Omalium subsolanum Herman, 2001

Shavrin, Alexey V., 2025, Review of the genus Omalium Gravenhorst, 1802 (Coleoptera: Staphylinidae: Omaliinae: Omaliini) of Siberia and Far Eastern Russia, with notes on some species from Mongolia and Japan, Zootaxa 5646 (2), pp. 199-235 : 227-230

3.2.4.10. Omalium subsolanum Herman, 2001

( Figs 19 , 21 , 43 , 44–47 )

Omalium clavatum Luze, 1906: 522 .

Omalium subsolanum Herman, 2001b: 38 (replacement name for O. clavatum ).

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).

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.

Distribution. Omalium subsolanum is known from several localities in Siberia, Russian Far East (Amur Area) and Japan (Honshu) ( Fig. 21 ).

Bionomics. Detailed bionomical data are unknown.

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 (2001b) 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.

Figures

FIGURE 21. Distribution of Omalium in eastern Palaearctic region: O. golovatchi (triangles), O. subsolanum (circles).

FIGURES 10–19. Female accessory sclerite (Figs 10, 12, 14–19) and spermatheca (Figs 11, 13) of Omalium: 10–11—O. curtipenne, 12–13—O. diffine, 14—O. golovatchi, 15—O. japonicum, 16—O. kurilicum, 17—O. longicorne, 18—O. strigicolle, 19—O. subsolanum. Scale bar: 0.1 mm.

FIGURES 41–43. Habitus of Omalium: 41—O. scabrum (paratype), 42—O. strigicolle (Russia: Maritime Province, Sikhote- Alin Nature Reserve), 43—O. clavatum (lectotype). Scale bar: 1.0 mm.

FIGURES 44–49. Aedeagus of Omalium (Figs 44–47—O. subsolanum (Figs 44–45—Russia: Buryatia, valley of Irkut River; Figs 46–47—Japan:Ashiyasu-mura), Figs 48–49—O. strigicolle (Russia:AmurArea, Norskiy Reserve)): 44, 46, 48—aedeagus, parameral view, 45, 49—aedeagus, lateral view, 47—apical part of median lobe, lateral view. Scale bar: 0.1 mm.