( Fig. 2A, B)
Stenus ( Nestus) raddei Ryvkin, 1987: 156.
Stenus raddei – Herman 2001: 2365.
Stenus ( Nestus) raddei – Naomi & Puthz 1994: 219.
Stenus (s. str.) raddei – Smetana 2004: 561.
RUSSIA: 1 ♀, Maritime Province, Lazovskiy Nature Reserve, 10 km W of Preobrazheniye, swampy meadow, t=20°, pH=5.4, 17 Aug. 1986, A. Shatrovskiy leg. ( AR); 1 ♂, Amur Province, Selemdzhinskiy District, near Selemdzhinsk, 270–280 m a.s.l., 12 Aug. 1976, E.M. Veselova & A.B. Ryvkin leg. ( AR); 1 ♀, Amur Area, Selemdzhinskiy District, Norskiy Reserve, near Fevral’sk, 268th km of Belogorsk- Fevral’sk road, Tikhiy rill, 275 m a.s.l., mosses and plant debris between sedge & gramineous tussocks among Alnus sp., Salix sp., Spiraea sp. with Sphagnum squarrosum, Sph. spp., etc., 8 Oct. 2008, A.B. Ryvkin leg. <?> ( AR); 3 ♂♂, 4 ♀♀, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve, Selemdzha River basin near Dvadtsatikha cordon, open swamp: Carex sp., Spiraea spp., Geranium sp., Vicia sp., Poaceae gen. sp., Salix spp., Filipendula palmata, sparse Plagiomnium sp., Sphagnum sp., Polytrichum sp., etc., 4 Aug. 2004, A.B. Ryvkin leg. ( AR); 1 ♀, same locality, mosses and plant debris among tussocks at small open swamp with Carex spp. and Poaceae gen. sp., 10 Aug. 2004, A.B. Ryvkin leg. ( AR); 3 ♂♂, 3 ♀♀, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve, Selemdzha River basin, 1.5 km NE of Dvadtsatikha cordon, banks and burnt flood-plain of a rill inflowing to lake, 222 m a.s.l., mosses and leaf litter among Carex spp., Alnus sp., Salix spp., Padus sp., undergrowth of Betula spp. and Populus tremula, etc., 18 Aug. 2006, E.M. Veselova & A.B. Ryvkin leg. ( AR); 6 ♂♂, 4 ♀♀, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve, Selemdzha River basin, 2 km NE of Dvadtsatikha cordon, open swamp near lakeside: plant debris and sparse mosses among tussocks with Carex spp., Poaceae gen. sp., Salix spp., etc., 9 Aug. 2004, A.B. Ryvkin leg. ( AR, ShIN); 4 ♂♂, 3 ♀♀, Amur Area, Selemdzhinskiy District, Selemdzha River basin, flood-plain of Aldikon River near Norsk, mosses and leaf litter under Salix sp. and along the edge of open sedge-gramineous tussock swamp, 5 Sep. 2004, A.B. Ryvkin leg. ( AR, LH); 11 ♂♂, 21 ♀♀, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve, Nora River basin near Maltsevskiy cordon, mosses and plant debris on swampy floodplain lakeside: Carex spp., Calamagrostis sp., Filipendula palmata, Geranium sp., Comarum palustre, Spiraea sp., Salix sp., Sphagnum? girgensohnii, Sph. squarrosum, Polytrichum commune, P. sp., Climacium sp., Iris sp., etc., 28 Aug. 2004, A.B. Ryvkin leg. ( AR); 1 ♂, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve, rill (left confluent of Nora River) up-stream of Gryashchinskaya Mt., true mosses and plant debris among Carex spp., Poaceae gen. sp., Alnus sp., Padus sp., Salix sp., etc., 26 Aug. 2004, A.B. Ryvkin leg. ( AR); 7 ♂♂, 3 ♀♀, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve, Nora River basin, 1.5 km up-stream of Gryashchinskaya Mt., mosses and plant debris on open swamp along lake side: tussocks of Carex spp. and Poaceae with Sphagnum? girgensohnii, Sph.? angustifolium, Sph.? magellanicum, Sph. squarrosum, Sph. spp., Chamaedaphne calyculata, Vaccinium uliginosum, sparse Ledum palustre, Salix sp., Betula? fruticosa, etc., 24 Aug. 2004, A.B. Ryvkin leg. ( AR); 1 ♂, 3 ♀♀, same locality, moss and plant debris on Carex - Eriophorum swamp with Chamaedaphne calyculata, gramineous admixture, Comarum palustre, Salix sp., Vaccinium uliginosum, Sphagnum spp., etc., 25 Aug. 2004, A.B. Ryvkin leg. ( AR); 3 ♂♂, 9 ♀♀, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve, Nora River basin, 2 km up-stream of Gryashchinskaya Mt., mosses and plant debris on small open swamp on high flood-plain: tussocks of Calamagrostis sp. and Carex spp. with Sphagnum? girgensohnii, Sph. squarrosum, Sph. centrale, Sph. spp., Rubus arcticus, Convallaria keiskei, Salix sp., etc., 22 Aug. 2004, A.B. Ryvkin leg. ( AR); 3 ♂♂, 1 ♀, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve, Nora River basin near Meunskiy cordon, mosses and plant debris among Carex spp. & Poaceae with Comarum palustre, Sphagnum squarrosum, Sph. spp., Aulacomnium sp. and other true mosses near side of flood-plain lake and swampy road, 13 Aug. 2004, A.B. Ryvkin leg. ( AR); 1 ♂, same locality, swamp with sedge tussocks, Poaceae gen. sp., Sphagnum squarrosum, Sph. spp., etc., 14 Jul. 2005, A.B. Ryvkin leg. ( AR); 3 ♂♂, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve, Nora River basin near Meun River mouth, small swamp with Carex spp., Poaceae & Sphagnum squarrosum, 19 Aug. 2004, A.B.Ryvkin leg. ( AR); 2 ♂♂, 5 ♀♀, same locality & biotope, 20 Aug. 2004, A.B. Ryvkin leg. ( AR); 1 ♀, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve, Meun River mouth, plant debris among Carex spp. & Equisetum sp. and leaf litter under Salix spp. & Alnus sp. on low bank of creek, 21 Aug. 2004, A.B. Ryvkin leg. ( AR); 1 ♂, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve, Burunda River bank 3 km up-stream of mouth, 215 m a.s.l., mosses and plant debris among sedges etc. and on shingle bed, 3 Aug. 2006, E.M.Veselova & A.B. Ryvkin leg. ( AR); 1 ♀, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve, Burunda River near Ozyornyi Rill mouth, mosses and plant debris among sedge-gramineous tussocks on very gentle slope near intermittent channel: Carex spp., Calamagrostis sp., Polytrichum sp. and other true mosses, Spiraea sp., etc., 27 Sep. 2004, A.B. Ryvkin leg. ( AR); 2 ♂♂, 3 ♀♀, same locality & biotope. 28 Sep. 2004, A.B. Ryvkin leg. ( AR); 5 ♂♂, 1 ♀, same locality, plant debris and mosses among tussocks of Carex spp. and Poaceae with Spiraea sp., Vicia sp., small true mosses, etc. on gently sloping side of small flood-plain lake, 2 Oct. 2004, A.B. Ryvkin leg. ( AR); 22 ♂♂, 2 ♀♀, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve (buffer zone), Burunda River basin, 1.5–2 km NW of Burunda cordon, mosses and plant debris on swamp and among sedge-gramineous tussocks in sparse growth of burnt Betula platyphylla and Larix gmelinii near Kamyshovoye Lake with Chamaedaphne calyculata, Comarum palustre, Vaccinium uliginosum, Ledum palustre, Sphagnum spp., Polytrichum sp., Hypnum sp., etc., 19 Sep. 2004, A.B. Ryvkin leg. ( AR); 1 ♀, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve (buffer zone), Burunda River basin, 1.5 km NW of Burunda cordon, sedge-gramineous swamp near rill, and also mosses and leaf litter among Carex spp. and under Alnus sp. on rill bank, 10 Sep. 2004, A.B. Ryvkin leg. ( AR); 1 ♀, same locality, plant debris among Carex sp. under sparse Alnus sp. with young growth of Larix gmelinii along rill bank near road, 18 Sep. 2004, A.B. Ryvkin leg. ( AR); 1 ♀, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve (buffer zone), Burunda River basin, 0.5–1 km NW of Burunda cordon, plant debris and small true mosses among Carex spp. & Poaceae (+sweeping) along rill bank, 12 Sep. 2004, A.B. Ryvkin leg. ( AR); 3 ♀♀, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve (buffer zone), Burunda River basin near Burunda cordon, plant debris and mosses (+sweeping) on swampy sides of flood-plain lake: Carex spp., Poaceae gen. sp., Spiraea sp., sparse Climacium sp., Hypnum sp., Sphagnum sp., Polytrichum sp., etc., 9 Sep. 2004, A.B. Ryvkin leg. ( AR); 1 ♂, 3 ♀♀, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve (buffer zone), Burunda River basin, 1 km SE of Burunda cordon, mosses and plant debris among sedge tussocks on wide Carex - Eriophorum -gramineous swamp with small true mosses, Sphagnum squarrosum, Sph. sp., Ledum palustre, Vaccinium uliginosum, sparse Salix sp., young growth of Betula sp., etc., 21 Sep. 2004, A.B. Ryvkin leg. ( AR); 1 ♀, Amur Area, Selemdzhinskiy District, Norskiy Nature Reserve (buffer zone), Burunda River basin, 2.5 km SE of Burunda cordon, small true mosses and plant debris among Carex spp. on sand, small shingles and clay along dried ephemeral stream near border of complex swamp, 21 Sep. 2004, A.B. Ryvkin leg. ( AR); 1 ♀, Khabarovsk Territory, Okhotsk, Airport, litter in larch forest, 15 Jul. 1987, V.V.Zherikhin & I.D.Sukacheva leg. ( AR); 1 ♀, Khabarovsk Territory, Okhotskiy District, Khetana River (confluent of Amka River, Ulya River basin), 7 km up-stream of river mouth, 31 Jul. 1985, V. Zherikhin, A. Rasnitsyn & D. Shcherbakov leg. ( AR); 1 ♀, same locality & collectors, 19 Aug. 1985 ( AR); 1 ♀, Khabarovsk Territory, Verkhnebureinskiy District, 20th km of Chegdomyn-Urgal road, mosses and plant debris on swampy sides of wayside lake with Carex spp., Poaceae gen. sp., Ledum palustre, Chamaedaphne calyculata, Vaccinium uliginosum, Spiraea sp., Sphagnum spp., undergrowth of Betula platyphylla and Larix gmelinii, 6 Oct. 2006, A.B. Ryvkin leg. ( AR); 1 ♂, Khabarovsk Territory, Verkhnebureinskiy District, Bureinskiy Nature Reserve (buffer zone) near ‘Strelka’ cordon, 550 m a.s.l., mosses, leaf litter and drift on banks of old channel of Umal’ta-Makit River: Sphagnum spp., Polytrichum sp., Carex spp., Poaceae gen. spp., etc., 30 Sep. 2006, A.B. Ryvkin leg. ( AR); 1 ♀, Khabarovsk Territory, Verkhnebureinskiy District, Bureinskiy Nature Reserve, ‘Strelka’ cordon, mari (bog), 28 Aug. 2006, A. Barševskis & U. Valainis leg. ( DUL); 3 ♂♂, 4 ♀♀, Khabarovsk Territory, Verkhnebureinskiy District, Bureinskiy Nature Reserve, Pravaya Bureya River basin near Medvezhye winter hut, 1050 m a.s.l., mosses and litter in slope sparse larch forest with Sphagnum spp., Rubus chamaemorus, Ledum palustre, Ptilium crista-castrensis, Pleurozium schreberi, Polytrichum spp., Carex? globularis, etc., 29 Jul. 2007, A.B. Ryvkin leg. ( AR); 1 ♂, same locality, 1100–1240 m a.s.l., mosses, lichens and litter near rill in upper part of slope and on bald mountain crest: Picea ajanensis, Pinus pumila, Rhododendron aureum, Duschekia sp., Larix gmelinii, Sphagnum spp., Ptilium crista-castrensis, Pleurozium schreberi, Hylocomium splendens, Rubus chamaemorus, Carex? globularis, etc., 29 Jul. 2007, A.B. Ryvkin leg. ( AR); 1 ♀, Khabarovsk Territory, Verkhnebureinskiy District, left side of Olga River valley 3 km up-stream of Sofiysk, 880 m, mosses, leaf litter & plant debris on gentle slope near rill amid mari with hummocks of Sphagnum spp., Carex? globularis, C. spp., Poaceae gen. spp., Ledum sp., Vaccinium uliginosum, V. vitis-idaea, Polytrichum sp., Hypnum sp., Hylocomium splendens, Pleurozium schreberi, Ptilium crista-castrensis, Betula spp., etc., 19 Aug. 2008, A.B. Ryvkin leg. ( AR); 1 ♂, Khabarovsk Territory, Verkhnebureinskiy District, Ust’- Urgal Nature Park (project), near Semicha River mouth, SE side of old channel, 280 m a.s.l., moss and plant debris in larch- Ledum sparse forest with Betula divaricata, Vaccinium uliginosum, Chamaedaphne calyculata, Sphagnum spp., Polytrichum spp., Dicranum spp., Cladonia spp., Eriophorum sp., Carex sp., etc., 29 Aug. 2009, A.B. Ryvkin leg. ( AR); 2 ♀♀, Khabarovsk Territory, Verkhnebureinskiy District, Dublikanskiy Nature Refuge, right side of Dublikan River valley, 1 km up-stream of cordon, NNW slope of bald mountain, 400 m a.s.l., mosses and litter on stones with pika burrows (permafrost!): Pleurozium schreberi, Hylocomium splendens, Ptilium crista-castrensis, Sphagnum spp., Ledum sp., Vaccinium vitis-idaea, Carex sp., Poaceae gen. sp., etc. among Larix gmelinii, Betula platyphylla, Alnus sp., Duschekia sp., undergrowth of Abies nephrolepis and Picea ajanensis, 27 Aug. 2008, A.B. Ryvkin leg. ( AR); 2 ♂♂, 1 ♀, same locality & biotope, 30 Aug. 2008, A.B. Ryvkin leg. ( AR); 1 ♂, Magadan Area, Ten’kinskiy District, near Sibit-Tyhellakh, peat-moss stripe, 28 May–07 Jun. 1982, D.I. Berman leg. ( AR); 2 ♂♂, 1 ♀, Magadan Area, Ten’kinskiy District, near Sibit-Tyhellakh, Jack London Lake, Sphagnum swamp on alluvial cone, 18 Aug. 1984, K.Yu. Eskov leg. ( AR); 1 ♀, Magadan Area, Ten’kinskiy District, near Sibit-Tyhellakh, ‘Aborigen’ field research station, alder shrubs near rill: in Sphagnum hillock, 24 Aug. 1984, K.Yu. Eskov leg. ( AR); 1 ♀, Magadan Area, Ten’kinskiy District, Detrin River basin, Vakkhanka Rill, northern swamp, soil traps, 30 May–9 Jun. 1981, S.P. Bukhkalo leg. ( AR); 1 ♂, same locality, swamp near landing place, soil traps, 7–17 Jun. 1982, S.P. Bukhkalo leg. ( AR); 1 ♂, same locality, swamp on glacial drift, 6–16 Jun. 1983, S.P. Bukhkalo leg. ( AR); 1 ♀, same locality, peat-moss stripe, 7–17 Jun. 1983, S.P. Bukhkalo leg. ( AR).
This species was originally described based on two males (HT: [ China:] Island in Sungari River; PT: [ Russia: S Maritime Province:] Kedrovaya Pad’ [Nature Reserve]); it was later cited for Hokkaido, Japan, and ‘Amur region [without more precise locality]’ ( Naomi & Puthz 1994). It should be noted that neither Herman (2001) nor Smetana (2004) mentioned the Chinese occurrence of this species in their respective catalogues. Both authors seem to have misinterpreted the terra typica as a Russian territory. Based on the new material above, S. raddei proves to be a very common species distributed widely in the Russian Far East.