taxonID	type	description	language	source
F91B87958332BC448BE097110969FEF0.taxon	description	(Figs 1, 4 – 5, 17, 20)	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958332BC448BE097110969FEF0.taxon	materials_examined	Type material examined. Holotype ♂ (Fig. 1; dissected prior to the present study): ‘ Shangai | Leder 1892. ’ <handwritten in black>, ‘ sulcifrons Epp | Norde Mongol. ’ <handwritten in black>, ‘ c. Eppelsh. | Steind. d. ’ <printed>, ‘ longicorne m. [handwritten in black] | Type. [handwritten in black] | det. Luze [underlined] ’ <printed>, ‘ TYPUS’ <red, printed>, ‘ Omalium | longicorne Luze, 1906 | Shavrin A. V. det. 2025 ’ <printed> (NMW). Material examined. RUSSIA: AMUR AREA: 1 ♂: Selemdzhinskiy District, Norskiy Nature Reserve, Nora River basin near Meunskiy cordon. 260 m a. s. l., mosses, leaf litter, plant debris among Carex tussocks and under Spiraea spp. and Vaccinium uliginosum near small frozen rill on mari near foot of SE slope of Ust’ - Meunskaya Mt. 21.09.2008. E. M. Veselova & A. B. Ryvkin leg. (cSh).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958332BC448BE097110969FEF0.taxon	description	Redescription. Measurements (n = 4): HW: 0.53 – 0.62; HL: 0.41 – 0.47; OL: 0.17 – 0.18; TL: 0.07; AL (holotype): 1.40; PL: 0.47 – 0.57; PWmax: 0.65 – 0.75; PWmin: 0.57 – 0.71; ESL: 0.88 – 1.07; EW: 0.81 – 1.07; MTbL (holotype): 0.57; MTrL (holotype): 0.27 (MTrL 1 – 4: 0.12; MTrL 5: 0.15); AW: 0.90 – 1.20; AedL: 0.68 – 0.81; BL: 3.06 – 4.10 (holotype: 3.80). Habitus as in Fig. 1. Body yellowish-brown to reddish-brown, with paler lateral and basal parts of pronotum and elytra in two specimens; maxillary palpomeres and antennae brown, with paler antennomeres 1 – 4; mouthparts, legs and paratergites yellow-brown (tarsi slightly paler). Punctation of head dense, moderately coarse and deep, denser in middle, slightly sparser between anteocellar foveae, finer and sparser on posterior parts of infraorbital portions; neck with sparse or dense, moderately fine punctation; punctation of pronotum dense and relatively fine, sparser in medioapical and mediobasal (holotype) or in middle portions, sparser in lateroapical and usually larger in laterobasal portions; scutellum without punctures; punctation of elytra dense, about as that on pronotum, but slightly larger and deeper, finer and sparser around scutellum and along suture and denser, coarser in lateral and apical portions; abdominal tergites with indisinct, sparse and fine punctation. Anterior portion of clypeus with distinct transverse microsculpture, laterobasal parts of clypeus with traces of fine longitudinal meshes, middle portion without or with fine subdiagonal microreticulation, each mediodorsal part of infraorbital portion near eye with fine longitudinal meshes; medioapical part of neck without or with fine transverse microsculpture; pronotum and elytra without sculpture; scutellum with fine indistinct isodiametric or transverse meshes; abdominal tergites with dense transverse or isodiametric microreticulation. Anterior portion of clypeus with several erect and moderately long setae (specimen from Amur Area with additional long erect setae in each mediolateral part of clypeus and mediobasal part of infraorbital portion); lateral portions of pronotum with several short suberect setae; abdominal tergites with fine, sparse and short setation; posterior margin of pronotum with row of very short cuticular fringe visible in the holotype. Head 1.2 – 1.3 times as broad as long, somewhat flattened or slightly elevated in middle, with relatively broad clypeus and strongly convex and slightly explanate supra-antennal elevations, and with shallow to moderately deep and wide elongate anteriomedian depressions, reaching about level of anterior third of eyes; each posteriolateral margin of clypeus diagonally stretching posteriad toward level of middle or posterior third of eye. Mediodorsal surface with distinct diagonal elevations on lateral portions of clypeus, with elongate narrow elevation (indistinct in holotype) along each infraorbital portion near margin of eye and several shorter indistinct wrinkles between it and mediodorsal margin of eye. Anteocellar foveae short, suboval or slightly elogate, very deep, not or slightly convergent latero-apicad toward level of posterior third of eyes. Temples moderately convex, more than twice as long as longitudinal length of eye, gradually narrowed posteriad. Nuchal constriction present, narrow but moderately deep. Eyes large and convex. Ocelli moderately small, indistinct, located significantly behind level of posterior margins of eye; distance between ocelli short, more than one and a half times as long as distance between ocellus and posterior margin of eye. Maxillary palpi moderately long, palpomere 4 (apical) slightly more than three times as long as slightly elongate penultimate segment, from widest middle gradually narrowed toward subacute apex. Antenna reaching basal portion of elytra when reclined, with distinctly elongate antennomeres, gradually broadened apicad; basal antennomere wide and robust, about three times as long as broad, antennomere 2 about twice shorter and narrower than basal segment, 3 slightly narrower and distinctly longer than 2, 4 – 5 shorter than 3, 6 – 7 slightly longer and broader than 5, 8 – 10 distinctly broader than 7, apical antennomere slightly longer than preceding segment, from about middle gradually narrowed toward rounded or subacute apex. Pronotum slightly convex, 1.3 times as broad as long, 1.2 times as broad as head, from widest middle gradually narrowed both anteriad and posteriad or slightly more narrowed posteriad toward obtuse hind angles. Apical angles broadely widened, not or indistinctly protruded anteriad. Anterior margin straight or slightly rounded, distinctly shorter than slightly rounded posterior margin. Lateral portions narrowly margined, slightly explanate in lateroapical portion, each with deep and wide elongate impressions slightly behind middle. Surface of disc with two elongate, shallow or moderately deep longitudinal depressions, significantly broadened basad, with small and shallow medioapical depression; each lateroapical portion with curved narrow elevation (invisible in holotype), reaching middle of pronotum; surface between all pronotal depressions distinctly elevated. Medioapical portion with irregular and sometimes indistinct diagonal elevations between punctures. Elytra slightly longer or about as broad as long, 1.8 times as long as pronotum, somewhat parallel-sided or distinctly broadened posteriad; lateral portions narrowly impressed, slightly explanate in middle; hind margins somewhat straight or rounded. Dorsal surface of each elytron without or with strong irregular diagonal elevations between punctures. Hind wings fully developed. Metatarsi about twice shorter than metatibia. Abdomen convex, slightly broader than elytra, with two small oval wing-folding patches in middle of abdominal tergite IV and narrow palisade fringe on apical margin of abdominal tergite VII. Male. Posterior margin of abdominal tergite VIII straight. Posterior margin of abdominal sternite VIII rounded. Aedeagus with significantly broadened and relatively short basal portion, slightly narrowed toward middle; median lobe wide and short, with widely rounded apex, with small indistinct apical excision; mediolateral portions with short sclerotized accessory plates, curved latero-apicad, each rounded apically; parameres narrow, significantly shorter than apex of median lobe, slightly curved in preapical portions, each with relatively narrowed apex with two long and two short apocal setae; internal sac wide and long, with field of large spines in apical and paired oval structures in basal portions (Fig. 4). Lateral aspect of the aedeagus as in Fig. 5; apical portion of median lobe slightly broadened, with rounded apex, slightly crenulated ventroapically. Female. Posterior margin of abdominal tergite VIII straight. Posterior margin of abdominal sternite VIII slightly rounded. Accessory sclerite short, from widest basal portion gradually narrowed toward small rounded apex (Fig. 17). Spermatheca not recognized. Comparative notes. Based on the general shape of the aedeagus, O. longicorne is related to the amplissimum group, recently erected by Shavrin (2023) for two species from the Himalayan region. Regarding the general shape of the aedeagus, with narrowed parameres and the presence of medioapical excision of the median lobe, O. longicorne is somewhat similar to the Nepalese O. bilobum Shavrin, 2023, but the median lobe of O. longicorne is slightly longer and narrower, with significantly less pronounced excision, less curved shorter parameres and with different details of the internal sac. It can be distinguished from both species by the longer body, elongate antennomeres 4 – 10, the shape of the pronotum widest in middle, shorter elytra, different morphology of the aedeagus, and the shape of the female accessory sclerite. Also see the key below.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958332BC448BE097110969FEF0.taxon	distribution	Distribution. North-eastern Mongolia, Russia (Buryatia, Amur Area) (Fig. 20).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958332BC448BE097110969FEF0.taxon	biology_ecology	Bionomics. Specimens were collected at elevations from 260 to 350 m a. s. l. A specimen from Buryatia was collected in horse dung (Voincov 2010). A specimen from Amur Area was collected by sifting mosses and litter.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958332BC448BE097110969FEF0.taxon	discussion	Remarks. Omalium longicorne was originally described from “ Nördliche Mongolei (Shangai [= Khangai Mountains]) ” without providing of the exact locality. It was recorded from southern Buryatia (Voincov 2010; Shavrin 2010). I decided to redescribe this species using additional specimens provided in the listed papers above. The habitus, the aedeagus and the female accessory sclerite are illustrated for the first time. It is here recorded from Amur Area for the first time.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958339BC448BE0958A0B2CF9CA.taxon	discussion	Remarks. Omalium caesum is widely distributed in the Palaearctic region (Schülke & Smetana 2015). It was recorded from Sverdlovsk (Belskaya & Solodovnikov 2003; Ermakov et al. 2017) and Tyumen areas (Bukhkalo et al. 2012), and Kamchatka Territory (Lobkova & Semenov 2015). Shavrin (2010) recorded it from Khanty-Mansi Autonomous Region and Krasnoyarsk Territory, but these specimens were misidentified with O. rivulare and O. strigicolle (see below). Eppelsheim (1887) recorded it from “ Amur: Askold. ”, but it seems to be a possible misidentification.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958339BC458BE097EF08A1FF64.taxon	discussion	Remarks. Records of the western Palaearctic O. excavatum from Tobolsk by J. Sahlberg (1880) and Babenko (1982) from western Siberia seem to be erroneous.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958338BC468BE090040FFFF8B4.taxon	description	(Figs 2, 6 – 7, 14, 21)	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958338BC468BE090040FFFF8B4.taxon	materials_examined	Type material examined. Holotype ♂ (Fig. 2; dissected): ‘ КемеровскаЯ обл., Заповедник | « КУЗнецкий АлатаУ », БольшаЯ | ЦерковнаЯ, 26 км ЮЮЗ | Белогорска, 1300 – 1450 м н. У. м., | над границей леса, 26.08.1993. | С. Головач и В. Грачёв [Kemerovo Area, Kuznetsk Alatau Nature Reserve, Bol`shaya Tserkovnaya, 26 km SSW Belogorsk, 1300 – 1450 m a. s. l., timberline, 26.08.1993. S. Golovatch & V. Gratchev leg.] ’ <printed>, ‘ HOLOTYPE | Omalium | golovatchi sp. n. | Shavrin A. V. des. 2025 ’ <red, printed> (ZMM). Paratypes: 3 ♂♂, 1 ♀ (dissected): same data as the holotype (2 ♂♂: cSh; 1 ♂, 1 ♀: ZMM); 2 ♂♂ (dissected), 2 ♀♀ (dissected): ‘ КемеровскаЯ обл., НовокУЗ- | нецкий р-н, Ю с. КУЗедеево, | “ Липовый Остров ”, бассейн | р. Кондома, склоны распадков | блиЗ р. Малый Тёш. Подстилка, | мхи, дернина под липой с | пихтой и береЗой, высокотра- | вьем, Злаками, осокой, | 20.07.1994. А. Б. Рывкин, № 28 [Kemerovo Area, Novokuznetskiy District, S Kuzedeevo vill., “ Lipovyi Ostrov ”, basin of Kondoma River, slopes of mountains near Malyi Tyosh River. Litter, mosses, sod under linden with fir and birch, high grasses, grains, sedges, 20.07.1994, A. B. Ryvkin leg. N 28] ’ <printed> (ZMM). All paratypes with additional red printed label: ‘ PARATYPE | Omalium | golovatchi sp. n. | Shavrin A. V. des. 2025 ’.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958338BC468BE090040FFFF8B4.taxon	description	Description. Measurements (n = 9): HW: 0.52 – 0.60; HL: 0.35 – 0.39; OL: 0.12 – 0.15; TL: 0.07 – 0.10; AL (holotype): 1.07; PL: 0.41 – 0.50; PWmax: 0.65 – 0.77; PWmin: 0.55 – 0.66; ESL: 0.62 – 0.81; EW: 0.85 – 0.97; MTbL (holotype): 0.52; MTrL (holotype): 0.21 (MTrL 1 – 4: 0.09; MTrL 5: 0.12); AW: 0.90 – 1.00; AedL: 0.52 – 0.57; BL: 2.72 – 3.45 (holotype: 3.05). Habitus as in Fig. 2. Body yellow-brown to reddish-brown, with darker head and abdomen (lateral portions of pronotum, elytra and paratergites of abdomen paler); mouthparts, antennae and legs yellowish to yellow-brown (tarsi usually slightly paler). Head with dense and moderately large punctation, sparser and finer on clypeus and larger and denser in middle; neck with dense or moderately sparse punctation about as that in middle part of head; punctation of pronotum irregular and sparse, in medioapical portion about as that in middle of head but slightly larger, coarser and deeper, mediobasal part usually with sparser and finer punctation with median elevation sometimes without punctures in middle and mediobasal third, lateral portions with sparse and large irregular punctation (one specimen with fine and sparse punctation in middle); scutellum without punctures; punctation of elytra very dense, significantly larger, deeper and coarser than that in medioapical part of pronotum, finer around scutellum and finer and sparser along suture, each elytron with distance between punctures in middle about as long as diameter of nearest puncture; abdominal tergites with dense and fine punctation, sparser and less distinct in middle of each tergite and on abdominal tergites VI – VIII. Anterior portion of clypeus with dense transverse microsculpture, laterobasal parts of clypeus with irregular, dense and diagonal microreticulation, median and infraorbital portions without visible meshes; neck without or with fine transverse sculpture; scutellum with dense and moderately coarse isodiametric sculpture; abdomen with dense isodiametric microreticulation. Apical part of head with several erect and moderately long setae; lateral margins of pronotum with several fine and short setae, visible in some specimens; abdomen with relatively dense and short setae; anterior and posterior margins of pronotum, and posterior margin of elytra with row of very short cuticular fringe. Head 1.4 – 1.5 times as broad as long, with distinctly elevated middle part and infraorbital portions, with broad clypeus and strongly distinctly explanate supra-antennal elevations; anteriomedian depressions deep, wide and elongate, each reaching level of anterior margin or anterior third of eye; posteriolateral margins of clypeus subparallel, stretching posteriad toward level of anterior third of eye. Each laterobasal portion of clypeus with irregular diagonal narrow wrinkles, infraorbital portions with irregular elevations between punctures and narrow longitudinal elevations in posterior portions, sometimes forming three to four elongate wrinkles, with significantly more elevated wrinkle on the level of lateral margin of neck; each mediodorsal margin of infraorbital portion near eye with irregular diagonal wrinkles. Anteocellar fovea sublinear, deep and elongate, each reaching level of anterior third or apical margin of eye. Temples convex, 1.5 – 1.7 times as long as longitudinal length of eye, from posterior margin of eyes gradually narrowed toward neck. Nuchal constriction moderately wide and deep. Ocelli small, indistinct in paler specimens; distance between ocelli about twice as long as distance between ocellus and posterior margin of eye. Antenna with elongate antennomeres 1 – 7, slightly elongate 8 and slightly transverse 9 – 10; antennomere 3 about as long as and distinctly narrower than 2, 4 slightly shorter than 3, 5 slightly longer than 4, 6 slightly broader than 5, 7 slightly broader than 6, 8 slightly shorter and broader than 7, 9 – 10 slightly shorter and broader than 8. Pronotum distinctly convex in middle, with significantly broadened and impressed, flattened and explanate lateral portions, 1.5 times as broad as long, from widest middle significantly more narrowed posteriad than anteriad. Apical angles broadely widened, slightly protruded anteriad. Anterior margin widely rounded, slightly shorter than rounded posterior margin. Laterobasal margins widely concave in front of subacute hind angles. Lateral portions narrowly marginated, with distinct crenulate lateral edges, each with deep and significantly broadened elongate depressions slightly behind middle. Surface of disc with two elongate and moderately deep longitudinal depressions, broadened in mediobasal portion, with additional oval fine to moderately deep medioapical depression; each lateroapical portion with indistinct or distinct curved narrow elevation, reaching about middle of pronotum; surface between all pronotal depressions strongly and narrowly elevated. Medioapical portion with irregular diagonal and longitudinal elevations between punctures in some specimens. Elytra short, 1.1 – 1.3 times as broad as long, 1.5 – 1.6 times as long as pronotum, flattened in middle, distinctly broadened posteriad; lateral portions widely impressed and strongly explanate; lateral margins with distinct irregular elevations, stronger in middle; hind margins straight of slightly rounded. Dorsal surface of each elytron with strong diagonal elevation between punctures. Hind wings fully developed, but moderately small. Metatarsi distinctly more than twice shorter than metatibia. Abdomen without wing folding patches in the middle of abdominal tergite IV and with indistinct narrow palisade fringe on apical margin of abdominal tergite VII. Male. Posterior margin of abdominal tergite VIII straight or slightly concave. Posterior margin of abdominal sternite VIII truncate or slightly concave. Aedeagus with broadened basal portion, gradually narrowed toward middle; median lobe narrow, elongate, from middle slightly narrowed apicad toward rounded apex; mediolateral portions with short sclerotized accessory plates, slightly curved lateroapicad, each rounded apically; parameres relatively wide, significantly shorter than apex of median lobe, distinctly curved in preapical portions, each with two long apical and two long preapical setae; internal sac wide and long with two oval and two narrow sclerotized structures in basal portion (Fig. 6). Lateral aspect of the aedeagus as in Fig. 7; apical portion gradually narrowed toward apex slightly curved ventroapicad. Female. Posterior margin of abdominal tergite VIII straight. Posterior margin of abdominal sternite VIII rounded. Accessory sclerite with wide basal portion strongly narrowed toward narrow elongate apical part with small rounded apex (Fig. 14). Spermatheca not recognized. Comparative notes. Based on the presence of linear anteocellar foveae and the general shape of the aedeagus, O. golovatchi sp. nov. belongs to the Caesum group (Zanetti 1987). Based on the general shape of the median lobe in parameral and lateral view, it somewhat similar to the Palaearctic O. littorale Kraatz, 1857, known from the western Palaearctic region, including Central Asia (Shavrin 2023), but differs from it by the narrower shape of the forebody. It can be easily distinguished from all species of this group by the shape of the forebody, with significantly broadened and explanate lateral portions of the pronotum and the elytra, large, dense and coarse punctation on the significantly shortened elytra, with strong elevations between punctures, the lack of the wing folding patches in the middle of abdominal tergite IV, the morphology of the aedeagus and the shape of the female accessory sclerite.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958338BC468BE090040FFFF8B4.taxon	distribution	Distribution. Omalium golovatchi sp. nov. is known only from two localities in the southern part of Kemerovo Area, Russia (Fig. 21).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958338BC468BE090040FFFF8B4.taxon	etymology	Etymology. Patronymic; the species is named to honour Sergei I. Golovatch (Moscow), one of the collectors of the type material.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958338BC468BE090040FFFF8B4.taxon	biology_ecology	Bionomics. Specimens were collected from 340 to 1450 m a. s. l. by sifting litter and mosses in mixed forests.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795833ABC478BE095B30969F939.taxon	description	(Fig. 3)	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795833ABC478BE095B30969F939.taxon	materials_examined	Material examined. RUSSIA: AMUR AREA: 1 ♀: Selemdzhinskiy District, Norskiy Reserve, Nora River, Maltsevskiy cordon, near hut. 10.06.2005. E. M. Veselova & A. B. Ryvkin leg. (cSh).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795833ABC478BE095B30969F939.taxon	discussion	Remarks. The Holarctic Omalium oxyacanthae (Fig. 3) was recorded from Irkutsk (Shavrin et al. 1999), Chita (Shavrin 2010) and Magadan (Ryabukhin 1999, 2002) areas, and Kamchatka Territory (Ryabukhin 1999, 2010, 2020, 2024). Eppelsheim (1893) recorded it from Irkut valley, but all studied specimens from NMW identified as “ oxyacanthae ” refers to O. subsolanum (see below). It is here recorded from Amur Area for the first time.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795833ABC418BE097F8083CF99C.taxon	description	(Fig. 22)	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795833ABC418BE097F8083CF99C.taxon	materials_examined	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 58 º 20 ’’, ‘ septentrionis Thoms. ’, ‘ 2686 ’, ‘ 7202 E 91 + ’ (SMNH); 1 ♂: ‘ Vorogovo 61 º’, ‘ Sibir Jeniseie’, ‘ 2599 ’, ‘ 7203 E 91 + ’ (SMNH); 1 ♀: ‘ Worog Selo’, ‘ Sibir Jeniseie’, ‘ Ndsk & Stbg’, ‘ languidum Mäklin’, ‘ 7204 E 91 + ’ (SMNH); 1 ♀: ‘ Worog Selo’, ‘ Sibir Jeniseie’, ‘ Ndsk & Stbg’, ‘ languidum var.? ♀ ’, ‘ (H. binotatum) + ’, ‘ 72051 E 91 + ’, ‘ 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 1 st 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).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795833ABC418BE097F8083CF99C.taxon	discussion	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.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795833CBC428BE097940803FF48.taxon	discussion	Remarks. Omalium allardi is a widespread species in the western Palaearctic region (Schülke & Smetana 2015), introduced in New Zealand (Klimaszewski et al. 1996). The record from Siberia (Schülke & Smetana 2015) is erroneous. It was possibly based on misidentifications provided by Shavrin (2001, 2010). Specimens from Shelekhov (Shavrin 2001) were misidentified and belong to O. septentrionis (see above), and specimens from Olkhon Island to O. curtipenne (see below), respectively.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795833FBC5E8BE090680F07FB54.taxon	description	(Figs 10 – 11, 23, 25 – 28, 31)	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795833FBC5E8BE090680F07FB54.taxon	materials_examined	Type material examined. Holotype of Homalium curtipenne Mäklin, 1878 ♂: ‘ Dudino’ <printed>, ‘ Sibir’ <printed>, ‘ Jeniseie’ <printed>, ‘ curtipenne | Mäklin’ <handwritten in black>, ‘ 7164 E 91 + ’ <blue, printed>, ‘ probably type [handwritten] M. K. Thayer 2010 ’ <printed> (SMNH). Lectotype (here designated) of Omalium lacki Bernhauer, 1940 ♂ (dissected): ‘ Bear Island: Fugleodden. | 13. vii. [handwritten in black] 1932. ’ <printed>, ‘ D. Lack. | B. M. 1932 - 378. ’ <printed>, ‘ Arct. Ocean | Bären Insel | Brit. Museum’ <handwritten in black>, ‘ lacki Brh | Type. ’ <handwritten in black>, ‘ Lacki Brnh | Type | Omalium’ <red, handwritten in black>, ‘ Chicago NHMus | M. Bernhauer | Collection’ <printed>, ‘ Syntype | lacki Bernh. | det. M. K. Thayer 19 [printed] 90 ’ <handwritten in black>, ‘ SYNTYPE | teste D. J. Clarke 2014 | GDI Imaging Project’ <violet, printed>, ‘ PHOTOGRAPHED | Kelsey Keaton 2014 | Emu Catalog’ <blue, printed>, ‘ FMNHINS | 2819646 | FIELD MUSEUM’ <printed, with barcode on left side of the label>, ‘ LECTOTYPE | Omalium | lacki Bernhauer, 1940 | Shavrin A. V. des. 2025 ’ <red, printed>, ‘ Omalium | curtipenne Mäklin, 1878 | Shavrin A. V. det. 2025 ’ <printed> (FMNH). Paralectotypes: 1 ♀: ‘ Bear Island: Fugleodden. | 5. viii. [handwritten in black] 1932. ’ <printed>, ‘ D. Lack. | B. M. 1932 - 378. ’ <printed>, ‘ BRIT. MUS. | DON. ARROW’ <printed>, ‘ Lacki Brnh | Type | Omalium’ <red, handwritten in black>, ‘ Chicago NHMus | M. Bernhauer | Collection’ <printed>, ‘ Syntype | lacki Bernh. | det. M. K. Thayer 19 [printed] 90 ’ <handwritten in black>, ‘ SYNTYPE | teste D. J. Clarke 2014 | GDI Imaging Project’ <violet, printed> (FMNH); 1 ♂: ‘ Bear Island: | Fagleodden. | 5. VIII. [handwritten] 1932. ’ <printed>, ‘ D. Lack. | B. M. 1932 - 378. ’ <printed>, ‘ W. Steel coll. | B. M. 1969 - 552. ’ <printed> (BMNH); 1 ♀ (right antenna missing): ‘ Bear Island: | Fugleodden. | 8. VII. [handwritten] 1932. | D. Lack. | B. M. 1932 - 378. ’ <printed> (BMNH). All paralectotypes with additional labels: ‘ Paralectotype’ <red, printed>, ‘ Omalium | curtipenne Mäklin, 1878 | Shavrin A. V. det. 2025 ’ <printed>. The photographs of the habitus and type labels are also available in Arthropod Collections Database of FMNH (last access: 24.04.2025). Material examined. TYUMEN AREA: 1 ♀: Uvatskiy District, 10 km S Gornoslinkino, near Tobolsk Field Research Station of Severtsov Institute, near mouth of Varpak River. Clay bank of river: near water and among sedges. 12.09.2003. A. B. Ryvkin leg. (cSh); KRASNOYARSK TERRITORY: 1 ♂: Turukhanskiy District, Central Siberian State Reserve, middle reaches of Bol`shaya Raskosaya River. Pleurozium schreberi, Hylocomium splendens etc. in forest with Picea obovata, Betula sp., Pinus sibirica, Abies sibirica, Juniperus sp., Larix sibirica, Vaccinium vitis-idaea and V. myrtillus. 24.05.1992. V. B. Semenov leg. (ZMM); 1 ♂: same data, Bolshaya Varlamovka River, middle reaches of Bol`shaya Raskosaya River. 23.05.1992. (cSh); 1 ♂: same Reserve, Stolbovaya River basin: lower reaches of Birapchana River near Kruten`kiy stream. 110 m a. s. l., drift in willow bushes at rill bank. 26.06.1993. V. B. Semenov leg. (cSh); 2 ♀♀: same data, Stolbovaya River basin near mouth of Kruten`kiy stream. 110 m a. s. l., loamy river bank with Salix sp., dead Poaceae gen. spp. etc., in drift 23.06.1993 (ZMM); 1 ♀: Turukhanskiy District, Nizhnyaya Sarchikha River near Kamenka River mouth. 150 m a. s. l., under mosses near bank of the river. 06 – 07.07.1992. V. B. Semenov leg. (cSh); 1 ♀: same District, Mirnoye. Soil traps. 05 – 15.08.1989. L. B. Rybalov leg. (ZMM); 8 ♂♂, 9 ♀♀: same data. 06 – 20.07.1990. (cSh, ZMM); 1 ♀: ‘ Nikandrovski insula 70 º 40 ’’, ‘ 2190 ’, ‘ 7165 E 91 + ’, ‘ curtipenne Mäkl. ’ (SMNH); EVENKIA: 3 ♂♂, 2 ♀♀: Baykitskiy District, Bol`shoy Baykitik River, 1 – 3 km up-stream Baykit. 150 m a. s. l., mosses at bank of the river. 21.09.1993. A. B. Ryvkin leg. (cSh, ZMM); 2 ♂♂: same District, basin of left tributary of Bol`shoy Baykitik River near Baykit. 180 m a. s. l., mosses and litter at bank of stream under Picea obovata, Larix? czekanowskii, Betula sp., Salix sp., Alnus sp., with Sphagnum spp., Plagiomnium spp., Pleurozium schreberi, Hylocomium splendens, grasses, Linnaea borealis, Vaccinium vitis-idaea, Rosa sp., Ledum sp., Chamaedaphne calyculata etc. 02.10.1993. A. B. Ryvkin leg. (cR); 1 ♂: same data. 150 m a. s. l., mosses and litter at bank of stream with sparse Betula sp., Salix sp., Alnus sp., young Picea obovata, grasses etc. 30.09.1993. (cSh); 1 ♀: same District, 3 km up-stream of Baykit. 160 – 170 m a. s. l., river bank with hummocks: mosses, litter and drift among Salix spp., Alnus sp., Betula? fruticosa with Calamagrostis sp., Carex spp., Filipendula ulmaria, Equisetum sp. etc. at bottom of stony slope. 26.09.1993. A. B. Ryvkin leg. (cR); 1 ♂: same District, Podkamennaya Tunguska River, environs of Kuz’movka village, Kuz’movskiy Rill. 60 m a. s. l., moss and litter on slope near the rill: Picea obovata, Abies sibirica, Larix sibirica, Salix sp., Alnus sp., Lonicera altaica, Ribes sp., Equisetum sp., Vaccinium vitis-idaea, V. myrtillus, sparse Betula, Hylocomium splendens, Pleurozium schreberi etc. 12.08.1989. A. B. Ryvkin leg. (cSh); TUVA: 1 ♀: Todzhenskiy District, Toora-Khem village. 900 m a. s. l. Evening flying in the yard and in the garden. 04.06.1992. A. B. Ryvkin leg. (cR); 2 ♂♂, 1 ♀: Mongun-Tayginskiy District, Khindig-Khol` Lake. 2600 m a. s. l., half-ruined rocky outliers, in nests of Alticola strelzowi. 02.09.1984. (ZMM); IRKUTSK AREA: 4 ♂♂: Bodaibinskiy District, Vitimskiy Nature Reserve, Oron Lake, upper flow of right tributary of Pravaya Polovinka (left bank), 57 ° 07.446 ’ N 116 ° 37.131 ’ E. Valley of river with Picea and Betula. 07.06.2015. I. V. Enushchenko leg. (cSh); 2 ♂♂, 1 ♀: same data, right bank of Pravaya Polovinka River, 57 ° 07.360 ’ N 116 ° 36.692 ’ E, ~ 500 m downstream of second rigth tributary. 08.06.2015. I. V. Enushchenko leg. (cSh); 1 ♀: same data, Oron Lake, cordon, 57 ° 11 ’ 29.2 ’’ N 116 ° 26 ’ 19.6 ’’ E. 67 m a. s. l., swampy bed of stream flowing to the lake. 18.07.2016. I. V. Enushchenko leg. (cSh); CHITA AREA: 1 ♀: Kalarskiy District, Udokan Mts., right side of Sredniy Sakukan River, mouth of Medvezhiy Stream. 22.07.2014. I. V. Enushchenko leg. (cSh); YAKUTIA: 1 ♂, 1 ♀: Suntar-Khalta Mts., valley of Tyry River, Nezhdanskoye, Kidyrki River near Khalya River. 800 – 950 m a. s. l. 11 – 18.08.1991. S. K. Alekseev leg. (cSh); MAGADAN AREA: 1 ♂: Magadan. Alnus forest. 19.08 – 18.09.1980. S. P. Bukhkalo leg. (cSh); 1 ♂: Ten`kinskiy District, basin of Detrin River, Vakkhanka Rill (near ford). Soil traps. 28.06 – 06.07.1983. S. P. Bukhkalo leg. (cSh); 1 ♂: Khasynskiy District, right bank of Dukcha River, 59 ° 37 ’ 52.0 ’’ N 150 ° 56 ’ 04.3 ’’. 104 m a. s. l. 04.06.2016. I. V. Enushchenko leg. (cSh); CHUKOT AUTONOMOUS REGION: 1 ♀: Wrangel Island, Nalednoye Swamp. Soil traps. 02 – 13.06.1983. S. P. Bukhkalo leg. (ZMM); AMUR AREA: 1 ♀: Zeyskiy District, Zeyskiy Nature Reserve, left side of Bol’shaya Erakingra River NE of 52 nd km cordon, N 54.09080 ° E 126.87963 °. 623 m a. s. l., mosses and litter on / among stones in dry channel. 21.08.2016. A. B. Ryvkin leg. (cSh).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795833FBC5E8BE090680F07FB54.taxon	description	Redescription. Measurements (n = 50): HW: 0.47 – 0.64; HL: 0.35 – 0.43; OL: 0.12 – 0.19; TL: 0.06 – 0.10; AL (averaged): 1.17; PL: 0.43 – 0.52; PWmax: 0.70 – 0.79; PWmin: 0.65 – 0.74; ESL: 0.70 – 1.02; EW: 0.92 – 1.01; MTbL (averaged): 0.55; MTrL (averaged): 0.26 (MTrL 1 – 4: 0.10; MTrL 5: 0.15); AW: 0.93 – 1.13; AedL: 0.62 – 0.72; BL: 2.25 – 3.70 (lectotype of O. lacki: 3.15). Habitus as in Fig. 23. Body yellowish-brown to reddish-brown, with paler elytra (some specimens with markedly paler lateral and basal margins of pronotum); antennomeres 5 – 11 or 6 – 11 brown; mouthparts, antennomeres 1 – 4 or 1 – 5 and legs yellow to yellow-brown (tarsi usually paler). Punctation of head irregular, moderately fine, denser in middle, clypeus without or with fine and sparse punctation; neck with fine and sparse punctation; pronotum with moderately dense punctation, about as that in middle part of head or slightly larger and deeper, sometimes finer and sparser in medioapical and sparser in mediobasal and lateral portions; punctation of elytra denser, larger and deeper than that on pronotum, denser around scutellum, finer and sparser along suture; abdominal tergites with indistinct and fine punctation, sometimes invisible in some specimens. Head with dense and coarse microsculpture: transverse on clypeus, diagonal on laterobasal parts of clypeus and infraorbital portions, sometimes isodiametric between lateral parts of clypeus and eye, and longitudinal and subdiagonal in middle portion; neck with transverse microsculpture, sometimes invisible in middle; pronotum without or with fine isodiametric or longitudinal microreticulation of traces of it in middle portion (some specimens with isodiametric or longitudinal microsculpture in latero-basal portions); scutellum with dense isodiametric meshes; elytra without microreticulation; abdomen with dense isodiametric microsculpture. Anterior part of clypeus with several erect moderately long setae; abdominal tergites with fine and relatively dense setation; posterior margin of pronotum with row of short cuticular fringe, invisible in some specimens. Head 1.3 – 1.4 times as broad as long, flattened or slightly elevate in middle, with wide clypeus and slightly explanate supra-antennal elevations; anteriomedian depressions wide, shallow or moderately deep, reaching level of anterior third or middle of eyes; each posteriolateral margin of clypeus diagonally stretching posteriad toward level of anterior third or middle of eye. Mediodorsal surface without or with distinct diagonal or longitudinal elevations between punctures, each infraorbital portion near eye and its posterior part with three to five longitudinal irregular wrinkles, indistinct in some specimens. Anteocellar fovae oval, deep and relatively short, but sometimes elongate and slightly convergent latero-apicad toward level of posterior third or middle of eyes. Temples twice as long as longitudinal length of eye. Nuchal constriction wide and deep. Distance between ocelli 1.7 times to slightly more than twice as long as distance between ocellus and posterior margin of eye. Antennomeres 7 – 10 slightly transverse; basal antennomere about two and a half to three times as long as broad, antennomere 2 distinctly narrower and shorter than basal antennomere, 3 slightly longer and narrower than 2, 4 small, about twice shorter than 3, 5 slightly loger and broader than 4, 6 – 7 slightly broader than 5, 8 distinctly broader than 7, 9 – 10 slightly longer and broader than 8, apical antennomere 1.3 – 1.5 times as long as preceding segment. Pronotum distinctly convex, 1.5 – 1.6 times as broad as long, 1.2 – 1.4 times as broad as head, widest in or slightly above middle, more narrowed posteriad (gradually or strongly) than anteriad toward obtuse or subacute hind angles. Lateral portions widely impressed, slightly or distinctly explanate, especially in middle and lateral portions in some specimens, each with deep and elongate depressions behind middle. Surface of disc with two shallow or moderately deep elongate longitudinal depressions, without or with indistinct oval medioapical depression; each lateroapical portion with curved narrow elevation, reaching middle of pronotum; surface between all pronotal depressions not or slightly elevated. Middle portion without or with irregular and indistinct diagonal elevations between punctures. Elytra slightly or disitnctly broader than long, 1.6 – 1.9 times as long as pronotum, slightly or strongly broadened posteriad. Dorsal surface of each elytron with strong irregular transverse and diagonal elevations between punctures. Male. Posterior margin of abdominal tergite VIII truncate or indistinctly concave. Posterior margin of abdominal sternite VIII truncate or somewhat rounded. Aedeagus with broadened basal portion, gradually narrowed toward middle; median lobe narrow, elongate, with small rounded apex, from about middle with narrow rounded lateral projections; mediolateral portions with relatively long and narrow sclerotized accessory plates, slightly curved latero-apicad, each rounded apically; parameres wide, significantly shorter than apex of median lobe, each narrowed and curved in preapical portion, with four moderately long apical setae; internal sac relatively narrow, long, with two elongate sclerotized structures in basal portion (invisible in some specimens) (Figs 25, 27). Lateral aspect of the aedeagus as in Fig. 26; apical portion of median lobe relatively narrow, with rounded apex, distinctly crenulate ventrodorsally (Figs 26, 28). Female. Posterior margin of abdominal tergite VIII straight. Posterior margin of abdominal sternite VIII straight or slightly rounded. Accessory sclerite moderately long and wide, from widest basal portion gradually narrowed toward apex (Fig. 10). Spermatheca as in Fig. 11. Comparative notes. Based on the general shape of the habitus and the aedeagus, O. curtipenne is somewhat similar to the Holarctic O. strigicolle, from which it can be distinguished by the finer punctation of the head and the pronotum, slightly more transverse pronotum, which is stronger narrowed posteriad from the middle, the shorter elytra, narrower median lobe with presence of narrow lateral projections in about middle and distinctly more narrowed apex, the lack of the lateroapical hook in apical portion of the medion lobe (if viewed laterally), the shape of the female accessory sclerite and other details of the morphology of the aedeagus.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795833FBC5E8BE090680F07FB54.taxon	distribution	Distribution. Omalium curtipenne is widely distributed in the Palaearctic region from Norway to Far Eastern Russia; faunistic records between Scandinavia and western Siberia are unknown (Fig. 31).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795833FBC5E8BE090680F07FB54.taxon	biology_ecology	Bionomics. Omalium curtipenne inhabits mixed coniferous-deciduous forests with Picea, Pinus, Abies, Larix, Betula, etc. It most often is found in wet habitats near streams and rivers and can be sifted from mosses, litter and drift. Some specimens were collected in swampy habitats; occasionally it inhabits nests of rabbits and can be collected flying in the evening. The species is recorded from elevations between 60 m a. s. l. to 2600 m a. s. l. The beetles were collected from May to November.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795833FBC5E8BE090680F07FB54.taxon	discussion	Remarks. Homalium curtipenne was described based on the holotype from “ Dudino (lat. bor. 69 ° 15´) … ”. This specimen was found in the collection of SMNH (see above). Omalium lacki was originally described from “ … Bären-Insel im nördlichen Eismeer (Fugleodden) [the southernmost island of the Norwegian Svalbard archipelago, Norway] ” based on an unspecified number of syntypes. These specimens were collected by “ … D. Lack in der Zeit vom 13. Juli 1932 bis 5. August 1932 … ” (Bernhauer 1940). I have studied four syntypes from FMNH and BMNH, and one male from FMNH was designated as the lectotype in order to fix the identity of the species. Based on the general shape of the body and morphology of the aedeagus (Figs 27 – 28), it is conspecific with specimens of O. curtipenne from Siberia and Far Eastern Russia. Thus, I synonymized O. lacki with it. Omalium curtipenne was recorded from Krasnoyarsk Territory (J. Sahlberg 1880), Irkutsk Area (Shavrin 2007), Buryatia (Eppelsheim 1893, Shavrin 2010) and Chukot Autonomous Region (Ryabukhin 1999). It was recorded by Shavrin (2010) as O. caesum from Kamennyi Dubches (Krasnoyarsk Territory). Additional material both for O. curtipenne and O. lacki from Scandinavia and northern European regions of Russia is unknown. It is likely that some published records of O. strigicolle or related species from these regions should be re-studied, especially for the aedeagi in lateral position. The apical portion of the aedeagus of O. curtipenne in lateral position is not forming a hook and is slightly crenulate ventrodorsally (compare Figs 26, 28, Fig. 53 i in Zanetti (2011), and Fig. 49). It should also be taken into account that O. curtipenne is variable in some details and proportions of the forebody: somewhat different shape of the anteocellar foveae, the shape of the pronotum can be slightly or more narrowed posteriad, with less or more flattened and explanate lateral portions, elytra can be somewhat shortened or elongate, etc. Despite this, the shape of the aedeagus is not so variable and can be confidently used for species identification. Also see the key below. It is here recorded from Tyumen Area, Evenkia, Yakutia, Amur, Chita and Magadan areas for the first time.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958323BC588BE094150AABFE60.taxon	description	(Figs 8 – 9, 12 – 13, 24, 32)	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958323BC588BE094150AABFE60.taxon	materials_examined	Type material examined. Holotype of Omalium diffine Sharp, 1889 ♀ (Fig. 24; dissected; underside of the card with handwritten numbers: ‘ 8.5.81 ’): ‘ Type’ <round label with red margin>, ‘ Japan [underlined by yellow] | G. Lewis. | 1910 - 320. ’ <printed>, ‘ Hitoyoshi. | 3. V. – 8. V. 81. ’ <printed>, ‘ Omalium | diffine. | Type | D. S. ’ <handwritten in black>, ‘ NHMUK 015009857 ’ <printed, with barcode on the left side of the label>, ‘ Omalium | japonicum Sharp, 1874 | Shavrin A. V. det. 2025 ’ (BMNH). Material examineD. JAPAN: 1 ♂: ‘ Japan Tokyo Tachikawa 6. V. 39 Y. Yano’, ‘ M. Cameron. Bequest. B. M. 1955 - 147. ’, ‘ Omalium japonicum Shp. ’, ‘ Omalium diffine Sharp P. M. Hammond det. 1989 ’ (BMNH).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958323BC588BE094150AABFE60.taxon	description	Redescription. Measurements (n = 2): HW: 0.42 – 0.45; HL: 0.25 – 0.26; OL: 0.13 – 0.15; TL: 0.04 – 0.05; AL (holotype): 0.67; PL: 0.33 – 0.35; PWmax: 0.52 – 0.56; PWmin: 0.47 – 0.50; ESL: 0.65 – 0.72; EW: 0.67 – 0.75; MTbL (holotype): 0.32; MTrL (holotype): 0.22 (MTrL 1 – 4: 0.07; MTrL 5: 0.15); AW: 0.67; AedL: 0.47; BL: 2.20 (holotype) – 2.38. Habitus as in Fig. 24. Body and antennomeres 6 – 11 brownish, with distinctly paler elytra; mouthparts, antennomeres 1 – 5 and legs yellow. Head with sparse and fine punctation, denser in middle (holotype without distinct punctures on infraorbital portions); neck with very sparse and fine punctation; punctation of pronotum denser, larger and deeper than that in middle part of head, sparser in middle and mediobasal portions and finer in basal area; punctation of elytra about as that on pronotum, but slightly larger and deeper, finer and sparser in middle parts of each elytron; abdominal tergites without visible punctation. Head with dense irregular microsculpture: transverse in middle of clypeus and dense and diagonal in each laterobasal parts of it, middle portion with diagonal and isodiametric meshes and infraorbital portions with diagonal and longitudinal microreticulation; neck with fine indistinct longitudinal microsculpture; pronotum, elytra and scutellum without sculpture; abdominal tergites with dense isodiametric microreticulation. Head with several erect and long setae on anterior part of clypeus and with additional separate long erect setae on each laterobasal part of clypeus and posteriolateral parts of infraorbital portions; lateral portions of pronotum with indistinct sparse and short setation; abdominal tergites with fine and relatively dense setation. Head transverse, 1.6 – 1.7 times as broad as long, indistinctly elevated in middle, with broad slightly elongate clypeus and distinctly explanated and convex supra-antennal elevations; anteriomedian depressions moderately deep and wide; each posteriolateral margins of clypeus slightly narrowed basad and reaching level of anterior third of eye. Median surface with fine diagonal elevations between punctures, with indistinct narrow elevations along posterior margins of each eye. Anteocellar foveae suboval and moderately deep, reaching level of posterior third of eyes. Temples short, about three times shorter than longitudinal length of eye, relatively strongly narrowed posteriad. Nuchal constriction moderately wide and deep. Ocelli located slightly below level of posterior margins of eyes; distance between ocelli slightly less than distance between ocellus and posterior margin of eye. Antennomeres with slightly transverse antennomeres 6 – 7 and distinctly transverse 8 – 10; antennomere 4 about as long as broad, more than twice shorter than 3, 5 slightly broader than 4, 6 – 7 slightly longer and distinctly broader than 5, 8 broader than 7, 9 – 10 slightly longer and distinctly broader than 8, apical antennomere 1.4 times as long as preceding segment, from middle gradually narrowed toward rounded apex. Pronotum 1.5 – 1.6 times as broad as long, from widest middle slightly more narrowed posteriad than anteriad toward obtuse hind angles. Apical angles not protruded anteriad. Anterior margin slightly concave in middle. Lateral portions narrow, not explanate, with moderately wide and deep elongate impressions behind middle. Surface of disc with two shallow longitudinal depressions; each lateroapical portion with indistinct and short elevation, reaching about middle of pronotum; surface between longitudinal depressions slightly elevated. Middle portion with irregular and fine, transverse elevations between punctures. Elytra slightly broader than long, twice as long as pronotum, indistinctly broadened posteriad; lateral portions marginate, but not explanate; hind margins slightly rounded. Dorsal surface of each elytron with strong diagonal elevations between punctures. Metatarsi 1.4 times as long as metatibia. Abdomen about as broad as or slightly narrower than elytra. Male. Posterior margin of abdominal tergite VIII straight. Posterior margin of abdominal sternite VIII rounded. Aedeagus with wide basal portion, gradually narrowed toward middle; median lobe narrow and long, from widest middle portion strongly narrowed toward elongate preapical part with subacute apex, from about middle with narrow rounded lateral projections; mediolateral portions with narrow elongate accessory plates, each rounded apically; parameres wide, significantly shorter than median lobe, distinctly narrowed and curved laterad in preapical portions, each with two long apical and two short preapical setae; internal sac wide and long, with two oval and two narrow sclerotized structures in basal portion (Fig. 8). Lateral aspect of the aedeagus as in Fig. 9; apical portion of median lobe (lateral view) hook-shaped, with slightly ventrodorsad curved, subacute hind angle and rounded apex. Female. Posterior margins of abdominal tergite VIII and sternite VIII trunctate. Female accessory sclerite elongate, from widest basal portion gradually narrowed toward small rounded apex (Fig. 12). Spermatheca as in Fig. 13. Comparative notes. Based on the general shape and the coloration of the body, proportions of the antennomeres, and general shape of aedeagus and female accessory sclerite, O. diffine is similar to O. subsolanum (see below), from which it can be distinguished by the slightly narrower pronotum, longer median lobe with the presence of rounded lateral projections in about the middle, the hook-shaped apical part of the median lobe (lateral view), and other details of external and internal morphology of the aedeagus. Besides that, based on the general shape of the aedeagus and the presence of the hook in the apical part of the median lobe (if viewed laterally), O. diffine is somewhat similar to O. bambusaphilum Shavrin, 2025, recently described from Jiangxi, China (Shavrin 2025). Omalium diffine can be distinguished from the latter species by the smaller body, slightly paler coloration, sparser punctation of the head and the pronotum, longer and narrower median lobe with the presence of rounded lateral projections in about middle, narrower apical portions of the parameres and other details of the morphology of the aedeagus.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958323BC588BE094150AABFE60.taxon	distribution	Distribution. Omalium diffine is known from two localities in Honshu, Japan (Fig. 32).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958323BC588BE094150AABFE60.taxon	biology_ecology	Bionomics. Detailed bionomical data are unknown.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958323BC588BE094150AABFE60.taxon	discussion	Remarks. Omalium diffine was originally described based on the holotype from “ Hitoyoshi ”. Watanabe (1990) neither re-studied the type specimen and nor redescribed this species, but included it in a key of Omalium of Japan. Thus, based on the study of the holotype and an additional specimen, I decided to redescribe it in the present study.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958325BC5A8BE097870BAEFEAC.taxon	description	(Figs 15, 33, 36 – 37)	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958325BC5A8BE097870BAEFEAC.taxon	materials_examined	Type material examined. Lectotype (here designated) ♂ (Fig. 33): ‘ Japan. [underlined by yellow] | G. Lewis | 1910 - 320. ’ <printed>, ‘ Nagasaki. | 13.11. – 21. IV. [18] 81. ’ <printed>, ‘ Omalium | japonicum Sharp, 1874 | Shavrin A. V. 2025 ’ <printed>, ‘ LECTOTYPE | Omalium | japonicum Sharp, 1874 | Shavrin A. V. des. 2025 ’ <red, printed> (BMNH). Paralectotypes: 3 ♂♂, 3 ♀♀ (one specimen dissected; one specimen with handwritten numbers on the same plate below the specimen: ‘ 4.81 <in black> | 9.4. [18] 81 <in red> ’; one specimen with additinal handwritten label: ‘ Omalium japonicum’): first two labels same as in lectotype, with additional printed label: ‘ Omalium | japonicum Sharp, 1874 | Shavrin A. V. 2025 ’ (BMNH). Material examineD. JAPAN: 2 ♀♀: ‘ Type’, ‘ Japan. G. Lewis 1910 - 320. ’, ‘ Sharp Coll. 1905 - 313. ’, ‘ Omalium japonicum Type D. S. ’, ‘ NHMUK 015009856 ’ (BMNH); 2 ♀♀, 1 unsexed specimen (without abdomen): ‘ Japan. G. Lewis 1910 - 320. ’ (BMNH); 1 ♀: ‘ 227 ’, ‘ Japan. G. Lewis 1910 - 320. ’ (BMNH); 6 ♂♂, 5 ♀♀: ‘ Japan. G. Lewis’, ‘ Sharp Coll. 1905 - 313. ’ (BMNH); 1 ♂, 1 ♀: same the first two labels as the previous, with additional label: ‘ W. Steel coll B. M. 1969 - 552. ’ (BMNH); 1 ♀: same first two labels as the previous, with additional label: ‘ Omalium japonicum’ (BMNH); 1 ♀: ‘ 227 ’, ‘ Japan. G. Lewis 1910 - 320. ’, ‘ Omalium japonicum mihi D. S. ’ (BMNH); 1 ♂: ‘ Kanagawa Japan. Sauter’, ‘ japonicum Shp’, ‘ M. Cameron. Bequest. B. M. 1955 - 147. ’ (BMNH); 1 ♀: ‘ Japan. G. Lewis 1910 - 320. ’, ‘ Yokohama. ’ (BMNH); 1 ♂, 1 ♀: the first label as the previous, with additional label: ‘ Miyanoshita. 24. IV. – 3. V. 80. ’ (BMNH); 1 ♀: ‘ JAPAN Kobe Mayasan 15. X. 28 JEA Lewis’, ‘ M. Cameron Bequest. B. M. 1955 - 147. ’ (BMNH); 2 ♀♀: ‘ JAPAN Kobe Shinohara 8. XI. 27 JEA Lewis’ (BMNH); 2 ♂♂: ‘ JAPAN Satsuma Sakurajima. 10. III. 12. JEA Lewis’, ‘ Omalium japonicum’, ‘ M. Cameron Bequest. B. M. 1955 - 147. ’ (BMNH); 1 ♀: ‘ Daibosatsu Pass Yamanashi-pref. May- 20 th 1961 Coll. K. Mizusawa’ (BMNH); 1 ♂: Ibaraki Prefecture, Mt. Tsukuba vic. 11.11.2001. P. Jałoszýnski leg. (cSh).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958325BC5A8BE097870BAEFEAC.taxon	discussion	Remarks. Omalium japonicum was originally described from Nagasaki based on an unspecified number of syntypes. I designate the male from BMNH as the lectotype in order to fix the identity of the species. It was redescribed by Watanabe (1990) and Kim & Ahn (2014). Habitus as in Fig. 33. Measurements of the studied specimens: HW: 0.44 – 0.52; HL: 0.30 – 0.37; OL: 0.15 – 0.17; TL: 0.04 – 0.06; AL (lectotype): 0.80; PL: 0.43 – 0.45; PWmax: 0.57 – 0.62; PWmin: 0.51 – 0.56; ESL: 0.74 – 0.78; EW: 0.81 – 0.67; MTbL (lectotype): 0.45; MTrL (lectotype): 0.22 (MTrL 1 – 4: 0.09; MTrL 5: 0.13); AW: 0.79 – 0.85; AedL: 0.49 – 0.52; BL: 2.15 – 2.90 (lectotype: 2.65). Aedeagus as in Figs. 36 – 37. Female accessory sclerite as in Fig. 15. It was recorded from Honshu several times (see checklist above). To the present date, O. japonicum is known from several localities in Honshu, Japan (e. g. Watanabe 1990) and South Korea (Kim & Ahn 2014). Schülke & Smetana (2015) recorded it from Jiangsu and Shanghai (China) without providing the exact localities, so these records require confirmation.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958327BC5B8BE0904C0FE2FABC.taxon	description	(Figs 16, 29 – 30, 32, 34)	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958327BC5B8BE0904C0FE2FABC.taxon	materials_examined	Type material examined. Holotype ♂ (Fig. 34; dissected): ‘ RUSSIA: Kuril islands, | Iturup, nr. vulcan | Atsonopuri, Dobroye | Nachalo Bay, 17. VI. – 30. | VII. 2004, Plutenko’ <printed>, ‘ Museum für Naturkunde | Berlin | Sammlung M. Schülke’ <printed>, ‘ HOLOTYPE | Omalium | kurilicum sp. n. | Shavrin A. V. des. 2025 ’ (cSch). Paratypes: 2 ♀♀ (one specimen dissected; one specimen with additional printed label: ‘ Omalium [handwritten] | cf. rivulare Payk. [handwritten] | det. M. Schülke 2004 ’): same data as the holotype (cSch, cSh); 1 ♂ (dissected): ‘ КУнашир, | междУречье рек | СаратовскаЯ и ТЯтина | 44 ° 16 ’ 28 ’’ N 146 ° 07 ’ 09 ’’ | 5 – 8. VII. 2014 | leg. Ю. и Л. СУндУковы [Kunashir, interfluve of Saratovskaya and Tyatina rivers […] leg. Yu. Sundukov & L. Sundukova] ’ <printed> (cSh). All paratypes with additional red printed label: ‘ PARATYPE | Omalium | kurilicum sp. n. | Shavrin A. V. des. 2025 ’.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958327BC5B8BE0904C0FE2FABC.taxon	description	Description. Measurements (n = 4): HW: 0.65 – 0.70; HL: 0.45 – 0.47; OL: 0.20 – 0.24; TL: 0.04 – 0.05; AL (holotype): 0.97; PL: 0.50 – 0.55; PWmax: 0.82 – 0.85; PWmin: 0.77 – 0.78; ESL: 0.96 – 1.07; EW: 1.15 – 1.27; MTbL (holotype): 0.55; MTrL (holotype): 0.28 (MTrL 1 – 4: 0.12; MTrL 5: 0.16); AW: 0.87 – 1.25; AedL: 0.63 – 0.90; BL: 3.25 – 4.00 (holotype: 3.45). Habitus as in Fig. 34. Head, pronotum and abdomen reddish-brown (lateral and basal portions of pronotum, paratergites and apical tergites of abdomen distinctly paler); elytra yellow-brown, with slightly darkened mediobasal portion; antennomeres 6 – 11 brown; mouthparts, antennomeres 1 – 5 and legs yellow. Head with irregular moderately dense punctation, finer and sparser on clypeus, denser, larger and deeper in middle, punctation of infraorbital portions about as that in middle but slightly finer; neck with dense moderately large punctation; punctation of pronotum dense and large, sparser in middle, lateral and mediobasal portions; punctation of elytra dense, but larger and deeper than that on pronotum, finer and sparser in middle; abdominal tergites without visible punctation or with fine, sparse and fine punctation in middle (paratype from Kunashir). Anterior portion of clypeus with fine transverse microsculpture, laterobasal parts of clypeus with dense diagonal meshes, middle portion with indistinct or distinct and dense diagonal microreticulation, infraorbital portions with dense longitudinal microsculpture; neck with transverse sculpture, invisible in holotype and one parartype in middle; scutellum with fine isodiametric meshes; abdominal tergites with dense and moderately coarse isodiametric sculpture. Anterior portion of head with erect elongate setation, each mediolateral part of clypeus and mediobasal part of infraorbital portion with long erect seta; lateral portions of pronotum with several short setae; abdominal tergites with dense and very short setation; posterior margin of pronotum and elytra (two paratypes) with row of short cuticular fringe. Head 1.4 times as broad as long, with somewhat flattened (paratype from Kunashir) or slightly convex middle part and with distinctly elevated infraorbital portions; clypeus relatively wide, convex, with strongly explanated supra-antennal elevations; anteriomedian depressions relatively wide and deep, elongate, reaching level of anterior margin or anterior third of eyes; each posteriolateral margin of clypeus distinctly narrowed and stretching posteriad toward level of anterior third or middle of eye. Median part of head without or with fine irregular elevations between punctures, with three to four narrow elongate wrinkles on posterior parts of infraorbital portions. Anteocellar foveae suboval and deep, somewhat shortened or elongate and slightly convergent latero-apicad, reaching level of posterior third or middle of eyes. Temples short, strongly narrowed posteriad. Nuchal constriction moderately wide and deep. Ocelli large, located slightly below level of posterior margins of eyes; distance vetween ocelli 1.7 times to twice as long as distance between ocellus and posterior margin of eye. Antenna with slightly elongate antennomeres 4 – 7 and transverse 8 – 10; antennomere 4 short, slightly more than twice as long as 3, 5 indistinctly broader than 4, 6 slightly longer and broder than 5, 7 broader than 6, 8 broader than 7, 9 – 10 distinctly broader than 8, apical antennomere 1.3 – 1.4 times as long as preceding segment, from middle strongly narrowed toward subacute apex. Pronotum disitnctly convex, 1.5 – 1.6 times as broad as long, 1.5 – 1.6 times as broad as head, from widest middle more narrowed posteriad than anteriad toward obtuse hind angles. Anterior angles slightly narrowed toward relatively wide apical angles. Anterior margin widely rounded, slightly concave in middle, slightly shorter than rounded posterior margin. Lateral portions realtively widely impressed and distinctly explanate, each with deep elongate impressions behind middle. Surface of disc with two elongate longitudinal depressions, significantly deepened in mediobasal portion; each lateroapical portion with curvad elongate elevation, reaching middle of pronotum; surface between longidinal elevations slightly elevated. Elytra slightly broader than long, 1.9 times as long as pronotum, slightly broadened postreriad. Dorsal surface of each elytron (except median areas along suture) with moderately strong longirudinal elevations between punctures. Abdomen slightly narrower than elytra. Male. Posterior margin of abdominal tergite VIII straight. Posterior margin of abdominal sternite VIII straight or slightly rounded. Aedeagus with broadened basal portion, gradually narrowed toward middle; median lobe relatively narrow, elongate, from widest middle gradually narrowed toward small rounded apex, from above middle with narrow rounded lateral projections; parameres wide, significantly shorter than apex of median lobe, distinctly narrowed in apical portions, each with two long apical and one shorter preapical setae; internal sac narrow and long, with small paired oval sclerotized structures in basal portion (Fig. 29). Lateral aspect of the aedeagus as in Fig. 30; apical portion of median lobe (lateral view) with rounded apex, with several ventrolateral teeth, elongate basad, with largest ventrolateral tooth relatively long. Female. Posterior margins of abdominal tergite VIII and sternite VIII truncate. Accessory sclerite elongate, from widest basal portion gradually narrowed toward subacute apex (Fig. x). Spermatheca not recognized. Comparative notes. Based on general shape and coloration of the body, and shape of the aedeagus, O. kurilicum sp. nov. is similar to O. pseudojaponicum Shavrin, 2025, recently described from Gansu, China (Shavrin 2025). It can be distinguished from it by the more elongate antennomere 7, denser punctation of the pronotum, shape of the slightly broader pronotum, more narrowed posteriad than anteriad, shape of shorter and broader median lobe of the aedeagus and slightly different shapes of ventrolateral teeth on it, and other details of the morphology of the aedeagus.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958327BC5B8BE0904C0FE2FABC.taxon	distribution	Distribution. Omalium kurilicum sp. nov. is known from two localities in Iturup and Kunashir islands, Kuril islands, Russia (Fig. 16).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958327BC5B8BE0904C0FE2FABC.taxon	etymology	Etymology. The specific epithet derived from the type locality (Kuril islands) of the species.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958327BC5B8BE0904C0FE2FABC.taxon	biology_ecology	Bionomics. Detailed bionomical data are unknown.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958327BC5B8BE0904C0FE2FABC.taxon	discussion	Remarks. Shavrin & Makarov (2019) recorded it as “ Omalium sp. ” for Kunashir Island (see material above).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958326BC558BE0947C09E8F808.taxon	description	(Figs 32, 35, 38 – 40)	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958326BC558BE0947C09E8F808.taxon	materials_examined	Type material examined. Holotype ♂ (Fig. 35): ‘ Type’ <round label with red margin, printed>, ‘ Japan. [underlined by yellow] | G. Lewis. | 1910 - 320. ’ <printed>, ‘ Kurigahara. | 4. VIII. – 6. VIII. [18] 81. ’ <printed>, ‘ Omalium | niponense | Type D. S. ’ <handwritten in black>, ‘ NHMUK 015009855 ’ <printed label with barcode on the right side>, ‘ Omalium | niponense Sharp, 1889 | Shavrin A. V. det. 2025 ’ <printed> (BMNH). Material examineD. JAPAN: HONSHU: 1 ♂: ‘ Futamata Shimashimadani Shimshiu 21 - July- 1936 Coll. Y. Yano’, ‘ No. 2653 Collection Yoshio Yano’, ‘ O. niponense Shp. ’, ‘ M. Cameron. Bequest. B. M. 1955 - 147. ’ (BMNH); RUSSIA: MARITIME PROVINCE: 2 ♂♂: Sikhote-Alin Nature Reserve, Kabaniy Klyuch, 45 ° 07 ’ N 135 ° 52 ’ E. 500 m a. s. l., window traps. 24 – 27.04.2015. D. E. Shcherbakov leg. (cR, cSh).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958326BC558BE0947C09E8F808.taxon	description	Redescription. Measurements (n = 4): HW: 0.60 – 0.70; HL: 0.40 – 0.45; OL: 0.15 – 0.16; TL: 0.07 – 0.10; AL (holotype): 1.17; PL: 0.47 – 0.52; PWmax: 0.73 – 0.82; PWmin: 0.68 – 0.70; ESL: 0.86 – 1.10; EW: 0.95 – 1.12; MTbL (holotype): 0.45; MTrL (holotype): 0.25 (MTrL 1 – 4: 0.10; MTrL 5: 0.15); AW: 0.97 – 1.13; AedL: 0.55 – 0.62; BL: 3.17 (holotype) – 3.70. Habitus as in Fig. 35. Body yellowish-brown to reddish-brown, usually with slightly paler lateral and basal portions of pronotum, elytra and paratergites of abdomen; antennomeres 5 – 11 or 6 – 11 brown; mouthparts, antennomeres 1 – 4 or 1 – 5 and legs yellowish to yellow-brown (tarsi sometimes paler). Punctation of head variable, fine or moderately large, sparse or dense, usually denser in middle; neck with sparse fine punctation; punctation of pronotum about as that in middle portion of head, by slightly larger, usually finer and sparser in middle and mediobasal portion (specimens from Russia with significantly denser and more regular punctation); punctation of elytra denser, larger and deeper than that on pronotum; abdominal tergites with sparse and fine, sometimes indistinct, punctation. Anterior portion of clypeus with fine transverse microsculpture; scutellum without or with fine isodiametric meshes; abdominal tergites with dense isodiametric microsculpture. Anterior portion of clypeus with several erect long setae; posterior margin of pronotum and sometimes posterior margins of elytra with short cuticular fringe. Head 1.5 times as broad as long, flattened or slightly elevated in middle, with widely broadened clypeus and strongly elevated, distinctly explanate supra-antennal elevations; anteriomedian depressions wide and deep, reaching level of anterior third of eyes; posteriolateral margins of clypeus somewhat parallel-sided or slightly narrowed basad, reaching level of anterior third of eyes. Mediodorsal surface with irregular diagonal elevations between punctures in middle and with longitudinal elevations on posterior parts of infraorbital portions, postocular portions sometimes forming three to four narrow, sometimes indistinct, elongate wrinkles. Anteocellar foveae suboval, deep and slightly elongate, convergent lateroapicad toward level of posterior third or middle of eyes. Temples 1.6 times to twice as long as longitudinal length of eye. Distance between ocelli 1.5 – 1.8 times as long as distance between ocellus and posterior margin of eye. Antenna with elongate antennomeres 6 – 8 and transverse 9 – 10; antennomeres 6 – 7 indistinctly broader than 5, 8 slightly shorter than 7, 9 – 10 slightly broader than 8, apical antennomere 1.3 – 1.5 times as long as preceding segment. Pronotum convex, 1.5 times as broad as long, 1.1 – 1.2 times as broad as head, from widest middle more narrowed posteriad than anteriad. Surface of disc with two elongate, shallow or deep, longitudinal depressions; medioapical depression mising or present, small and shallow; surface between all pronotal depressions slightly or strongly elevated. Middle portion sometimes with irregular indistinct or distinct transverse and diagonal elevations between punctures. Elytra slightly broader than long, 1.8 times to more than twice as long as pronotum, distinctly broadened posteriad. Male. Posterior margin of abdominal tergite VIII straight or rounded. Posterior margin of abdominal sternite VIII slightly sinuate. Aedeagus with broadened basal portion, gradually narrowed toward middle; median lobe moderately wide, from widest middle gradually narrowed toward small rounded apex; mediolateral portions with short and relatively wide accessory plates, each rounded apically; parameres moderately narrow, significantly shorter than apex of median lobe, slightly curved and narrowed in preapical portion, each with one long and one short apical and two short preapical setae; internal sac narrow and long, with paired oval structures in basal portion (Figs 38 – 39). Lateral aspect of the aedeagus as in Fig. 40; apical portion of median lobe narrow, with small rounded apex. Female unstudied. Comparative notes. Based on coloration and shape of the habitus and the aedeagus, O. niponense is similar to O. flavotestaceum Shavrin, 2023, recently described from West Bengal, India (Shavrin 2023). It can be distinguished from it by the shape of the pronotum widest in middle, the shape of the shorter and broader median lobe, the narrower parameres, and other details of the morphology of the aedeagus.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958326BC558BE0947C09E8F808.taxon	distribution	Distribution. Omalium niponense is known from Maritime Province (Russia) and Japan (Fig. 32).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958326BC558BE0947C09E8F808.taxon	biology_ecology	Bionomics. Detailed bionomical data from Japan are unknown, except for specimens collected in Ehime University Forest (Ishihara et al. 1974), which were sifted under leaves. Specimens from Sikhote-Alin Nature Reserve were collected at an altitude of 500 m a. s. l. by window traps.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B87958326BC558BE0947C09E8F808.taxon	discussion	Remarks. Omalium niponense was originally described based on a single specimen from “ Kashiwagi, 23 rd June, 1881 … ”. Watanabe (1990) redescribed it and provided additional material from Hokkaido, Honshu, Shikoku and Kyushu. Specimens from Maritime Province are slightly narrower than Japanese specimens. Besides that, they have denser punctation of the forebody, but the morphology of the aedeagus is without significant differences (Figs 38, 40). It is here recorded from Amur Area and Russia for the first time.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795832BBC568BE091B50FE0FBB4.taxon	materials_examined	Material examined. KHANTY-MANSI AUTONOMOUS REGION: 1 ♂: Surgutskiy District, Yuganskiy Nature Reserve, Basin of Ay-Magromsy River, “ Medvezhiy Ugol ” cordon. In geophilous and epigenous gill fungi (+ 12 ° C). 16.09.2002. A. B. Ryvkin leg. (ZMM); TOMSK AREA: 1 ♂, 2 ♀♀: Tomsk, Tom` River. 15.09.2011. M. I. Kukshinova leg. (cSh); NOVOSIBIRSK AREA: 4 ♂♂, 3 ♀♀: Novosibirsk, Akademgorodok-Klyuchi. Aspen forest, carrion, traps. 12 – 14.09.2008. V. K. Zinchenko leg. (cSh); 8 ♂♂, 6 ♀♀: same data. Mixed forest, carrion, traps. 21 – 27.09.2008. (cSh); 3 ♂♂, 1 ♀: same data, 27 – 31.08.2008. (cSh); 2 ♂♂, 1 ♀: same data, 03 – 05.10.2008. (cSh); 1 ♂: same data, environs of Akademgorodok. Carrion traps. 28.09 – 11.10.2008. V. K. Zinchenko leg. (cSh).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795832BBC568BE091B50FE0FBB4.taxon	discussion	Remarks. Omalium rivulare is a widely distributed species in the Holarctic region (Schülke & Smetana 2015). It was recorded from Sverdlovsk Area (Belskaya & Kolesnikova 2011; Ermakov et al. 2017), and Tyumen Area (Bukhkalo et al. 2012). It also was recorded from Krasnoyarsk Territory (Shavrin 2010), but was misidentified and belongs to O. caesum. Records of the species from Yakutia (Averenskiy 1999, 2003) and Maritime Province (Kryzhanovskiy et al. 1973) require confirmation. It is also known from the northern regions of Russia west of Ural Mts. (e. g. Kolesnikova 2000). It is here recorded from Khanty-Mansi Autonomous region, Tomsk and Novosibirsk areas from the first time.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795832BBC568BE0956E0FF1FA78.taxon	description	(Fig. 41)	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795832BBC568BE0956E0FF1FA78.taxon	materials_examined	Type material examined. Paratype ♀ (Fig. 41): ‘ MONGOLIA: Chövsgöl aimak | 3 km SW von Somom Buren- | chaan, 1650 m | Exp. Dr. Z. KASZAB, 1968 ’ <printed>, ‘ Nr. 993 | 21. VI. – 16. VII. 1968 ’ <printed>, ‘ PARATYPE | Omalium [handwritten in black] | scabrum m. [handwritten in black] | A. Smetana [printed] 1973 [handwritten in black] | CNC. No. [printed] 13286 [handwritten in black] ’ <yellow, printed> (CNC).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795832BBC568BE0956E0FF1FA78.taxon	discussion	Remarks. Omalium scabrum was originally described from Mongolia. Based on the shape of the median lobe, it refers to the Rivulare group (Zanetti 1987). The habitus of this species is illustrated for the first time (Fig. 41).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795832BBC508BE097390937F9D2.taxon	description	(Figs 18, 42, 48 – 49)	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795832BBC508BE097390937F9D2.taxon	materials_examined	Material examined. KHANTY-MANSI AUTONOMOUS REGION: 1 ♀: Yuganskiy Reserve (buffer zone), flood-plain of a rill (confluent of Malyi Yugan River) near Achimovy- 2 village, tussocks of Carex spp. and Poaceae, depressions with Carex rostrata, Filipendula ulmaria, Comarum palustre, Urtica dioica, Sphagnum centrale, Climacium dendroides, Plagiomnium sp., Rubus saxatilis, Salix sp., sparse Betula and Picea. 24.08.2003. A. B. Ryvkin leg. (cSh); 1 ♀: Surgutskiy District, near Ugut, basin of Ugutka River. In geophilous fungi. 20.08.1998. A. B. Ryvkin leg. (cR); 1 ♀: same District, Yuganskiy Reserve, Malyi Yugan River, near cordon up-stream of mouth of Lyarykni River. In geophilous and arboreal gill fungi in forest. 15.08.2003. A. B. Ryvkin leg. (ZMM); 1 ♀: same District and Reserve, Basin of Ay-Magromsy River, “ Medvezhiy Ugol ” cordon. In geophilous and arboreal gill fungi (+ 12 ° C). 16.09.2002. A. B. Ryvkin leg. (ZMM); TYUMEN AREA: 1 ♀: Uvatskiy District, 10 km S Gornoslinkino, near Tobolsk Field Research Station of Severtsov Institute. Litter and mosses under Abies, Betula, Tilia with Maianthemum, grasses, Oxalis etc. on a steep slope at bank of Irtysh River up-stream mouth of Missiinka River. 10.09.2003. A. B. Ryvkin leg. (ZMM); KRASNOYARSK TERRITORY: 3 ♂♂, 6 ♀♀: Turukhanskiy Distrtict, upper reaches of Nizhnyaya Lebedyanka River. 21.06.1992. V. B. Semenov leg. (cSh, ZMM); 1 ♀: same data, 3 km up-stream of mouth. 17 – 18.08.1992. V. B. Semenov leg. (cSh); 1 ♀: same data, up-stream of Nizhnyaya Lebedyanka River. 18.06.1992. V. B. Semenov leg. (ZMM); 2 ♂♂, 4 ♀♀: same data. Evening flying near water and trap with rotten fungi etc. 17.06.1992. (cSh, ZMM); 4 ♀♀: same data. Trap with rotten potato at bank of the river. 18.06.1992. (ZMM); 2 ♂♂, 4 ♀♀: same data. Trap with cow dung in forest with Pinus sibirica. 19.06.1992. (cSh, ZMM); 1 ♂: same District, Nizhnyaya Sarchikha near Kamenka River mouth. 150 – 200 m a. s. l. 08 – 11.07.1992. V. B. Semenov leg. (cR); 1 ♂: same District, Bor. 40 m a. s. l., collected on the fly. 14.05.1992. V. B. Semenov leg. (cR); 1 ♀: same District, Yeloguy Nature Refuge, Yeloguy River, 6 km below Tyna R., mouth. Under mosses with dog excrements in forest with Pinus sylvestris. 29.07.1992. V. B. Semenov leg. (ZMM); 1 ♂, 1 ♀: same District, Central Siberian Biosphere Reserve, Bol`shaya Varlamovka River basin, middle reaches of Bol`shaya Raskosaya River. Swamp with Sphagnum spp., Oxycoccus sp., Betula? nana, dead grass. 23.05.1992. V. B. Semenov leg. (ZMM); 1 ♀: Baykitskiy District, Central Siberian State Resrve, Stolbovaya River basin: lower reaches of Birapchana River near mouth of Kruten’kiy Stream. 110 m a. s. l., loamy river bank with Salix sp., dead Poaceae gen. spp. etc., in drift. 23.06.1993. V. B. Semenov leg. (cSh); 2 ♂♂, 2 ♀♀: Yermakovskiy District, Sayano-Shushenskiy Nature Reserve, Bolshiye Ury River, 4 km up-stream of Ottug-Suuk River mouth. 860 m a. s. l., horse dung on the forest trail. 18.05.1989. A. B. Ryvkin leg. (cR); 1 ♀: same District, valley of Us River, 152 th km of Kyzyl-Abakan route, gorge of stream (right tributary of Us River). Sphagnum spp., sparse Salix sp., Picea obovata, grasses, Equisetum sp. (He + Hm?). 13.08.1984. A. B. Ryvkin leg. (ZMM); EVENKIA: 1 ♂, 1 ♀: Baykitskitskiy District, Podkamennaya Tunguska River, 235 km up-stream of mouth, mouth of Khagdasis River. Litter and mosses on a steep rock slope with Picea, Pinus sibirica, Betula, Abies, Pyrola, Majanthemum, Linnaea, Vaccinium citis-idaea etc. 19.08.1990. A. B. Ryvkin leg. (cSh); 1 ♀: same District, Central Siberian Biosphere Reserve, Podkamennay Tunguska River, Stolbovaya River mouth. In gill and arboreal fungi. 11.09.1988. A. B. Ryvkin leg. (cR); 1 ♂, 1 ♀: same Reserve, Stolbovaya River basin: lower reaches of Birapchana River near mouth of Kruten’kiy Stream. 110 m a. s. l, loamy river bank with Salix sp., dead Poaceae gen. spp., etc., in drift. 23.06.1993. V. B. Semenov leg. (cSh); TUVA: 1 ♂: Todzhenskiy District, Toora-Khem village. 900 m a. s. l. Evening flying in the yard and in the garden. 04.06.1992. A. B. Ryvkin leg. (cSh); BURYATIA: 1 ♀: Okinskiy District, valley of Khelgin River, 52 ° 31.132 ’ N 98 ° 49.449 ’ E. 2172 m a. s. l. 23.06.2017. I. V. Enushchenko leg. (cSh); 1 ♂: Bauntovskiy District, Baysa, bank of Vitim River. Under stone. 11.08.1969. V. V. Zherikhin leg. (cR); 1 ♀: same District, Vitim River basin, Romanovka. 17.06.1969. A. P. Rasnitsyn & V. V. Zherikhin leg. (cR); YAKUTIA: 1 ♂, 1 ♀: Srednekolymsk. 12.07 – 10.08.1991. S. K. Alekseev leg. (cSh); AMUR AREA: 1 ♀: Skovorodinskiy District, left side of Urka River, about 4 km N Yerofey Pavlovitch, 54 ° 00 ’ 40.89 ’’ N 121 ° 57 ’ 43.75 ’’ E. 525 m a. s. l. 26 – 28.08 – 02 – 03.09.2014. A. V. Shavrin & I. V. Enushchenko leg. (cSh); 1 ♂: Selemdzhinskiy 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); 1 ♂: same District, Byssa River basin, bottom part of mountainside NW of “ Tyoplyi Klyuch ” spa, 380 m a. s. l., evening flight. 22.06.2007. E. M. Veselova & A. B. Ryvkin leg. (ZMM); KHABAROVSK TERRITORY: 3 ♂♂, 3 ♀♀: Verkhnebureinskiy District, near Niman cordon of Bureinskiy Nature Reserve, N 52 ° 08.48 ’ E 134 ° 13.54 ’, 1035 m a. s. l., mushroom bait (flotation). 18.08.2008. A. B. Ryvkin leg. (cR, cSh); 1 ♀: same District, Bureinskiy Nature Reserve near “ Strelka ” cordon, 560 m a. s. l., in geophilous gill fungi, moss and leaf litter under those. 15.09.2006. A. B. Ryvkin leg. (cR); 1 ♀: same 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. (cR); MARITIME PROVINCE: 1 ♂: Sikhote-Alin Nature Reserve, Kabaniy Klyuch, 45 ° 07 ’ N 135 ° 52 ’ E. 500 m a. s. l., window traps. 24 – 27.04.2015. D. E. Shcherbakov leg. (cR).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795832BBC508BE097390937F9D2.taxon	discussion	Remarks. The Holarctic O. strigicolle is widely ditributed in eastern Siberia and Russian Far East (Schülke & Smetana 2015). It was recorded from Irkutsk Area (Anishchenko & Shavrin 1998; Shavrin 2010), Buryatia (Ananina & Voincov 2006), Yakutia (Poppius 1904 b), Magadan Area (Ryabukhin 1999, 2002), Kamchatka Territory (Lobkova & Semenov 2014; Lobkova et al. 2017) and Commander islands (Sazhnev 2018). Shavrin (2010) misidentified some specimens of this species, which are actually O. caesum, from Turukhanskiy District of Krasnoyarsk Territory. All specimens from Irkutsk and Chita areas provided by Shavrin (2010) as O. subsolanum were misidentified and belong to O. strigicolle. Smetana (1968) recorded it from Mongolia. Habitus as in Fig. 42. Aedeagus as in Figs. 48 – 49. Female accessory sclerite as in Fig. 18. It is here recorded from Khanty-Mansi Autonomous Region, Tyumen Area, Krasnoyarsk Territory, Evenkia, Tuva, Amur Area and Khabarovsk Territory for the first time.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795832DBC538BE0978809FFFC30.taxon	description	(Figs 19, 21, 43, 44 – 47)	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795832DBC538BE0978809FFFC30.taxon	materials_examined	Type material examined. Lectotype (here designated) of O. clavatum Luze, 1906 ♀ (Fig. 43): ‘ ♀ ’ <printed>, ‘ Ost-Sibir. | Irkut’ <handwritten in black>, ‘ ex. coll. | Luze’ <yellow printed> ‘ TYPUS [printed] | Omalium | clavatum | Luze’ <red, handwritten in black>, ‘ LECTOTYPE | Omalium | clavatum Luze, 1906 | Shavrin A. V. des. 2025 ’ <red, printed>, ‘ Omalium | subsolanum Herman, 2001 | Shavrin A. V. det. 2025 ’ <printed> (NMW). Paralectotype ♀: same four labels as those in the lectotype, but with additional printed label: ‘ Omalium | subsolanum Herman, 2001 | Shavrin A. V. det. 2025 ’ (NMW). Material examined. RUSSIA: BURYATIA: 1 ♂: ‘ Ost-Sibirien Quellgebiet des Irkut Leder 1891 ’, ‘ oxyacanthae Grv. ’, ‘ c. Eppelsh. Steind. d. ’, ‘ clavigerum m. det. Luze’, ‘ CO-TYPUS’ (NMW); 1 ♀: ‘ Ost. Sibirien’, ‘ c. Eppelsh. Steind. d. ’, ‘ clavigerum m. det. Luze’, ‘ CO-TYPUS’ (NMW); 1 ♂: ‘ oxyacanthae Grv. ’, ‘ Ost-Sibirien Quellgebiet des Irkut Leder 1891 ’, ‘ c. Eppelsh. Steind. d. ’, ‘ clavigerum m. det. Luze’, ‘ CO-TYPUS’ (NMW); AMUR AREA: 1 ♀: Zeyskiy District, Zeya Nature Reserve, cordon 52 km. 12.07.1978. V. V. Belov & S. A. Kurbatov leg. (cSh); JAPAN: HONSHU: 1 ♂, 1 ♀: Yamanashi Prefecture, Kitazawatoge Pass, Ashiyasu-mura. 15 – 20.07.2001. T. Ueno leg. (cSch).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795832DBC538BE0978809FFFC30.taxon	description	Redescription. Measurements (n = 11): HW: 0.41 – 0.48; HL: 0.29 – 0.33; OL: 0.11 – 0.15; TL: 0.04 – 0.06; AL (holotype): 0.70; PL: 0.33 – 0.38; PWmax: 0.50 – 0.56; PWmin: 0.48 – 0.53; ESL: 0.63 – 0.73; EW: 0.70 – 0.73; MTbL (holotype): 0.30; MTrL (holotype): 0.18 (MTrL 1 – 4: 0.08; MTrL 5: 0.10); AW: 0.70 – 0.76; AedL: 0.45; BL: 1.90 – 2.60 (lectotype: 2.45). Habitus as in Fig. 43. Body reddish-brown, with distinctly paler elytra; antennomeres 6 – 11 brown; mouthparts, antennomeres 1 – 5 and legs yellow. Punctation of head moderately dense and finer, denser in middle; neck with moderately dense or sparse fine punctation; punctation of pronotum dense, slightly larger than that in middle of head, sparser in middle, lateral and mediobasal portions; punctation of elytra about as that on pronotum, but slightly larger, sparser in middle; abdominal tergites with indistinct and relatively dense fine punctation. Anterior part of clypeus with dense transverse microreticulation, laterobasal parts of clypeus with distinct transverse or subdiagonal meshes, middle part without or with traces of fine diagonal or longitudinal meshes, infraorbital portions with distinct longitudinal microsculpture; neck with fine and dense transverse sculpture, sometimes invisible in middle; scutellum with dense isodiametric or transverse microreticulation; abdomen with dense isodiametric sculpture. Anterior portion of clypeus with several erect and relatively short setae; abdominal tergites with dense, short and sometimes indistinct setation; posterior margin of pronotum with row of short cuticular fringe. Head 1.4 times as broad as long, slightly elevated in middle and distinctly elevated in infraorbital portions, with broad clypeus and distinctly explanated supra-antennal elevations; anteriomedian depressions moderately wide and deep; each posteriolateral margin of clypeus slightly narrowed basad and reaching level of about middle of eye. Mediodorsal surface with fine transverse or diagonal elevations between punctures in middle, with elongate narrow and sometimes indistinct elevations along each infraorbital portion. Anteocellar foveae somewhat suboval, deep and elongate, convergent latero-apicad toward level of posterior third or about middle length of eye. Temples short, gradually narrowed toward neck. Nuchal constriction moderately wide and deep. Ocelli moderately large, located slightly behind level of posterior margins of eyes; distance between ocelli 1.3 – 1.4 times as long as distance between ocellus and posterior margin of eye. Antenna with distinctly transverse antennomeres 6 – 8 and slightly transverse 9 – 10; antennomeres 4 – 5 shorter than 3, 6 slightly shorter than 5, 7 slightly longer than 6, 8 distinctly shorter and slightly broader than 7, 9 – 10 longer and broader than 8. Pronotum 1.4 – 1.5 times as broad as long, 1.1 – 1.2 times as broad as head, from widest middle slightly more narrowed posteriad than anteriad. Apical angles broadely widened, not protruded anteriad. Anterior margins slighty rounded, sometimes slightly concave in middle. Lateral portions relatively widely impressed, with moderately broad impressions behind middle. Surface of disc with two elongate shallow or relatively deep longitudinal depressions, broadened basad, without or with shallow small medioapical depression; each lateroapical portion with indistinct or distinct curved and narrow elevation, reaching about middle of pronotum. Middle portion sometimes with irregular and fine diagonal elevations between punctures. Elytra slightly narrower or about as broad as long, 1.9 times as long as pronotum, slightly broadened posteriad; lateral portions relatively widely impressed. Dosrsal surface of each elytron with irregular and distinctly elevated longitudinal elevations between punctures in middle. Metatarsi less than twice as long as metatibia. Abdomen about as broad as or slightly broader than elytra. Male. Posterior margin of abdominal tergite VIII straight or slightly concave. Aedeagus with wide basal portion, slightly narrowed toward middle; median lobe narrow, from widest middle strongly narrowed toward elongate preapical portion with small rounded or subacute apex; mediolateral portions with relatively short accessory plates, each rounded apically; parameres wide, reaching level of preapical part of median lobe, distinctly narrrowed in apical portions, with two long apical and two relatively short preapical setae; internal sac wide and long, with paired oval structures in basal portion (Figs 44, 46). Lateral aspect of the aedeagus as in Figs 45, 47; apical portion of median lobe slightly broadened, with rounded apex, slightly crenulated ventroapically. Female. Posterior margin of abdominal tergite VIII straight. Posterior margin of abdominal sternite VIII slightly rounded. Accessory sclerite elongate, from widest basal portion gradually narrowed toward small rounded apex (Fig. x). Spermatheca not recognized. Comparative notes. Based on the general shape and coloration of the body, proportions of antennomeres, and the general shape of aedeagus and female accessory sclerite, O. subsolanum is similar to O. diffine (see above), from which it can be distinguished by the slightly broader pronotum, shorter median lobe without rounded lateral projections in the middle, shape of the apical part of the median lobe (lateral view) without hook in preapical part, and other details of the morphology of the aedeagus.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795832DBC538BE0978809FFFC30.taxon	distribution	Distribution. Omalium subsolanum is known from several localities in Siberia, Russian Far East (Amur Area) and Japan (Honshu) (Fig. 21).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795832DBC538BE0978809FFFC30.taxon	biology_ecology	Bionomics. Detailed bionomical data are unknown.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795832DBC538BE0978809FFFC30.taxon	discussion	Remarks. Omalium clavatum was originally described based on an unspecified number from “ Ostsibirien (Quellgebiet des Irkut) ”. I designate here the female with the best preservation (Fig. 43) as the lectotype in order to fix the identity of the name. Herman (2001 b) provided a new name for it due the homonymy with O. clavatum Fauvel, 1869. Omalium subsolanum is known from Irkutsk Area (Shavrin 2010) and Buryatia (Luze 1906). Eppelsheim (1893) recorded it from the valley of Irkut River (it was identified as O. oxyacanthae; see material above). The record of O. clavatum from the environs of Novosibirsk by Schawaller (1990) require confirmation. It is here recorded from Amur Area and Japan for the first time.	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
F91B8795832EBC538BE095380E6AFAB3.taxon	discussion	Remarks. The Nearctic Omalium foraminosum is known from USA and Canada (Herman 2001 a). Eppelsheim (1893) erroneously recorded “ zwei Ex. ” from ‘ Quellgebiet des Irkut’ (Buryatia).	en	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): 199-235, DOI: 10.11646/zootaxa.5646.2.2, URL: https://doi.org/10.11646/zootaxa.5646.2.2
