.2013, S.Y. Park, J.O. Lim & J.S. Lim leg. (ZIN); 1♂, Schihung-si, Mt. Chongsu , 22.VIII.1988 J.W. Lee leg. (DNUE-0481); GN: 1♀, Dapcheon-ri, Ibanseong-myeon, Jinju-si, MTIII, 27.VI-4.VII.2005, B.K. Ahn leg. (ZIN-0376); GW: 2♀, Chuncheon-si, Sanong-dong, Gwangwon Provincial Arboretum, 30.VIII-17.IX.2013, I.G. Kim leg. (DNUE); 2♀, Chuncheon-si, Sanong-dong, Gwangwon Provincial Arboretum, 17.VII-1.VIII-2013, I.G. Kim leg. (DNUE); 1♀, Heungeop-myeon, Maeji-ri, Yeosedae gyonae ungoleong yeop, 37°16'53"N, 127°54'02"E, MT, 19.V-6.VI.2011, J.W. Lee leg. (DNUE-0243); JB: 2♀, Wanju-gun, Dongsang-myeon, Daea-ri, San 1-2, Daea, 35°58'24.24"N, 127°18'13.53"E, MT, 16-31.VIII.2013, J.M. Park leg (DNUE); 1♀, Iksansi Sinyongdong, Wongwang University, 35°57'N, 126°57'E, MT, 21.VII-17.VIII.2006, J.W. Lee leg. (ZIN-0253); JN: 1♀, Kwangju-si Buk-gu, Geumgok-dong, Mudeungsan National Park , Wonhyosa, 35°57'N, 126°57'E, MT, 26.VI-27.VII.2013, J.K. Choi leg. (ZIN-0108) .

Distribution.

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

Figures

Figure 2. Orthocentrus brachycerus sp. nov. Holotype. A Habitus in lateral view B head in frontal view C head and mesosoma in lateral view D head in dorsal view E scutellum and propodeum in dorsal view F first and second tergites in dorsal view.