Omalium anguliferum Shavrin, 2025, sp. nov.
Creators: name: Shavrin, Alexey V.
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Omalium
Omalium anguliferum

description: 3.2.1. Omalium anguliferum sp. nov.
(Figs 1, 4–6, 13, 30)
Type material examined. Holotype ♂: CHINA: SICHUAN: ‘ CHINA: SICHUAN PROV., | Emeishan Mt., 9.VI.2014, | LEIDONGPING env., 2410 m, | 29°32´40´´ 103°20´02´´E,’ <printed>, ‘ sift #8, mixed forest with Acer, | Abies, Picea, Rhododendron, | around limestone rocks, | J. Hájek & J. Růžička leg.’ <printed>, ‘HOLOTYPE | Omalium | anguliferum sp. nov. | Shavrin A.V. des. 2025’ <printed> (NMPC).
Paratypes (12 ♂♂, 11 ♀♀): CHINA: SICHUAN: 1 ♀: same data as the holotype (cSh); 2 ♂♂ (one specimen dissected): ‘ CHINA: SICHUAN PROV., | Emeishan Mt., 2420 m | JIEYINGDIAN TEMPLE, | 29°32´17´´ 103°19´59´´E,’ <printed>, ‘ 10.VI. 2014, sift #12, | secondary mixed forest | above temple, | J. Hájek & J. Růžička leg.’ <printed> (NMPC); 1 ♀ (dissected): ‘ CHINA: SICHUAN PROV., | Emeishan Mt., 2480 m | JIEYINGDIAN TEMPLE, | 29°32´01´´ 103°19´57´´E,’ <printed>, ‘ 7.VI. 2014, sift #6, | bamboo and mixed forest | below temple near road, | J. Hájek & J. Růžička leg.’ <printed> (NMPC); 1 ♂ (dissected), 1 ♀: ‘ CHINA: Sichuan | Emei Shan, Wannian | 1050 m, 19.–30.III.1999 | leg. P. JÄGER’ <printed> (SMNS); 3 ♂♂ (one specimen dissected), 3 ♀♀: ‘P.R. CHINA, Sichuan, | EmeiShan, N29°33´36.3´´ | E103°20´38.0´´, | 15.vi.2010, 1947m, | sifting33, V. Grebennikov’ <printed> (1 ♂, 1 ♀: cSh; 2 ♂♂, 2 ♀♀: CNC); 1 ♂, 3 ♀♀: ‘P.R. CHINA, Sichuan, | Emei Shan, N29°33.6´| E103°20.6´, 27.vi.–5.vii. | 2009, 1800–2400m, sifti-| ng11–17, V. Grebennikov’ <printed> (1♂, 1 ♀: cSh; 2 ♀♀: CNC); 2 ♂♂, 2 ♀♀: ‘P.R. CHINA. Sichuan, | EmeiShan, N29°33´36.3´´ | E103°20´38.0´´, | 22.vi.2010, 1947m, | sifting39, V. Grebennikov’ <printed> (1 ♂, 1 ♀: cSh; 1 ♂, 1 ♀: CNC); 1 ♂: ‘ CHINA: Sichuan (2) | Qingcheng-Shan, | Rückseite, 650–700m | 30.53.56N, 103.33.01E | 18.05.1997, M. Schülke’ <printed>, ‘ Omalium [handwritten] | spec. [handwritten] | det. M. Schülke 1999’ <printed>, ‘Museum für Naturkunde | Berlin | Sammlung M. Schülke’ <printed> (cSch); CHINA: SHAANXI: 2 ♂♂ (one specimen dissected): ‘CHINA: S-Shaanxi (Qinling Shan) | pass on rd. Zhouzhi — Foping, | 105 km SW Xi`an, N-slope, | 1990 m, 33°44´N, 107°59´E | leg. M. Schülke [C01-01]’ <printed>, ‘2./ 4. VII. 2001, | small creek valley, mixed | deciduous forest, bamboo, | small meadows, dead wood, | mushrooms (sifted) [C01- 01]’ <printed>, ‘Sammlung | M. Schülke | Berlin’ <printed> (cSch). All paratypes with additional red printed label: ‘ PARATYPE | Omalium | anguliferum sp. nov. | Shavrin A.V. des. 2025’.
Description. Measurements (n=24): HW: 0.51–0.57; HL: 0.34–0.41; OL: 0.12–0.17; TL: 0.07–0.10; AL (holotype): 1.00; PL: 0.44–0.52; PWmax: 0.61–0.72; PWmin: 0.59–0.65; ESL: 0.76–0.92; EW: 0.84–0.97; MTbL (holotype): 0.42; MTrL (holotype): 0.19 (MTrL 1–4: 0.07; MTrL 5: 0.12); AW: 0.84–0.90; AedL: 0.55–0.60; BL: 2.45–3.35 (holotype).
Habitus as in Fig. 1. Body brown to reddish-brown, with distinctly paler lateral and basal margins of pronotum and sometimes with slightly paler elytra and abdomen; antennomeres 5–11 or 6–11 brown; mouthparts, antennomeres 1–4 or 1–5 and legs yellow-brown; tarsi yellowish. Punctation of head dense, coarse and deep, sparser and finer in frontal and larger in middle portions, with interspaces between punctures in middle about as long as diameter of one nearest puncture or slightly shorter; neck with irregular, sparse and moderately fine punctation; punctation of pronotum regular, about as that in middle of head, distinctly finer and slightly sparser in mediobasal and significantly sparser in laterobasal portions; scutellum without punctures; punctation of elytra distinctly sparser, but larger and deeper than that on pronotum, coarser in medioapical part, finer and sparser along suture; abdominal tergites with fine and relatively dense punctation, indistinct on abdominal tergites VI–VIII. Forebody glossy; anterior portion of clypeus with fine transverse microreticulation, supra-antennal elevations with fine and sometimes indistinct diagonal meshes; lateral sides of neck with diagonal sculpture; pronotum and elytra without microsculpture; scutellum without or with indistinct fine transverse sculpture; abdomen with dense microsculpture, somewhat transverse on abdominal tergites IV–V and isodiametric on tergites VI–VIII. Anterior part of head with several moderately long and erect setae; lateral margins of pronotum with several short setae; abdominal tergites with sparse and short setation; posterior margin of pronotum with row of short cuticular fringe.
Head 1.3–1.5 times as broad as long, with broad clypeus and distinctly elevated supra-antennal elevations, with relatively narrow and deep anteriomedian depressions, almost reaching level of anterior margins or anterior third of eyes; posteriolateral margins of clypeus stretching posteriad toward level of anterior third of eyes. Latero-apical margin between anterior margin of eyes and clypeus without semicircular notch. Dorsal surface with strong longitudinal and diagonal elevations between punctures in middle and on infraorbital portions; irregular elevations on postocular portions sometimes forming three to four longitudinal wrinkles.Anteocellar foveae moderately narrow and deep, distinctly convergent latero-apicad toward level of middle or anterior third of eyes. Temples long, 1.7 times as long as longitudinal length of eye, from posterior margins of eyes slightly narrowed posteriad, each with subacute angle distinctly protruded basad; postocular ridges missing. Apical part of neck narrowly and moderately deeply depressed, with several short and narrow elevations; each lateral margin with acute small projections, slightly protruded laterad. Eyes large and convex. Ocelli large, located significantly behind level of posterior margins of eyes; distance between ocelli short, 1.6–1.8 times as long as distance between ocellus and posterior margin of eye. Maxillary palpi long, apical palpomere about four times as long as small and transverse penultimate segment, from widest basal portion gradually narrowed toward acute apex. Antenna reaching basal portion of elytra when reclined, with slightly elongate antennomeres 4–6 and distinctly transverse antennomeres 7–10; antennomere 3 slightly shorter and distinctly narrower than 2, 4 1.4 times as long as and narrower than 3, 5 distinctly longer than 4, 6 slightly longer and broader than 5, 7 slightly broader than 6, 8 distinctly broader than 7, 9–10 slightly broader than 8, apical antennomere 1.3–1.4 times as long as preceding segment, from middle gradually narrowed toward subacute apex.
Pronotum convex, 1.3 times as broad as long, 1.1–1.2 times as broad as head, from widest middle distinctly more narrowed posteriad than anteriad. Apical angles slightly protruded anteriad. Anterior margin widely rounded, slightly protruded anteriad. Laterobasal portions sometimes slightly concave in front of obtuse hind angles. Lateral portions relatively deeply and narrowly impressed, deeper in middle. Lateral margins narrowly marginated, sometimes indistinctly crenulate in latero-apical part.Surface of disc with two long and wide longitudinal depressions, broadened basad; some paratypes with indistinct oval depression in medioapical portion; each laterobasal portion widely and deeply depressed; surface between all pronotal depressions distinctly elevated. Middle portion with irregular longitudinal or diagonal elevations between punctures.
Elytra slightly broader than long, 1.7 times as long as pronotum, from basal portion slightly broadened posteriad; lateral margins marginated; lateral portions narrowly impressed; hind margins somewhat straight or widely rounded. Dorsal surface of each elytron with strong irregular elevations between punctures: transverse and subdiagonal in mediobasal and longitudinal in apical portions. Wings fully developed.
Metatarsi slightly more than twice shorter than metatibia.
Abdomen convex, about as wide as elytra, with two small oval wing-folding patches in middle of abdominal tergite IV and distinct narrow palisade fringe on apical margin of abdominal tergite VII, sometimes with narrow to wide intersegmental membranes between abdominal tergites III–V.
Male. Posterior margin of abdominal tergite VIII slightly and sternite VIII widely and moderately deeply sinuate. Aedeagus with wide basal portion, gradually narrowed toward median lobe; median lobe wide, with deeply sinuate lateral parts in preapical portion and widely rounded apex; mediolateral portions with narrow and relatively short accessory plates rounded apically; parameres moderately narrow, distinctly broadened apically, reaching preapical part of median lobe, each with four moderately long apical setae; internal sac wide and relatively short, with two small oval structures in basal part (Fig. 4). Lateral aspect of the aedeagus as in Fig. 5; apical portion of median lobe (lateral view) with three ventrolateral obtuse teeth (Fig. 6).
Female. Posterior margin of abdominal tergite VIII truncate. Posterior margin of abdominal sternite VIII truncate or rounded. Accessory sclerite with moderately narrow basal portion and relatively elongate median part, rounded apically (Fig. 9). Spermatheca not recognized.
Comparative notes. Based on the shape of temples, O. anguliferum sp. nov. belong to the acutangulum group, recently established for two species (O. acutangulum Shavrin, 2023 and O. amicorum Shavrin, 2023) from Nepal (Shavrin 2023a). Besides that, it related to Chinese O. rutilum sp. nov. and O. sectum sp. nov. Regarding the shape of postocular portions of head slightly narrowed posteriad and forming distinct hind angles, the shape of the pronotum with apical angles slightly protruded apicad, O. anguliferum sp. nov. is more similar to O. acutangulum and O. rutilum sp. nov. It can be distinguished from O. acutangulum by the finer elevations between punctures in basal part of the head, and slightly narrower pronotum with finer and smaller depressions on the pronotal disc. From O. rutilum sp. nov. it differ by the shape of transverse antennomere 8 and the shape of narrower pronotum, widest in middle and with less pronounced dorsal impressions. From both species it can be distinguished by the darker body, significantly denser and coarser punctation of the pronotum, different shape of the broader median lobe and other details of internal and external morphology of the aedeagus, and different shape of the female accessory sclerite. From O. sectum sp. nov. it differs by the widely rounded anterior angles of the pronotum and different morphology of the aedeagus.
Distribution. Omalium acutangulum sp. nov. is known from several localities in Qinling Shan mountain range in Shaanxi and in Emeishan and Qingcheng-Shan mountain ranges in Sichuan, China (Fig. 30).
Etymology. The specific epithet (Latin adjective: that carries angles) refers to the shape of temples strongly narrowed and protruding posteriad.
Bionomics. Specimens were collected at elevations from 650 to 2480 m a.s.l. and were sifted from litter of mixed coniferous (Acer, Abies, Picea, Rhododendron), and deciduous forest with bamboo, dead wood and mushrooms (C01-01).
description: Published as part of Shavrin, Alexey V., 2025, Review of the genus Omalium Gravenhorst, 1802 (Coleoptera: Staphylinidae: Omaliinae: Omaliini) of China, pp. 501-543 in Zootaxa 5588 (4) on pages 503-506, DOI: 10.11646/zootaxa.5588.4.1, http://zenodo.org/record/14896684