Omalium japonicum Sharp, 1874

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 : 219-221

3.2.4.4. Omalium japonicum Sharp, 1874

( Figs 15 , 33 , 36–37 )

Omalium japonicum Sharp, 1874: 98 ; Watanabe 1990: 95; Kim & Ahn 2014: 153.

Omalium (Omalium) japonicum : Bernhauer & Schubert 1910: 54.

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. ’, ‘NHMUK015009856’ (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) .

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.

Figures

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 33–35. Habitus of Omalium: 33—O. japonicum (lectotype), 34—O. kurilicum (holotype), 35—O. niponense (holotype). Scale bar: 1.0 mm.

FIGURES 36–40. Aedeagus of Omalium (Figs 36–37—O. japonicum (Japan: Tsukuba Mt.), Figs 38–40—O. niponense (38— Japan: Futamata; 39–40—Russia: Maritime Province, Sikhote-Alin Nature Reserve)): 36, 38–39—aedeagus, parameral view, 37, 40—aedeagus, lateral view. Scale bar: 0.1 mm.