Omalium constrictum, Shavrin, 2025

Omalium constrictum sp. nov.

( Figs 7 View FIGURES 4–7 , 12–15 View FIGURES 8–15 )

Type material. Holotype ♂ ( Fig. 7 View FIGURES 4–7 ; dissected): ‘ CHINA: C-Hubei, 2005 | Dahongshan, 30.4-1.5. | 31.5N 113.0E | leg. J. Turna’ <printed>, ‘ HOLOTYPE | Omalium | constrictum sp.n. | Shavrin A.V. des. 2025’ <red, printed> ( NMW). Paratype 1 ♀ (dissected): same data as the holotype, with an addition red printed label: ‘ PARATYPE | Omalium | constrictum sp.n. | Shavrin A.V. des. 2025’ ( NMW).

Description. Measurements (n=2): HW: 0.62–0.65; HL: 0.35–0.45; OL: 0.17–0.20; TL: 0.07; AL ( holotype): 1.21; PL: 0.50; PWmax: 0.75–0.77; PWmin: 0.63–0.65; ESL: 1.00–1.02; EW: 1.09–1.14; MTbL ( holotype): 0.47; MTrL ( holotype): 0.23 (MTrL 1–4: 0.08; MTrL 5: 0.15); AW: 1.02–1.16; AedL: 0.52; BL: 3.55 ( holotype)–3.68.

Habitus as in Fig. 7 View FIGURES 4–7 . Body, antennae and legs reddish; head darker, reddish-brown; mouthparts, tarsi, paratergites and apical part of abdomen yellowish. Punctation of head irregular, relatively fine and dense, denser in middle and deeper on infraorbital portions, each narrow portion in front of anteocellar foveae without punctures; neck with several fine punctures; punctation of pronotum about as that in middle of head, larger in middle, sparser in lateral, and finer and sparser in mediobasal portions; scutellum without punctures; punctation of elytra relatively sparse, larger and deeper than that in middle portion of pronotum, denser in mediobasal and sparser and finer in medioapical portions; abdominal tergites with indistinct, fine and relatively dense punctation. Body without microsculpture, except for scutellum and abdominal tergites which have fine isodiametric microreticulation. Anterior part of neck with several elongate erect setae; anterior and posterior margins of pronotum with row of short cuticular fringe.

Head 1.4–1.7 times as broad as long, with broad clypeus and convex distinctly explanate supra-antennal elevations, middle and infraorbital portions slightly elevated; posteriolateral margins of clypeus somewhat parallelsided, reaching about level of anterior third of eyes. Laterobasal parts of clypeus and infraorbital portions with elongate and narrow diagonal elevations between punctures; each postocular part of infraorbital portion with three elongate and narrow wrinkles. Anteocellar foveae wide and deep, not convergent latero-apicad, reaching level of anterior third of eyes. Temples distinctly more than twice shorter than longitudinal length of eyes, without distinct postocular ridges. Apical part of neck indistinctly narrowly impressed, with narrow longitudinal elevations between punctures. Distance between ocelli about 1.4 times as long as distance between ocellus and posterior margin of eye. Antenna with distinctly elongate antennomeres 6–8 and slightly transverse 9–10; antennomere 4 significantly shorter than 3, 5 distinctly longer and slightly broader than 4, 6 slightly longer and broader than 5, 7 slightly broader than 6, 8–9 slightly shorter and broader than 7, 10 slightly broader than 9.

Pronotum convex, 1.1 times as broad as long, 1.1–1.2 times as broad as head, from widest anterior third gradually narrowed posteriad toward obtuse posterior angles. Anterior angles widely rounded, not protruded anteriad.Anterior margin widely rounded. Lateral portions widely impressed, with wide and deep oval impression slightly below middle. Surface of disc with two long and very deep longitudial depressions, slightly broadened basad, and with moderately deep and narrow medioapical depression. Surface between all pronotal depression strongly and narrowly elevated, without elevations between punctures. Each lateroapical part with small rounded elevation.

Elytra broader than long, twice as long as pronotum, indistinctly broadened posteriad; lateral margins moderately widely impressed. Dorsolateral and apical portions of each elytron with strong subdiagonal elevations between punctures.

Metatarsi about twice as long as metatibia.

Abdomen about as broad as elytra, with intersegmental membranes between abdominal tergites III–VI, with two small oval wing-folding patches in middle of tegite IV.

Male. Posterior margin of abdominal tergite VIII truncate. Posterior margin of abdominal sternite VIII widely sinuate. Aedeagus with wide basal part, gradually narrowed toward long and narrow median lobe; median lobe concave laterally in preapical portion and slightly broadened in apical part, with rounded apex; mediolateral portions with short and moderately narrow accessory plates rounded apically; parameres wide, each from widest preapical part gradually narrowed apically toward somewhat rounded apex, with two moderately long apical and two preapical setae; internal sac long and moderately narrow, with two small, oval, sclerotized structures in basal portion ( Fig. 12 View FIGURES 8–15 ). Lateral aspect of aedeagus as in Fig. 13 View FIGURES 8–15 .

Female. Posterior margin of abdominal tergite VIII truncate. Posterior margin of abdominal sternite VIII slightly sinuate. Accessory sclerite short, with wide basal portion significantly narrowed apically ( Fig. 14 View FIGURES 8–15 ). Spermatheca as in Fig. 15 View FIGURES 8–15 .

Comparative notes. According to the general shape of the narrow median lobe, O. constrictum sp. nov. belongs to the Rivulare group ( Zanetti 1987, Shavrin 2023 a, 2025a). Based on the pronotum widest in apical third and the general shape of the median lobe, O. constrictum sp. nov. is similar to the Nepalese O. kumari Shavrin, 2023 , from which it can be distinguished by the larger and reddish body, longer antennomeres 7–10, larger and sparser punctation of the forebody, smaller and narrower apical part of the pronotum, narrower middle and broader apical portion of the median lobe, narrower parameres, different shapes of the female accessory sclerite and the spermatheca, and details of the morphology of the aedeagus.

Distribution. Omalium constrictum sp. nov. is known only from the type locality in Dahonghan Mts., China. The exact locality is unknown.

Etymology. The specific epithet is the Latin adjective constrictus, - a, - um (compressed). It alludes to the shape of the median lobe.

Bionomics. Bionomical data are unknown.