Omalium rougemonti, Shavrin, 2025

Shavrin, Alexey V., 2025, Review of the genus Omalium Gravenhorst, 1802 (Coleoptera: Staphylinidae: Omaliinae: Omaliini) of China, Zootaxa 5588 (4), pp. 501-543 : 533-536

publication ID	https://doi.org/10.11646/zootaxa.5588.4.1
publication LSID	lsid:zoobank.org:pub:444F5F59-9228-4100-9135-DF824FF9BACA
DOI	https://doi.org/10.5281/zenodo.14922588
persistent identifier	https://treatment.plazi.org/id/50613239-FFAE-6C63-FF0A-F996FE99FD91
treatment provided by	Plazi
scientific name	Omalium rougemonti
status	sp. nov.

Treatment

3.5.5. Omalium rougemonti sp. nov.

( Figs 27–28 View FIGURES 13–29 , 76, 79–81, 88)

Description. Measurements (n=12): HW: 0.58–0.62; HL: 0.35–0.42; OL: 0.17–0.20; TL: 0.05–0.06; AL (holotype): 1.20; PL: 0.45–0.52; PWmax: 0.67–0.71; PWmin: 0.63–0.67; ESL: 0.95–1.05; EW: 1.05–1.16; MTbL (holotype): 0.52; MTrL (holotype): 0.22 (MTrL 1–4: 0.09; MTrL 5: 0.13); AW: 1.00–1.06; AedL: 0.57–0.68; BL: 2.93–3.95 (holotype: 3.65).

Habitus as in Fig. 76 View FIGURES 76–78 . Body reddish-brown (pronotum of holotype and three paratypes and abdomen in some specimens distinctly paler); antennomeres 5–11 or 6–11 brown; mouthparts, antennomeres 1–4 or 1–5, lateral and basal portions of pronotum an paratergites of abdomen in some specimens yellowish; tarsi yellow. Punctation of head moderately dense and fine, sometimes denser in middle and coarser in basal half of infraorbital portions (two paratypes with denser, larger and coarser punctation in middle and on infraorbital parts); neck with fine and sparse or relatively large and dense punctation; punctation of pronotum slightly larger, deeper and sometimes coarser than that in middle part of head, finer and sparser in medioapical and mediobasal (some specimens) portions, and sparser in lateral parts; punctation of elytra about as that on pronotum, denser and coarser around scutellum and usually finer and sparser in middle portion; abdominal tergites with fine and sparse punctation. Anterior part of clypeus without or with traces of transverse microreticulation, laterobasal portions of clypeus with fine diagonal meshes in some specimens; neck without or with indistinct transverse microsculpture visible in mediobasal portion; scutellum with dense transverse or isodiametric sculpture; abdomen with dense isodiametric microsculpture. Anterior and posterior margins of pronotum with row of short cuticular fringe.

Head 1.4–1.6 times as broad as long, with strongly elevated lateral parts of clypeus and wide and deep anteriomedian depressions, reaching level of anterior third of eyes; posteriolateral margins of clypeus subparallel or slightly narrowed posteriad, reaching level of anterior third or middle of eyes. Latero-apical margin between anterior margin of eyes and clypeus with indistinct or distinct small semicircular notch. Dorsal surface without or with moderately strong longitudinal and diagonal wrinkles in laterobasal portions of clypeus, without or with transverse irregular elevations in middle, with longitudinal and diagomal elevations on infraorbital portions, usually stronger on postocular parts. Anteocellar foveae narrow and deep, slightly or strongly convergent latero-apicad toward level of middle length of eyes. Temples short, more than three times as long as longitudinal length of eyes, from posterior margins of eyes slightly narrowed posteriad toward widely rounded hind angles. Apical part of neck without or with narrow and deep depressions, with several narrow and short longitudinal elevations. Distance between ocelli 1.5– 1.8 times as long as distance between ocellus and posterior margin of eye. Apical maxillary palpomere slightly more than three times as long as penultimate segment. Antenna with distinctly elongate antennomeres 5–8 and slightly elongate 9–10; 4 slightly narrower and 1.3 times as long as 3, 5 distinctly longer than 4, 6 distinctly longer and slightly broader than 5, 7 slightly broader than 6, 8 slightly shorter than 7, 9–10 broader than 8, apical antennomere 1.2–1.3 times as long as preceding segment, from middle strongly narrowed toward acute apex.

Pronotum 1.3–1.4 times as broad as long, 1.1 times as broad as head, from widest anterior portion gradually narrowed posteriad.Apical angles widely rounded, not protruded anteriad.Anterior margin rounded, not or distinctly protruded anteriad. Laterobasal portions not concave in front of obtuse or subacute hind angles. Lateral portions deeply and moderately widely impressed, deeper in about middle and broader in laterobasal parts. Surface of disc with two wide and deep longitudinal depressions and deep, small, oval or rounded depression in medioapical portion; surface between all pronotal depressions distinctly elevated, sometimes stronger at sides of medioapical depression. Middle portion without or with irregular fine transverse and diagonal elevations between punctures.

Elytra twice as long as pronotum. Dorsal surface of each elytron with strong irregular elevations between punctures in mediobasal, mediolateral and apical portions (some specimens without elevations between punctures in middle parts of each elytron).

Abdomen slightly narrower than elytra, sometimes with narrow or wide intersegmental membranes between abdominal tergites III–V or III–VI.

Male. Posterior margin of abdominal tergite VIII truncate. Posterior margin of abdominal sternite VIII sinuate. Aedeagus with moderately wide basal portion, gradually narrowed toward median lobe; median lobe narrow and elongate, slightly sinuate in preapical portion, with small rounded apex; accessory plates narrow, short and distinctly convergent lateroapicad, rounded apically; parameres distinctly broadened in middle, and from middle slightly narrowed toward small rounded apices, reaching preapical portion of median lobe, each with one-two moderately long apical and one-two relatively short preapical setae; internal sac long and narrow, with two small oval structures in basal part ( Fig. 79 View FIGURES 79–87 ). Lateral aspect of the aedeagus as in Fig. 80 View FIGURES 79–87 ; apical portion of median lobe (lateral view) with distinctly broadened preapical portion, slightly curved ventrad, with somewhat rounded and disinctly crenulate ventrolateral margin ( Fig. 81 View FIGURES 79–87 ).

Female. Posterior margin of abdominal tergite VIII truncate. Posterior margin of abdominal sternite VIII truncate or rounded. Female accessory sclerite short, from widest basal portion gradually narrowed toward rounded apex ( Fig. 27 View FIGURES 13–29 ). Spermatheca as in Fig. 28 View FIGURES 13–29 .

Comparative notes. Based on the general shape of the body and the aedeagus, O. rougemonti sp. nov. is similar to the Himalayan O. secretum Cameron, 1924 , known from India and Nepal ( Shavrin 2023a). It can be distinguished from it by the shorter temples, more narrowed posteriad, the presence of small and deep depression in medioapical portion of the more convex pronotum, different shape of the median lobe, with shorter and broader apical portion of the median lobe, longer parameres with broader apical portions, broader apical part of the female accessory sclerite, and details of the morphology of the aedeagus.

Distribution. Omalium rougemonti sp. nov. is known from several localities in Emei Shan Mts. in Sichuan, Qin Ling Shan Mts. in Shaanxi, Daba Shan Mts. in Hubei and Tienmushan Mts. in Zhejiang, China ( Fig. 88 View FIGURE 88 ).

Etymology. Patronymic; the species is named in memory of Guillaume de Rougemont† (1945–2020), the collector of some type specimens.

Bionomics. Specimens were collected from 300 to 3055 m a.s.l. by sifting litter in mixed forests. One specimen in Emei Shan Mts. was collected by sifting in mixed forest with Abies and bamboo undergrowth, and one specimen from Daba Shan Mts. (C01-13C) was collected in mixed deciduous forest by sifting of moss, dead wood and mushrooms.

NMPC	Czech Republic, Prague, National Museum (Natural History)
CNC	Canada, Ontario, Ottawa, Canadian National Collection of Insects
OUMNH	United Kingdom, Oxford, University Museum of Natural History