Omalium smetanai, 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 : 536-538

3.5.6. Omalium smetanai sp. nov.

( Figs 29 , 75, 82–84)

Type material examined. Holotype ♂ (dissected): CHINA: YUNNAN: ‘CHINA: N-Yunnan Zhong- | dian Co. pass 28km ESE Zhong- | dian, 27°43.9´N 99°58.2´E | 3700–3750m 22.VIII.2003 | A. Smetana [C131]’ <printed>, ‘HOLOTYPE | Omalium | smetanai sp. nov. | Shavrin A.V. des. 2025’ <red, printed> ( CNC).

Paratypes: YUNNAN: 4 ♀♀ (one specimen dissected; one specimen without right antennomeres 3–11 and abdomen): same data as the holotype, with additional red printed label: ‘PARATYPE | Omalium | smetanai sp. nov. | Shavrin A.V. des. 2025’. (2 ♀♀: cSh; 2 ♀: CNC).

Description. Measurements (n=5): HW: 0.46–0.49; HL: 0.34–0.36; OL: 0.13–0.15; TL: 0.06–0.07; AL (holotype): 0.80; PL: 0.38–0.40; PWmax: 0.58–0.60; PWmin: 0.52–0.54; ESL: 0.75–0.79; EW: 0.73–0.81; MTbL (holotype): 0.35; MTrL (holotype): 0.20 (MTrL 1–4: 0.03; MTrL 5: 0.12); AW: 0.75–0.84; AedL: 0.56–0.57; BL: 2.40–2.86 (holotype: 2.70).

Habitus as in Fig. 77 . Body dark-brown, with slightly paler elytra; antennomeres 6–11 brown; mouthparts, antennomeres 1–5 and legs yellow-brown. Punctation of head dense, moderately large and deep, distinctly denser in middle, denser and coarser on infraorbital portions; neck with fine sparse punctation; punctation of pronotum dense, slightly larger, coarser and deeper than that in middle part of head, with interspaces between punctures in mediolateral portion about as long as diameters of one-two nearest puncture, disinctly sparser in middle and mediobasal portions; punctation of elytra about as that on pronotum, denser, larger and coarser around scutellum and in mediolateral portions; abdominal tergites without or with fine and sparse punctation. Anterior part of head with transverse microsculpture, lateral portions of clypeus with irregular transverse and diagonal meshes; scutellum with fine isodiametric sculpture; abdominal tergites with dense isodiametric microreticulation.

Head 1.3 times as broad as long, with wide and moderately deep anteriomedian depressions, reaching anterior third of eyes; lateroposterior portions of clypeus distinctly narrowed basad toward level of anterior third or middle of eyes. Latero-apical margin between anterior margin of eyes and clypeus with small semicircular notch. Dorsal surface with fine diagonal elevations in laterobasal portions of clypeus, irregular, fine, transverse and longitudinal elevations in middle and in posterior half of infraorbital portions. Anteocellar fovea narrow, moderately deep, slightly convergent latero-apicad toward level of middle length of eyes. Temples twice as long as longitudinal length of eyes, from posterior margin of eyes gradually narrowed toward widely rounded hind angles. Apical part of neck not or indistinctly and narrowly depressed, with irregular short and narrow elevations. Distance between ocelli 1.3–1.5 times as long as distance between ocellus and posterior margin of eye. Apical maxillary palpomere about three times as long as penultimate segment. Antenna with slightly transverse antennomeres 8–10; 4 about as long as wide, twice shorter and indistinctly narrower than 3, 5 distinctly longer than 4, 6 slightly longer than 5, 7 slightly longer and indistinctly broader than 6, 8 slightly broader than 7, 9–10 distinctly broader than 8.

Pronotum 1.5 times as broad as long, 1.2 times as broad as head, from widest middle slightly more narrowed posteriad than anteriad. Apical angles widely rounded, indistinctly protruded anteriad. Anterior margin rounded, slightly concave in middle, not protruded anteriad. Laterobasal portions not concave in front of obtuse hind angles. Lateral portions deeply and moderately widely impressed, deeper slightly below middle. Middle portion without elevations between punctures.

Elytra about as long as broad, 1.9 times as long as pronotum; hind margins straight. Dorsal surface of each elytron with irregular diagonal elevations between punctures (holotype without elevations in median part along suture).

Abdomen slightly broader than elytra, with moderately wide intersegmental membranes between abdominal tergites III–IV (holotype and one paratype).

Male. Posterior margin of abdominal tergite VIII truncate. Posterior margin of abdominal sternite VIII widely sinuate. Aedeagus with wide basal portion, gradually narrowed toward median lobe; median lobe narrow and elongate, broadened in middle, slightly sinuate in lateral portions in front of middle, slightly broadened in posterior portion, with elongate small and rounded apex; accessory plates narrow and elongate, rounded apically; each paramere significantly broadened in middle and strongly narrowed toward small rounded apex, with one long and two short apical setae; internal sac long and narrow, with four small sclerotized structures in basal portion ( Fig. 82 ). Lateral aspect of the aedeagus as in Fig. 83 ; apical portion of median lobe (lateral view) hook-shaped, with crenulate ventrolateral margin, rounded hind tooth and small rounded apex ( Fig. 84 ).

Female. Posterior margin of abdominal tergite VIII truncate. Posterior margin of abdominal sternite VIII widely rounded. Accessory sclerite from widest basal portion strongly narrowed toward significantly elongate narrow median part with subacute apex ( Fig. 29 ). Spermatheca not recognized.

Comparative notes. Based on the general shapes of the body and the aedeagus, O. smetanai sp. nov. is similar to O. lama sp. nov. (see above), from which it can be distinguished by distinctly more elongate antennomeres 6–10, the longer temples, sparser punctation of the head, slightly narrower elytra, slightly broader apical half of the median lobe distinctly concave in preapical portion, the presence of distinct dorsolateral hook in apical part of the median lobe (lateral view), slightly shorter parameres, narrower apical part of the female accessory sclerite, and other details of the external and internal morphology of the aedeagus.

Distribution. Omalium smetanai sp. nov. is known only from the type locality in Zhongdian, northern Yunnan, China ( Fig. 75 ).

Etymology. Patronymic; the species is named in the memory of Aleš Smetana† (1931–2021), the collector of type specimens.

Bionomics. Specimens were collected from altitudes 3700 to 3750 m a.s.l. Specimens were collected by sifting of leaf litter, rotting wood, moss and various floor debris, particularly around and under mushrooms in various stages of development in an degraded original Abies , Sorbus , Larix , Rhododendron forest with various deciduous shrubbery undergrowth [C131].

Figures

FIGURE 75. Distribution of Omalium in China: Omalium lama (rounds), O. pseudojaponicum (square), O. smetanai (triangle)

FIGURES 13–29. Female accessory sclerite (Figs 13–14, 16, 18, 20–22, 24, 26, 28, 30) and spermatheca (Figs 15, 17, 19, 23, 25, 27, 29) of Omalium: 13—O. anguliferum, 14–15—O. rutilum, 16–17—O. cocleare, 18–19—O. contiger, 20—O. kurbatovi, 21—O. schuelkei, 22–23—O. bambusaphilum, 24–25—O. confertum, 26—O. lama, 27–28—O. rougemonti, 29—O. smetanai. Scale bar: 0.1 mm.

FIGURES 76–78. Habitus of Omalium: 76—O. rougemonti (holotype), 77—O. smetanai (paratype), 78—O. tibetanum (holotype). Scale bar: 1.0 mm.

FIGURES 79–87. Aedeagus of Omalium (Figs 79–81—O. rougemonti (paratype), Figs 82–84—O. smetanai (paratype), 85– 87—O. tibetanum (holotype)): 79, 82, 85—aedeagus, parameral view, 80, 83, 86—aedeagus, lateral view, 81, 84, 87—median lobe, lateral view. Scale bar: 0.1 mm.