Omalium scapulare Coiffait, 1982

Shavrin, Alexey V., 2023, A revision of the genus Omalium Gravenhorst, 1802 (Coleoptera: Staphylinidae: Omaliinae) of the Himalayan region, Zootaxa 5369 (2), pp. 151-206 : 183-186

3.2.4.2.5. Omalium scapulare Coiffait, 1982

( Figs 18 , 57 , 62–65 )

Omalium scapularis Coiffait, 1982: 152

Omalium scapulare : Herman 2001: 532, Schülke & Smetana 2015: 348

Type material. Holotype of Omalium scapularis Coiffait, 1982 ♁ (aedeagus was glued on the same plate with the specimen): ‘NEPAL-Expedition | Jochen Martens’ <printed>, ‘südl. Dhaulagiri | Dhorpatan | 3000–3200 m | V. 197[printed]3 [handwritten]’, ‘6.’ <printed>, ‘TYPE’ <red, printed>, ‘ Holo- [handwritten] | TYPUS’ <red label with black margins, printed; other side of the label: ‘SMF | C. 15034’ [handwritten]>, ‘ Omalium | scapulare | H. COIFFAIT det. 19[printed]79’ <handwritten in black Indian ink>, ‘ Omalium | scapularis Coiff. ’ <handwritten in blue pen>, ‘SNG-Museum | Frankfurt/Main | Loan-000299’ <printed>, ‘ Omalium | scapulare Coiffait, 1982 | Shavrin A.V. det. 2023’ <printed> (SF).

Material examined. INDIA: UTTARAKHAND: 4 ♁♁, 5 ♀♀: Garhwal, au-dessus Pauri. 1900 m a.s.l. 28.10.1979. I. Löbl leg. (cSh, MHNG) ; WEST BENGAL: 1 ♁: Darjeeling District, Tonglu. 3100 m a.s.l., sifted litter under bushes in a pasture. 16.10.1978. C. Besuchet & I. Löbl leg. (MHNG) ; NEPAL: GANDAKI: 1 ♀: Manaslu Mts., Dudh Pokhari Lekh, upper Dordi Khola Valley. 2600– 2300 m a.s.l., sifting. 15– 17.04.2003. J. Schmidt leg. (NME) ; BAGMATI: 5 ♁♁, 6 ♀♀: Yardang Ridge NE Barahbise. 3250 m a.s.l., sifted forest floor litter in a fir and Rhododendron forest. 05.05.1981. I. Löbl & A. Smetana leg. (cSh, MHNG) ; 1 ♁: Mere Dara. 3100–3300 m a.s.l., under stones in a dry creek. 07.04.1981. I. Löbl & A. Smetana leg. (MHNG) ; 3 ♁♁, 3 ♀♀: same data, near Mere Dara. 3000 m a.s.l., Rhododendron forest, at the pass, leaf litter and moss on trees and on the floor. 07.04.1981 (cSh, MHNG) ; 1 ♁: same data, Pokhare NE Barahbise. 2800 m a.s.l., sifted leaf litter and moss in a oak forest. 02.05.1981 (MHNG) ; 2 ♀♀: same data, above Shermathang. 2900 m a.s.l., sifted leaf litter and fern in a mixed Rhododenron and oak forest. 26.04.1981 (MHNG) ; 1 ♁, 1 ♀: same data, Gul Bhanjyang. 2600 m a.s.l., old oak forest on a steep slope, sifted debris around trees. 06.04.1981 (MHNG) ; 1 ♁, 2 ♀♀: same data, Burlang Bhanjyang. 2600 m a.s.l., sifted moss and leaf litter near a source. 05.04.1981 (MHNG) ; 1 ♁: Dolakha District, SW Kalinchok Mt. 3100 m a.s.l., sifted in mixed forest with Rhododendron , Abies spectabilis and Berberis . 19– 23.04.1995. J. Martens & W. Schawaller leg. (SMNS) ; 1 ♀: Latipur District, Phulchoki Mt. 1800–2000 m a.s.l., sifted in degraded extremely dry forest with Quercus semecarpifolia . 25.04.1995. J. Martens & W. Schawaller leg. (SMNS) ; KATHMANDU: 14 ♁♁, 12 ♀♀: Phulcoki. 2500 m a.s.l., sifted rotten wood and branches along a fallen oak tree. 30.04.1984. I. Löbl & A. Smetana leg. (cSh, MHNG) ; 1 ♀: same data. 2400–2600 m a.s.l., under stones. 28– 30.04.1984 (MHNG) ; 1 ♀: same data. 2550 m a.s.l., sifted rotten oak branches and wood infected by fungi. 29.04.1984 (MHNG) ; KoSHI: 1 ♀: Goru Dzure Dara. 3350 m a.s.l., sifted moss, fern and grass. 09.04.1984. I. Löbl & A. Smetana leg. (MHNG) .

Redescription. Measurements (n=68): HW: 0.42–0.57; HL: 0.35–0.45; OL: 0.12–0.15; TL: 0.08–0.10; AL: 0.87–1.03; PL: 0.37–0.45; PWmax: 0.57–0.69; PWmin: 0.55–0.62; ESL: 0.75–0.92; EW: 0.74–0.95; MTbL (averaged): 0.45; MTrL (averaged): 0.25 (MTrL 1–4: 0.10; MTrL 5: 0.15); AW: 0.70–0.97; AedL: 0.38–0.70; BL: 2.19–3.65 (holotype: 2.50).

Habitus as in Fig. 57 . Head, pronotum and elytra reddish-brown to dark brown, usually with darker head and abdomen (body of some specimens dark brown); lateral and basal portions of pronotum, elytra and abdomen yellow-brown to brownish; antennomeres 6–11 brown; mouthparts, antennomeres 1–5, legs and paratergites yellowish to yellow-brown (some specimens with darker paratergites). Punctation of head dense, finer in apical and denser, slightly larger and deeper in middle portions, punctation of infraorbital portions sometimes slightly coarser between anteocellar foveae; punctation of nuchal constriction moderately dense, fine or large; punctation of pronotum very dense, large and deep, with interspaces between punctures in middle about as long as diameter of one-two nearest punctures, sparser and finer in mediobasal portion (some specimens with moderately sparse and fine punctation in middle); punctation of elytra about as that on pronotum, usually sparser and sometimes finer along suture. Head without meshes except of anterior portion of clypeus with distinct transverse microreticulation and nuchal constriction with fine isodiametric sculpture; pronotum withut sculpture, but some specimens with traces of very fine transverse microsculpture in medioapical portion; scutellum with fine isodiametric meshes or without them; elytra without microsculpture.

Head 1.2 times as broad as long, with wide clypeus and distinctly convex and moderately wide supra-antennal elevations, with long and deep anteriomedian depressions. Dorsal surface without or with distinct elevations between punctures in middle, infraorbital portions usually with strong longitudinal elevations between punctures (these elevations in some specimens forming several irregular, elongate and narrow wrinkles); each lateral portion between clypeus and eyes with two to three long and narrow elongate wrinkles stretching posteriad toward nuchal constriction. Anteocellar foveae deep and long, sublinear or slightly divergent anteriad toward level of middle or anterior third of eyes. Temples 1.5 times as long as longitudinal length of eyes, moderately wide and convex, without distinct postocular ridges. Distance between ocelli about 1.5 times to twice as long as distance between ocellus and posterior margin of eye. Antenna with slightly transverse antennomeres 8–10; antennomere 4 distinctly shorter and narrower than 3, slightly longer than broad, 5 slightly longer and broader than 4, 6 slightly longer and broader than 5, 7 slightly shorter and broader than 6, 8 slightly shorter and distinctly broader than 7, 9–10 distinctly broader than 8, apical antennomere 1.4–1.8 times as long as 10, from about middle gradually narrowed toward rounded or acute apex.

Pronotum 1.2–1.3 times as broad as head, from apical third gradually narrowed posteriad, with apical angles slightly protruded anteriad. Dorsal surface of disc with two distinct wide longitudinal depressions, sometimes with small oval depression in medioapical portion. Median surface of disc with longitudinal elevations between punctures or without them.

Elytra distinctly broader than long, about twice as long as pronotum, from middle slightly broadened posteriad. Surface of each elytron in apical and median portions with diagonal and longitudinal elevations between punctures.

Abdomen slightly narrower or broader than elytra.

Male. Antennomeres 8–10 slightly transverse. Posterior margin of abdominal tergite VIII straight or rounded. Posterior margin of abdominal sternite VIII widely concave. Aedeagus with wide basal portion, slightly narrowed toward middle, with long and wide median lobe, widely rounded apically; mediolateral portions with small, narrow and moderately short sclerotized accessory plates rounded apically; parameres moderately narrow, significantly shorter than apex of median lobe, distinctly widened in apical portions, with three long apical setae; internal sac moderately long and narrow, with U-shaped elongate sclerotized structure in basal portion ( Fig. 62 ). Lateral aspect of the aedeagus as in Fig. 63 ; apical portion relatively narrow, curved, with slightly crenulate inner margin ( Fig. 64 ).

Female.Antennomeres 8–10 less transverse. Posterior margins of abdominal tergite VIII and sternite VIII stright or slightly rounded. Accessory sclerite with wide basal portion and elongate moderately wide median part, gradually narrowing apicad ( Fig. 18 ). Spermatheca not recognized.

Comparative notes. Regarding the shape of the pronotum widest in apical third, O. scapulare is similar to O. altivagans from Kashmir, from which it can be distinguished by the paler elytra, the presence of distinct longitudinal elevations on infraorbital portions of head, narrower median lobe and parameres, and other external and internal details of the aedeagus (see the key above).

Distribution. Omalium scapulare is distributed from Uttarakhand to western part of Nepal and West Bengalia ( Fig. 65 ).

Bionomics. Specimens were collected at elevations from 1900 to 3350 m a.s.l. Specimens were taken mainly by sifting leaf litter, mosses and rotten wood in forests with Rhododendron , Abies , Quercus , etc.

Remarks. Omalium scapulare was originally descibed based on three specimens from “ Népal, südl. Dhaulagiri, Dhorpatan, 3000–3200 m ...”. It is here recorded from India (Uttarakhand and West Bengal) for the first time.

Figures

FIGURE 65. Distribution of Omalium scapulare in the Himalayan region.

FIGURES 8–18. Female accessory sclerite (Figs 8, 10–16, 18) and spermatheca (Figs 9, 17) of Omalium: 8–9—O. acutangulum, 10—O. amicorum, 11—O. amplissimum, 12—O. bilobum, 13—O. alticola, 14—O.beesoni, 15—O. altivagans, 16–17—O. marginatum, 18—O. scapulare. Scale bar: 0.1 mm.

FIGURES 56–58. Habitus of Omalium: 56—O. marginatum (holotype), 57—O. scapulare (Nepal, Bagmati), 58—O. angustissimum (holotype). Scale bars: 1.0 mm.

FIGURES 62–64. Aedeagus of Omalium scapulare (Nepal: Bagmati): 62—aedeagus, parameral view, 63—aedeagus, lateral view, 64—median lobe, lateral view. Scale bar: 0.1 mm.