Stenus (Nestus) incautus Ryvkin, 2000

Ryvkin, Alexandr B., 2014, Stenus (Nestus) Pluvius Sp. N., With Notes On Some Related Species (Coleoptera: Staphylinidae: Steninae), Acta Biologica Universitatis Daugavpiliensis 14 (2), pp. 187-205 : 199

Stenus (Nestus) incautus Ryvkin, 2000

(Fig. 4)

incautus Ryvkin, 2000: 349

melanarius [pars]; Goreslavets & al., 2002: 348 (misidentification)

Material examined. RUSSIA: KRASNOYARSK TERRITORY: 1 male-HT, 1 female-PT( AR): Krasnoyarsk Territory, Severo-Yeniseyskiy District, Podkamennaya Tunguska River basin, Velmo River , 185 km upstream of river mouth, near trading post Velmo-I. River bank: Carex, Gramineae , shingles etc. 07/08/90. A.B.Ryvkin .— VOLGOGRAD AREA: 1 female ( AR): S of Krasnoslobodsk. 07.06.1995. K.A.Grebennikov leg. — 1 male ( AR): near Volgograd , S of Krasnoslobodsk. 10.04.1999. K.A.Grebennikov leg. — SAMARA AREA: 1 male ( AR): Kinel’skiy District, Krasnosamarskoye Forestry, flood-plain of Samara River , sand bank. 30.06.1993. I.N.Goreslavets leg. [‘ Stenus

sp-10 det. Goreslavetz I.N. ’].— 1 female ( AR): Samara, Kryazh, flood-plain of Samara River , in drift. 02.05.1992. I.N.Goreslavets leg. [‘ St. melanarius Steph. ’] .

Remarks. Until recently, the species has been known only from its Siberian type locality. But through the kindness of my colleagues Konstantin Grebennikov and Igor Goreslavets I have got an opportunity to study the material which confirms the presence of S. incautus in European Russia. Since Puthz (2010) recorded recently from Kiev, Ukraine a male of Central- European S. lohsei Puthz, 1965 closely related to S. incautus , both species are likely strict vicariants. S. incautus can be easily distinguished from S. lohsei by the body more flattened, by the puncturation smaller and more regular, and by the apical part of median lobe of the aedeagus evidently broader, with the constriction less sharp (see Figs. 4–5).