Omalium septentrionis Thomson, 1857

Shavrin, Alexey V., 2025, Review of the genus Omalium Gravenhorst, 1802 (Coleoptera: Staphylinidae: Omaliinae: Omaliini) of Siberia and Far Eastern Russia, with notes on some species from Mongolia and Japan, Zootaxa 5646 (2), pp. 199-235 : 210-212

3.2.3.2. Omalium septentrionis Thomson, 1857

( Fig. 22 )

Omalium septentrionis Thomson, 1857: 223 .

Ochtchexenus clavicorne Motschulsky, 1860: 546 .

Homalium clavatum Fauvel, 1869: 493 (replacement name for O. clavicorne Motsch. ).

Homalium languidum Mäklin, 1878: 29 .

For other references see Herman (2001a).

Material examined. RUSSIA: TYUMEN AREA: 1 ♀: Uvatskiy District, 10 km S Gornoslinkino, near Tobolsk Field Research Station of Severtsov Institute. In gill and geophilous fungi. 10.09.2003. A.B. Ryvkin leg. (cSh); KHANTY-MANSI AUTONOMOUS REGION: 2 ♂♂, 1 ♀: Surgutskiy District, near Ugut vill., basin of Ugutka River . In geophilous fungi. 20.08.1998. A.B. Ryvkin leg. (cR); 1 ♀: same District, Yuganskiy Reserve, 3–5 км SW cordon at Kol-Kochen-Yagun River . In gill fungi ( Pholiota , different small fungi and very old dried Armillaria ). 13.09.1999. A.B. Ryvkin leg. (cSh); 1 ♀: same District, Yuganskiy Nature Reserve, Basin of Ay-Magromsy River , “Medvezhiy Ugol” cordon. In geophilous and gill fungi, in mosses and litter under those (+6 C). 14.09.2002. A.B. Ryvkin leg. (ZMM); TAIMYR AUTONOMOUS REGION: 1 ♀: Khatangskiy District, Taimyrskiy Biosphere Reserve, Ary-Mas : right bank of Novayaver , 1 km up-stream of field research station. Bank of Novaya River : sand, silt, river sediments between Salix spp. , Carex spp. , grasses, etc. A.B. Ryvkin leg. (ZMM); KRASNOYARSK AREA: 1 ♂: Yeloguy Nature Refuge, Yeloguy River, 6 km below mouth of Tyna River . In mosses and litter at swampy bank of stream with Betula , Alnus , Sphagnum sp. 24.07.1992. V.B. Semenov leg. (ZMM); 1 ♀: same data, on polypores growing on Betula and in litter under those. 24– 31.07.1992 (ZMM); 1 ♀: Turukhanskiy District, Central Siberian State Reserve, near Lebed` vill. 40 m a.s.l., clay and silty bank of Verknyaya Lebedyanka River near mouth ( Salix , Alnus , Urtica , few grasses, Equisetum , Filipendula , Geranium etc.). 23.06.1989. A.B. Ryvkin leg. (ZMM); 4 ♀♀: same Reserve, Stolbovaya River basin: lower reaches of Birapchana River near mouth of Kruten`kiy Stream. 110 m a.s.l., river bank with Salix sp. , dead Poaceae gen. spp., etc., in drift. 23.06.1993. V.B. Semenov leg. (ZMM); 2 ♂♂: same District, Bor. 40 m a.s.l., evening flying. 13.05.1992. V.B. Semenov leg. (cR); 1 ♂: same data, Betula forest, in Pleurozium with dog excrements. 14.06.1992. (cR); 1 ♂: same District, Mirnoye. Floodplain spruce forest. 16.07.1978. K.Yu. Es`kov leg. (ZMM); 1 ♀: same District, Nizhnyaya Sarchikha River near mouth of Kamenka River . 150–200 m a.s.l., mosses amd litter in forest with Betula , Abies , Pinus sylvestris , P. sibirica , Juniperus , Vaccinium myrtillus , Pleurozium , Hylocomium , Polytrichum commune . 10.07.1992. V.B. Semenov leg. (cSh); 1 ♀: ‘ Jeniseisk 58º20’’, ‘septentrionis Thoms. ’, ‘2686’, ‘7202 E91+’ (SMNH); 1 ♂: ‘ Vorogovo 61º’, ‘ Sibir Jeniseie’ , ‘2599’, ‘7203 E91+’ (SMNH); 1 ♀: ‘ Worog Selo’, ‘ Sibir Jeniseie’ , ‘ Ndsk & Stbg’, ‘languidum Mäklin’, ‘7204 E91+’ (SMNH); 1 ♀: ‘ Worog Selo’, ‘ Sibir Jeniseie’ , ‘ Ndsk & Stbg’, ‘languidum var.? ♀ ’, ‘(H. binotatum)+’, ‘72051 E91+’, ‘septentrionis Thoms. ’ (SMNH); EVENKIA: 1 ♀: Baykitskiy District, Central Siberian Biosphere Reserve, Podkamennaya Tunguska River , mouth of Stolbovaya River . 50 m a.s.l., in gill and arboreal fungi. 11.09.1988. A.B. Ryvkin leg. (cR); 5 ♂♂, 7 ♀♀: same District, basin of Podkamennaya Tunguska River, environs of Kuz`movka, near Kuz`movskiy Stream. Rotten gill fungi and litter under those. 12.08.1989. A.B. Ryvkin leg. (cR, cSh); TUVA: 1 ♀: Todzhenskiy District, Azas State Reserve, Aas River between mouth of Kara-Tesh and Kadyrgy-Sug rivers. 980 m a.s.l., in litter of nest of Castor fiber (wood chips). 07.06.1990. A.B. Ryvkin leg. (cSh); 1 ♂: same data, Toora-Khem vill. 900 m a.s.l., day and evening flying in the yard and at bank of Toora-Khem River . 05.06.1992. A.B. Ryvkin leg. (cR); IRKUTSK AREA: 1 ♀: Bodaibinskiy District, Vitimskiy Nature Reserve, first right tributary of Pravaya Polovinka River , 57°07’25.6’’N 116°35’58.3’’. 829 m a.s.l., wet Sphagnum sp. between stones near bank of the river. 13.07.2016. I.V. Enushchenko leg. (cSh); 1 ♀: Irkutsk District, Angarsk, Yelovskoye water reservoir. 29.08.2010. I.V. Enushchenko leg. (cSh); 1 ♂, 1 ♀: Irkutsk, left side of Angara Rver, Akademgorodok , 52°14’48.1’’N 104°15’13.4’’E. 518 m a.s.l., in rotten Pluteus sp. 17.07.2013. I.V. Enushchenko leg. (cSh); 8 ♂♂, 1 ♀: same data, on Pluteus cervinus . 09.07.2018. (cSh); 1 ♂: same data. Evening flying. 14.04.2025. (cE); 2 ♂♂: ‘Irkutsk leg. Bokor’, ‘Coll. Dr. J. Fodor’ (HNHM); 1 ♂: Irkutsk. 21.08.1982. V.G. Shilenkov leg. (cR); 1 ♂, 1 ♀: Shelekhovskiy District, Shelekhov. In mushrooms. 09.1992. A.V. Shavrin leg. (cSh); AMUR AREA: 1 ♂, 1 ♀: Selemdzhinskiy District, Byssa River basin NW of “Tyoplyi Klyuch” spa. 300 m a.s.l., mosses and litter in afforested tussocks at depression: Carex spp. , Poaceae gen. spp., Polytrichum commune , Salix spp. , Alnus sp. , Rosa sp. , Spiraea spp. , etc. 21.06.2007. E.M. Veselova & A.B. Ryvkin leg. (ZMM); 1 ♀: same District, Norskiy Reserve, Nora River basin, 1.5–2 km up-stream of Gryashchinskaya Mt. , 235 m a.s.l., between hut and lake, in sparse burnt birch-aspen-larch forest, under? Pleurotus sp. + fungus #8 on high birch stub. 10.09.2008. E.M. Veselova & A.B. Ryvkin leg. (ZMM); KHABAROVSK TERRITORY: 1 ♂: Verkhnebureinskiy District, near Niman cordon of Bureinskiy Nature Reserve , N 52°08.48’ N 134°13.54’ E. 1035 m a.s.l., mushroom bait (flotation). 18.08.2008. A.B. Ryvkin leg. (ZMM); 3 ♂♂: same District, lower reaches of Verkhniy Mel’gin River near 1st rapid. 300–350 m a.s.l., in geophilous fungi. 18.08.2009. A.B. Ryvkin leg. (cR); 1 ♀: Verkhnebureinskiy District, Dublikanskiy Nature Refuge, Orodzhimen Stream 1 km up-stream of mouth. 370 m a.s.l., mosses and litter under Alnus sp. , Salix spp. , Larix gmelinii, Betula spp., Picea ajanensis , Abies nephrolepis , with Poaceae gen. spp., Filipendula palmata , Spiraea spp. , Sorbaria sorbifolia , Carex spp. , Plagiomnium sp. , Sphagnum spp. , Hylocomium splendens , etc. 04.09.2009. A.B. Ryvkin leg. (cSh); MARITIME PROVINCE: 1 ♀: Lazovskiy Nature Reserve , 2 km W Lazo. 28.06.2007. A.V. Shavrin leg. (cSh).

Remarks. The Palaearctic O. septentrionis ( Fig. 22 ) is one of the common species in Siberia and Far Eastern Russia. It was recorded from Sverdlovsk ( Ermakov et al. 2017) and Tyumen (J. Sahlberg 1880) areas, Krasnoyarsk Territory (J. Sahlberg 1880; see studied material above), Irkutsk Area ( Shavrin et al. 1999: 28, Shavrin 2001, 2009, 2010), Buryatia ( Eppelsheim 1893), Chita ( Shavrin 2010) and Magadan ( Ryabukhin 1999) areas, and Maritime Province ( Filatova 1968).

It is here recorded from Khanty-Mansi and Taimyr autonomous regions, Evenkia, Tuva, Amur Area and Khabarovsk Territory for the first time.

Figures

FIGURES 22–24. Habitus of Omalium: 22—O. septentrionis (Russia: TyumenArea, Ugut), 23—O. curtipenne (Russia: Irkutsk Area, Vitim Nature Reserve), 24—O. diffine (holotype). Scale bar: 1.0 mm.