Lathrobium oharai WATANABE, 2004

Assing, Volker, 2015, New species and additional records of Lathrobium and Elytrobium from the Palaearctic region, with special reference to the fauna of East Yunnan (Coleoptera: Staphylinidae: Paederinae), Beiträge Zur Entomologie = Contributions to Entomology 65 (1), pp. 41-74 : 67-69

Lathrobium oharai WATANABE, 2004

( Figs 111–118 )

Material examined: Japan: Hokkaido: 4 , 3 , Kushiro marsh, between Horo and Oshima rivers, 5 m, 31.VII.1991, leg. Smetana [J21] ( CNC, cAss); 2 , Sapporo, Nakayama Pass, 800 m, 26.VII.1991, leg. Smetana [J8] ( CNC); 1 , 1 , Shiretoko Peninsula, Rausu, Rausu Lake Trail, 720 m, 1.VIII.1991, leg. Smetana [J24] ( CNC, cAss); 2 , 1 , Horokanai, Butokamabetsu river , 430 m, 3.VIII.1991, leg. Smetana [J29] ( CNC, cAss); 1 , same data, but 300 [J31] ( CNC); 1 , 1 , Horokanai, Dorogawa, 280–300 m, 5.VIII.1991, leg. Smetana [J34] ( CNC) . Russia: Sakhalin: 1 ex., Aniva district, Zuneyiskiy mountains, 10 km N Novo Aleksandrovsk, Mt. Tshekhov , 1000 m, 13.VII.1993, leg. Pütz & Wrase (cSch); 1 ex., Aniva district , Kamiyshoviye mountains , Levedskiy pass, 30 km NW Aniva, 700–800 m, 14.VII.1993, leg. Pütz & Wrase (cSch); 1 ex., Aniva district , 5 km W Petropavlovskoye, tributary of Lyutoga river , 20.–21.VII.1993, leg. Pütz & Wrase (cSch); 1 ex., Aniva district , Ogonoki near Yuzhno-Sakhalinsk, 29.VI.1992, leg. Basarukin (cSch). (The material from Sakhalin was identified and communicated by M. Schülke.) .

Comment: The original description is based on three type specimens from “Urup, Kuril Arch. Russia, ..., 45°39.04'N, 149°28.78'E " ( WATANABE 2004). The phylogenetic affiliations of this species are somewhat unclear. It is characterized particularly by the conspicuously oblong and posteriorly tapering head, the nearly unmodified male sternite VII, and by the absence of micropubescence on the female sternite VIII. WATANABE (2004) suggests that L. oharai is closely allied to L. japonicum , whose head is oblong, too (though much less so than in L. oharai ). However, in L. japonicum the shapes and chaetotaxy of the male sternites VII and VIII are distinctly modified, and the female sternite VIII has micropubescence. According to a recent study ( ASSING 2013e), the presence of micropubescence in the posterior portion of the female sternite VIII is one of the characters separating Lathrobium from other closely related genera within the Lathrobiina.

Redescription: Body length 7.0–9.0 mm; length of forebody 4.0– 4.5 mm. Habitus as in Fig. 111 . Coloration: body blackish; legs and antennae dark-reddish to darkbrown.

Head ( Fig. 112 ) conspicuously oblong, 1.15–1.20 times as long as broad, tapering posteriorly; posterior angles almost obsolete; punctation rather coarse and dense, somewhat sparser in median dorsal portion; interstices with pronounced microreticulation and subdued shine. Eyes slightly less than one-third as long as distance from posterior margin of eye to posterior constriction of head in dorsal view and composed of numerous small ommatidia. Antenna 2.2–2.4 mm long.

Pronotum ( Fig. 112 ) approximately 1.2 times as long as broad and about 1.05 times as broad as head; punctation similar to that of head; impunctate midline moderately broad; interstices without microsculpture.

Elytra ( Fig. 112 ) moderately short, approximately 0.8 times as long as pronotum, weakly dilated posteriad; humeral angles weakly marked; punctation shallow and moderately dense; interstices without microsculpture. Hind wings reduced. Protarsomeres I–IV distinctly dilated, without evident sexual dimorphism.

Abdomen as broad as, or slightly broader than elytra; punctation moderately fine and rather dense, nearly as dense on tergite VII as on anterior tergites; interstices with very shallow microsculpture; posterior margin of tergite VII with palisade fringe; tergite VIII with weakly convex posterior margin.

: sternite VII ( Fig. 113 ) moderately strongly transverse, with weakly concave posterior margin, but without other modifications; sternite VIII ( Fig. 114 ) transverse, with very small posterior excision; aedeagus ( Figs 115–116 ) approximately 1.3 mm long and symmetric; ventral process apically strongly narrowed apically in ventral view and bisinuate in lateral view; dorsal plate with moderately long, moderately sclerotized, plate-shaped, and apically acute apical portion, and with short and very thin basal portion; internal sac without sclerotized structures.

: sternite VIII ( Fig. 117 ) approximately as broad as long and with broadly convex posterior margin, without micropubescence in posterior portion; tergite IX ( Fig. 118 ) with undivided antero-median portion; tergite X ( Fig. 119 ) flattened and of broadly oval shape, approximately as long as antero-median portion of tergite IX.

Distribution and natural history: The known distribution of L. oharai is confined to the Kuril Islands and Hokkaido, but it does not seem unlikely that it is present also in Sakhalin and/or mainland Russia. The palisade fringe at the posterior margin of the abdominal tergite VII is still present, suggesting that the species may be wing-dimorphic. The above specimens from Hokkaido represent the first records from Japan. They were collected at altitudes of 5– 800 m.

Figures

Figs 111–125: Lathrobium oharai WATANABE and L. scaphiforme spec. nov. (119–125) habitus (111–119); forebody (112, 120); male sternite VII (113, 121); male sternite VIII (114, 122); aedeagus in lateral and in ventral view (115–116, 123–124); female sternite VIII (117); female tergites IX–X (118); apical portion of aedeagus in dorsal view (125). Scale bars: 111–112, 119–120: 1.0 mm; 113–118, 121–125: 0.5 mm.