A new species of the genus Seticornuta Morley (Hymenoptera, Ichneumonidae, Metopiinae) from South Korea

Abstract Old World species of the genus Seticornuta Morley are reviewed. Seven species of this genus were recorded worldwide, but only one species, Seticornuta albopilosa (Cameron), was known from the Old World. Here, we report one new species, Seticornuta koreana sp. n., from South Korea, and redescribe the other known Old World species, Seticornuta albopilosa, with photographs.


Introduction
Seticornuta Morley is a rarely collected genus belonging to the subfamily Metopiinae. It is a small group, consisting of seven known extant species worldwide. Until now only one species, S. albopilosa (Cameron, 1907), has been recorded from the Oriental and Eastern Palaearctic regions. Seticornuta apicalis (Cresson, 1864) and S. terminalis (Ashmead, 1896) are only known to occur in North America, S. altamirae Gauld & Sithole, 2002 and S. cryptica Gauld & Sithole, 2002in Costa Rica, S. cortesi Porter, 1998 in Chile, and S. jacutinga Araujo & Penteado-Dias, 2012 from Brazil. In this study, we describe a new species, S. koreana Lee & Choi, sp. n., from South Korea. We also provide a redescription and photos of S. albopilosa, and a key to the Old World Seticornuta species.

Materials and methods
Materials used in this study were collected by sweeping and Malaise trapping, after which they were deposited in the animal systematic laboratory of Yeungnam University, Gyeongsan, South Korea (YNU). Specimens were examined using an AxioCam MRc5 camera attached to a stereo microscope (Zeiss SteREO Discovery. V20; Carl Zeiss, Göttingen, Germany), processed using AxioVision SE64 software (Carl Zeiss), and optimized with a Delta imaging system (i-solution, IMT i-Solution Inc. Vancouver, Canada) Measurements are reported for the holotype followed by variation in other specimens in brackets.
Abbreviations are as follows: NHM, The Natural History Museum, London, United Kingdom; ZSI, Zoological Survey of India, Calcutta, India; GG, Gyeonggido; CN, Chungcheongnam-do; GB, Gyeongsangbuk-do; GN, Gyeongsangnam-do. Diagnosis. Seticornuta species are moderate sized about 5-12 mm and generally blackish or black and yellow. Mandibles not twisted; labrum exposed when mandibles closed (Fig. 3A). Lower face moderately convex; upper face produced upwards into a small tooth between bases of antennae, but projection does not reach frons. Posterior part of head moderately to steeply declivous behind posterior ocelli (Fig. 3C, F). Propodeum moderately short, rather flat and more abruptly declivous posteriorly, with very strong median longitudinal carinae. Tergite I short with strong lateral and median longitudinal carinae. The New World genus Leurus is similar but the mandibles of Seticornuta species are slenderer and flanged (Gauld et al. 2002). New World species differ from Old World in their smaller size, lower number of antennal flagellomeres and the weakly concave apical margin of the clypeus.

Key to Old World species of the genus Seticornuta
1 Antennal scape and basal flagellomeres reddish brown (Figs 2, 3D-F). Line of combined face and mandible almost square (Fig. 3D). Mesoscutum rounded in lateral view (Fig. 3F). Areola and basal area not separated by carina (Fig.  3J). Spiracles of propodeum linear. Median longitudinal carinae convergent apically (Fig. 3J). Areolet of fore wing with short stalk (stalk shorter than vein 2rs-m; Fig. 3H Color. Black. Wings dark brown; front surfaces of fore tibia and tarsus as well as partial apical lower part of fore femur reddish brown. Morphology. Head. Face swollen, 1.3 times as long as wide in front view; head strongly narrowed behind eye in dorsal view. Occipital carina strong dorsally and laterally, obsolescent ventrally. Frons smooth with moderately coarse and dense punctures. Inner margin of eye indented a little above antennal socket. Diameter of lateral ocellus equal to shortest distance between ocellus and eye. Flagellum thickened in basal half, tapered to apex, with 47-50 flagellomeres. First flagellomere 1.4 times as long as wide, next flagellomere transverse, and last 6-7 flagellomeres square. Clypeus not separated from face. Combined face and clypeus almost square and lower part of gena below the eye rounded in frontal view (Fig. 3A, dotted line and arrow). Face very coarsely and densely punctate, with distance between punctures 0.3 times as long as their diameter, clypeus with more sparse punctures. Upper half of face strongly protruding in profile (Fig. 3C). Mandible except teeth with moderately dense and coarse punctures. Lower tooth of mandible shorter than upper tooth. Malar space 0.33 times as long as basal width of mandible.
Mesosoma. Flattened, 1.7 times as long as high in lateral view. Pronotum smooth, impunctate, protruding into an acute tooth laterally, in dorsal view (Fig. 3B, dotted line and arrow). Epomia weak. Mesoscutum elongate, with sparse punctures, anteriorly narrowly rounded in lateral view (Fig. 3C, dotted line and arrow), notaulus weak. Scutellum flat, without lateral carinae. Epicnemial carina strong, reaching subtegular ridge. Mesopleuron strongly swollen, with sparse punctures in front half. Submeta-pleural carina lobed. Metapleuron glabrous, impunctate, its lower front ridge strongly projecting as a tooth above mid coxa. Fore wing with petiolate areolet, length of stalk as long as 2rs-m. Hind outer angle of second discoidal cell sharp. Fore wing vein cu-a curved (Fig. 3G). Hind wing with 11 distal hamuli. Nervellus inclivous, intercepted distinctly below middle. Legs very stout. Hind femur coarsely punctate, 2.5 times as long as wide. Ratio between lengths of hind tarsomeres 63:21:18:11:20. Spurs of mid tibia of equal length. Tarsomeres 2-4 of fore leg shorter than wide. Longer spur of hind tibia 0.5 times as long as basitarsus. Propodeum with very strong median longitudinal and apical transverse carinae (Fig. 3I). Combined basal area and area superomedia with parallel sides. Basal area separated from area superomedia by weak carina in some specimens (Fig. 3I). Costula absent. Lateral area punctate except in anterior inner part. Propodeal spiracle 3.0 times as long as wide, joining pleural carina. Areolet of fore wing present, with stalk shorter than vein 2rs-m; fore wing vein cu-a curved (Fig. 3H). Hind wing with 11 distal hamuli. Nervellus inclivous, intercepted distinctly below middle. Legs very stout. Hind femur coarsely punctate, 3.0 times as long as wide. Spurs of mid leg with of equal length. Tarsomeres 2-4 of fore leg shorter than wide. Propodeum with very strong median longitudinal and apical transverse carinae. Combined basal area and area superomedia convergent apically. Basal area not separated from carina. Costula absent. Propodeal spiracle 3.7 times as long as wide, joining pleural carina.
Metasoma. Median dorsal carinae of first tergite very strong, extending to 2/3 its length. Second tergite 0.7 times as long as wide. Metasoma covered with rather long hairs.