Microrhagus ramosus Fleutiaux, 1902

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 ramosus Fleutiaux, 1902 Fig. 4

Microrhagus ramosus Fleutiaux, 1902: 24.

Diagnosis.

Body: mostly weakly shiny black. Head: frons with a weak carina at midline; antennae pectinate from antennomere III in male. Prothorax: pronotum with dense punctures, average distance between punctures smaller than puncture diameter, disc with paired dimples at middle; notosternal antennal grooves slightly expanded posteriorly. Pterothorax: elytra 2.2 × longer than combined width; metepisternum gradually widened posteriorly, its greatest width wider than outer edge of metacoxal plate; metacoxal plate expanded inward. Abdomen: abdominal ventrite V weakly narrowly rounded at apex.

Redescription.

Male (Fig. 4A, C, D) 3.3-4.8 mm long and 1.0-1.5 mm wide. Body mostly black; antennal branches and tibiae orange-brown; tarsi yellow-brown; surface weakly glossy, with yellow pubescence. Head regularly sized, circular punctures, becoming finer and denser near frontoclypeal region; frons with a weak carina at midline; frontoclypeal region slightly depressed at base, weakly sinuate at anterior edge, anterior edge 4.2 × wider than distance between antennal sockets (Fig. 4G). Antennae (Fig. 4E) almost exceeding metacoxal plate, with yellow-brown pubescence, pectinate from antennomere III; processes of antennomeres III, IV, and V 1.4, 2.5, and 2.4 × as long as corresponding antennomeres; antennomere I robust; antennomere II shortest; antennomere III with process near base, 1.7 × longer than II, and 1.3 × longer than IV; antennomere IV with process at mid-length; antennomeres V–X with processes near apex, gradually lengthened and narrowing toward apex; apical antennomere strongly elongate, curved, 9.4 × longer than wide, and 2.2 × longer than X. Pronotum 1.1 × wider than long, subparallel-sided near base, gradually narrowed anteriorly from basal two-thirds; surface mostly with denser punctures than on head, average distance between punctures smaller than puncture diameter; disc with paired dimples at middle and a short carina at base of midline, and symmetrically depressed near base; anterolateral carina almost reaching pronotal mid-length; posterolateral carina almost exceeding pronotal mid-length, fused with anterolateral carina in some; antescutellar area weakly notched in dorsal view; pronotal posterior angles sharply projecting, exceeding posterior edge of antescutellar area. Scutellum raised; triangular, 1.3 × longer than wide, gradually narrowed posteriorly, and rounded at apex; surface rough, densely pubescent, especially near apex. Elytra 2.2 × longer than combined width, subparallel-sided, gradually narrowed posteriorly; disc weakly striate, with irregularly sized and spaced punctures; interstriae slightly convex, with several large and deep punctures near apices; apices simply rounded. Prosternum with curved sides, anterior margin slightly bisinuate; surface with more scattered and regularly sized punctures than on pronotum; prosternal process stout, gradually tapered and curved dorsally at posterior end; hypomeron with denser, and larger punctures than on prosternum; notosternal antennal grooves (Fig. 4I) slightly widened posteriorly, barely punctate, glabrous, and with pits. Mesoventrite with coarse surface, with irregularly sized and spaced punctures; mesopleuron with rough surface, especially anteriorly. Metaventrite with finer and sparser punctures than on prosternum, especially at middle; disc with a weak groove at midline, not reaching anterior margin; metepisternum (Fig. 4J) gradually widened posteriorly, its greatest width 1.2 × wider than outer edge of metacoxal plate; metacoxal plate (Fig. 4K) expanded inward, medially 2.3 × wider than laterally. Legs (Fig. 4O) slender; metatarsomere I 1.3 × longer than II–IV combined; metatarsomere II 1.3 × longer than III; metatarsomere V 1.5 × longer than II; claws simple. Abdomen punctate as metaventrite; ventrite V narrowly rounded at apex (Fig. 4L). Aedeagus (Fig. 4 M–N) five × longer than wide; median lobe slightly curved ventrally, deeply bifurcate at apex; lateral lobes as long as median lobe, subparallel-sided, curved ventrally, with basally attached secondary lateral lobes; secondary lateral lobes parallel-sided, curved ventrally, pointed at apex; ventral lobe shorter than median lobe, parallel-sided, truncate at apex, and densely pubescent; phallobase rectangular, 1.6 × longer than wide, almost one-third of entire length of aedeagus. Female (Fig. 4B) is distinguished from male by following characters: frontoclypeal region with anterior edge, four × longer than distance between antennal sockets (Fig. 4H); antennae (Fig. 4F) serrate, not reaching metacoxal plate; antennomere I stout; antennomere II short, as long as IV; antennomere III 1.9 × longer than wide, 1.7 × longer than IV; antennomere IV–X gradually lengthened, narrowing and more strongly toothed toward antennal apex; apical antennomere elongate, 3.5 × longer than wide, 2.2 × longer than previous one.

Specimens examined.

<Gangwon-do> 3♂1♀, Beopheung-ri, Suju-myeon, Yeongwol-gun, N37°22'41.19", E128°15'15.50", 550m alt., flight intercept trap, 19 June– 02 July, 2015, Seung and Lee leg. (SNU); 2♂1♀, Deokgu-ri, Sangdong-eup, Yeongwol-gun, N37°5'34.46", E128°48'59.53", 648m alt., flight intercept trap, 19 June– 02 July 2015, Seung and Lee leg. (SNU); 3♂, Deokgu-ri, Sangdong-eup, Yeongwol-gun, N37°5'34.46", E128°48'59.53", 648m alt., flight intercept trap, 02-16 July, 2015, Seung and Lee leg. (SNU); 5♂, Hoenggye-ri, Daegwanryeong-myeon, Pyeongchang-gun, N37°40'58.95", E128°45'21.80", 830m alt., flight intercept trap, 05-29 June, 2016, Seung and Jung leg. (SNU); 1♂, Jindong-ri, Girin-myeon, Inje-gun, N37°58'11.10", E128°24'23.97", 619m alt., 13 July, 2016, M. S. Oh leg. (SNU). <Jeollanam-do> 1♂, Donggok-ri, Ongnyong-myeon, Gwangyang-si, N35°5'13.37", E127°36'48.93", 577m alt., flight intercept trap, 04-15 July, 2016, Seung and Lee leg. (SNU). <Jeju Is.> 1♂, Gyorae gotjawal, Gyorae-ri, Jocheon-eup, Jeju-si, N33°26'21.15", E126°40'12.75", 428m alt., flight intercept trap, 13 May– 10 June, 2016, Seung and Jung leg. (SNU); 1♂, Seongpanak, Gyorae-ri, Jocheon-eup, Jeju-si, N33°23'10.82", E126°37'13.77", 752m alt., flight intercept trap, 13 May– 10 June, 2016, Seung and Jung leg. (SNU).

Distribution.

Korea, Japan.

Remarks.

Microrhagus ramosus shows morphological variation as below: pronotal anterolateral carina and posterolateral carina obscure in some, appearing fused in some; ventral lobe of aedeagus sub-parallel sided in some, slightly widened near apex.