Microrhagus mystagogus (Fleutiaux, 1923)

Seung, Jinbae & Lee, Seunghwan, 2018, Taxonomic review of genus Microrhagus Dejean, 1833 from Korea, with description of a new species (Coleoptera, Eucnemidae, Melasinae, Dirhagini), ZooKeys 781, pp. 81-95 : 81

Microrhagus mystagogus (Fleutiaux, 1923) Fig. 3

Dirhagus mystagogus Fleutiaux, 1923: 309.

Diagnosis.

Body: mostly dull black. Head: antennae pectinate from antennomere IV in male. Prothorax: pronotum convex, as long as wide; notosternal antennal grooves subparallel-sided. Pterothorax: elytra 2.3 × longer than combined width; metepisternum narrow, slightly widened posteriorly, its greatest width narrower than outer edge of metacoxal plate; metacoxal plate expanded inward; abdominal ventrite V simply rounded at apex.

Redescription.

Male (Fig. 3A, C–D) 3.2-3.9 mm long and 1.0-1.2 mm wide. Body mostly black; antennae and femur dark red-brown; tibiae and tarsi yellow-brown; surface weakly glossy, with yellow pubescence. Head with circular punctures, becoming denser and irregularly sized near frontoclypeal region; frons without carina or groove at midline; frontoclypeal region slightly depressed at base, rounded and weakly sinuate at anterior edge, anterior edge 3.9 × wider than distance between antennal sockets (Fig. 3G). Antennae (Fig. 3E) almost exceeding metacoxal plate, with yellow-brown pubescence, and pectinate from antennomere IV; processes of antennomeres IV, V, and VI 1.4, 2.3 and 2.6 × as long as corresponding antennomeres; antennomere I stout; antennomere II shortest; antennomere III gradually expanded toward apex, 1.9 × longer than wide, three × longer than II, and 1.8 × longer than IV; antennomeres IV–X with processes near apex, gradually lengthened toward apex; apical antennomere strongly elongate, curved, 11.5 × longer than wide, and 2.9 × longer than previous one. Pronotum as long as wide, parallel-sided; surface with more regularly sized and spaced punctures than on head, slightly larger and sparser posteriorly; disc with a short carina at base of midline; anterolateral carina short, almost reaching one-third length of pronotum; posterolateral carina exceeding two-thirds length of pronotum; antescutellar area almost straight; pronotal posterior angles sharply projecting, exceeding posterior edge of antescutellar area. Scutellum subtriangular, 1.1 × wider than long, gradually narrowed posteriorly, and rounded at apex; surface rough, barely pubescent. Elytra 2.3 × longer than combined width, parallel-sided, gradually narrowing near apices; disc barely striate, with shallow and irregularly sized and spaced punctures; several large and deep punctures present near apices; apices simply rounded. Prosternum subparallel-sided, anterior margin shallowly bisinuate; surface mostly with punctures as on pronotum, slightly larger laterally; prosternal process robust basally, abruptly tapered and curved dorsally at posterior end; hypomeron mostly punctate as prosternum; surface wrinkled at coxal cavities; notosternal antennal grooves (Fig. 3I) subparallel-sided, with outer marginal carina, rarely punctate, glabrous, and with pits. Mesoventrite with coarse surface; mesopleuron with irregularly sized and spaced punctures, especially anteriorly. Metaventrite mostly with finer punctures than on prosternum, slightly larger laterally; disc with a groove at midline, not reaching anterior margin; metepisternum (Fig. 3J) widened posteriorly, its greatest width four-fifths of outer edge of metacoxal plate; metacoxal plate (Fig. 3K) expanded inward, medially 1.8 × wider than laterally. Legs (Fig. 3O) slender; metatarsomere I 1.3 × longer than II–IV combined; metatarsomere II 1.3 × longer than III; metatarsomere V 1.2 × longer than II; claws simple. Abdomen with finer and denser punctures than on metaventrite; ventrite V simply rounded at apex (Fig. 3L). Aedeagus (Fig. 3 M–N) 3.9 × longer than wide, compressed dorsoventrally; median lobe slightly bent ventrally, fused with lateral lobes; lateral lobes strongly curved ventrally, enlarged near apex, densely setose; ventral lobe bifurcate apically, with dense short pubescence; phallobase strongly emarginate basally, 1.6 × longer than wide, approximately one-fifth as long as aedeagus. Female (Fig. 3B) is distinguished from male by following characters: body stouter, 3.4-3.9 mm long and 1.1-1.3 mm wide; frontoclypeal region (Fig. 3H) with anterior edge, 3.7 × wider than distance between antennal sockets; antennae (Fig. 3F) serrate, almost reaching metacoxal plate; antennomere III subrectangular, 3.1 × longer than wide, 2.3 × longer than II, and 1.6 × longer than IV; antennomeres IV–X gradually more strongly serrate; apical antennomere 3.5 × longer than wide, and approximately twice longer than X.

Specimens examined.

<Gyeonggi-do> 1♀, Deoksu-ri, Danwol-myeon, Yangpyeong-gun, N37°33'22.97", E127°41'13.65", 166m alt., flight intercept trap, 29 June– 16 July, 2016, Seung and Jung leg. (SNU). <Gangwon-do> 1♀, Yeongheung-ri, Yeongwol-eup, Yeongwol-gun, N37°12'19.84", E128°27'17.77", 308m alt., flight intercept trap, 19 June– 02 July, 2015, Seung and Lee leg. (SNU); 1♂, Beopheung-ri, Suju-myeon, Yeongwol-gun, N37°22'41.19", E128°15'15.50", 550m alt., flight intercept trap, 03-16 July. 2015, Seung and Lee leg. (SNU); 1♂2♀, Beopheung-ri, Suju-myeon, Yeongwol-gun, N37°22'41.19", E128°15'15.50", 550m alt., flight intercept trap, 05-29 June, 2016, Seung and Jung leg. (SNU).

Distribution.

Korea (New record), Japan, Russia (Far East).

Remarks.

Microrhagus mystagogus is easily distinguished from other Korean Microrhagus species by its antennae: male antennae pectinate from antennomere IV. Also, convex pronotum and structure of aedeagus are characteristic. Its aedeagal structure is well-illustrated in Kovalev’s (2013) work.