Nebria (Pseudonebriola) tsambagarav, Huber & Schnitter, 2020

Huber, Charles & Schnitter, Peer Hajo, 2020, Nebria (Pseudonebriola) tsambagarav sp. nov., a new alpine species from the Mongolian Altai (Coleoptera, Carabidae), Alpine Entomology 4, pp. 29-38 : 29

Nebria (Pseudonebriola) tsambagarav sp. nov. Figs 3 , 5 , 6 , 7 , 8

Type material.

Holotype ♂: 48°41 ’27.1” N, 90°40 ’33.4” E; Mongolei, Bajan Ulgij Aimak, Tsambagarav uul; alpine Zone: Bachufer; 3168 üNN; 1. 7. 2016; 20 MG 2016 [internal abbreviation of the collector: location No. 20, Mongolia expedition 2016]; leg. Schnitter ( NMBE).

Paratypes: 31 ♂, 22 ♀, same data as holotype ( NMBE, ZIN, cBK, cSCHN).

Description.

Body size: 7.5-9 mm.

Colour: Dorsal surface black, head black, without lightened spots on the vertex; appendages of the head brownish lightened, always lighter than the head. Antennal scape black, antennomeres 2-11 brown with darkened apices. Femora black, tibiae and tarsomeres brown, apices of tarsomeres usually black.

Head: Mandibles short; stipes flat, smooth, with 4-6 setae. Anterior margin of the labrum straight, bearing six setae. Anterior margin of the clypeus straight or slightly concave; clypeus laterally unisetose. Frontoclypeal suture concave. Frons with transverse wrinkles, which roundly merge into the lateral and longitudinal supraorbital wrinkles. Eyes protruding, temples present, oblique. Head supraorbitally unisetose. Disc impunctate with an isodiametric microreticulation. Antennae long and thin, extending to the end of the basal third of the elytra. Antennal scape as long as the eye’s diameter (ratio antennal scape length/eye length = 0.98 ± 0.03 (0.93-1.04), slightly conical to suboval, distinctly narrowed basally and slightly apically, with one dorsoapical seta (Fig. 4 ). Ratio antennal scape length/scape width = 2.16 ± 0.07 (2.05-2.26). 2nd antennomere with one long ventroapical and one long dorsoapical seta, and generally (in 89% of the examined specimens) with 1-2 additional, often hardly visible short setae on the apex; therefore the 2nd antennomere trisetose (in 47%) or even quadrisetose (in 42%) (Fig. 5 ). Ligula short, triangular, broad at base, with two apical setae. Penultimate labial palpomere trisetose. Mentum bidentate, medially hardly incised. Median teeth with one seta at each side. Lobus lateralis of the mentum wide, apically faintly rounded or even rectilinearly narrowed, spina apicalis short, triangular, incisio lateralis distinct. Submentum bilaterally with 3-4 setae.

Pronotum (Fig. 6 ): Cordate, widest at apical third or even forth; ratio maximum width/length = 1.43 ± 0.03 (1.39-1.49). Anterior angles widely rounded, faintly protruding. Lateral margin evenly rounded to the anterior angles, faintly rounded to the posterior angles with a distinct sinuation in front of the posterior angle. Lateral margin of the posterior angles long. Posterior angles rectangular or even acutely turned outwards. Ratio apical pronotal width/maximum pronotal width = 0.80 ± 0.02 (0.78-0.84). Apical margination of the pronotum restricted to lateral one-third. Basal margin straight, occasionally laterally faintly curved, the posterior angles not protruding backwards. Basal width of the pronotum 0.92 (0.88-0.97) times the anterior width. Lateral groove distinct, narrow, flat, impunctate or with isolated dents, laterally narrowly edged, slightly broadened to the anterior angle, posteriorly joining the deep basal fovea. One midlateral seta present near widest point of the pronotum; occasionally bilateral-bisetose (2%) or asymmetrically uni-/bisetose (2%). Basolateral seta present. Apical and basal transverse impression coarsely but sparsely punctate. Median longitudinal impression distinct, reaching the posterior border of the pronotum. Disc with isodiametric microreticulation. Prosternal process wide, triangular, laterally slightly margined, medially flat, apically bulging and immarginate. Proepisternum smooth and impunctate.

Elytra: Silhouette suboval, apically faintly expanded, maximum width at two thirds. Ratio length/width of the elytra = 1.53 ± 0.02 (1.51-1.57). Elytral width = 1.59 ± 0.04 (1.51-1.66) times the pronotal width. Lateral margin faintly rounded, apex acutely rounded. Basal margination slightly curved, joined at an obtuse angle with the lateral margination. Shoulder flatly curved. Hindwings vestigial. Humeral and apical carinae little pronounced. Striae 1-7 distinct, punctate, stria 8 as a row of punctures. Striae 1-3 reaching the apex, the other striae obliterate slightly in front of the apex. Intervals on disc flat, interval 3 generally asetose (76%) on disc, disregarding the always present apical seta, occasionally with one seta on the disc (24%). Scutellar seta absent. Microsculpture isodiametric.

Ventral surface: Mes- and Metepisterna smooth and impunctate. Metacoxa basally and apically unisetose. Sternum II laterally faintly and widely dispersed punctate. Sternum III medially asetose. Sterna IV-VI each with one posterior paramedial seta. Anal sternum paralaterally unisetose in the male, bisetose in the female.

Legs: All tarsomeres dorsally glabrous; metatarsomere 4 ventrally with a short projecting tooth. Metafemur dorsoapically with a few short setae.

Male genitalia: Edeagus (Fig. 7C ): Base of the median lobe small; the base decreasing abruptly to the thin mid-shaft. Mid-shaft strongly curved at base on inner side, moderately curved to the apex. Apex straight, faintly deflected to the left, in front of the long tip ventrally faintly convex. Mid-shaft of the endophallus with short setae.

Female genitalia: Gonocoxa (Fig. 8A ): Gonocoxite 2 slender, dagger-like, curved, two fifth the length of gonocoxite 1, broad at base, distinctly narrowing near base, narrowing towards apex which is faintly deflected. Apex rounded, hardly arcuate and grooved dorsally. Ventral preapical insertion furrow short-oval, with two nematiform setae. Gonocoxites ventrally unjointed and continuously sclerotized, dorsally separated by a membranous area.

Habitat

(Figs 9 , 10 ). The new species was found in the alpine region of the Tsambagarav uul exclusively under bigger stones along the riverbanks of small rivulets. The water ran off higher snowfields. Directly at the snow fields not any specimen was found.

Ecology.

Hydrophilic, ripicol, cold-preferring, alpine level.

Etymology.

The specific epithet refers to the type locality, the Tsambagarav uul; noun in apposition.

Distribution

(Fig. 11 ). N. tsambagarav sp. nov. is known only from the type locality at an altitude of 3168 m a.s.l. at the Tsambagarav uul, a mountain (with the summit at 4165 m a.s.l.) of the Mongolian Altai in the westernmost province of Bayan Ölgii of Mongolia.

The Mongolian Pseudonebriola species are restricted to the main ridge of the Mongolian Altai ( N. medvedevi ), to the Tsambagarav mountain, the easternmost ridge bordering the Great Lakes Depression ( N. tsambagarav sp. nov.), and to the Northwestern part of the Gobi Altai ( N. kerzhneri ).

Figures

Figure 3. Nebria (Pseudonebriola) tsambagarav sp. nov., habitus, holotype. Scale bar: 5 mm.

Figure 4. Antennal scape: A, Nebria (Pseudonebriola) tsambagarav sp. nov. paratype; B, N. (P.) medvedevi Shilenkov, 1982, paratype. Scale bar: 0.5 mm.

Figure 5. Second antennomere of right antenna of Nebria (Pseudonebriola) tsambagarav sp. nov., paratype, with four apical setae. Scale bar: 0.1 mm.

Figure 6. Pronotum: A, Nebria (Pseudonebriola) kerzhneri Shilenkov, 1982, holotype; B, N. (P.) medvedevi Shilenkov, 1982, paratype; C, N. (P.) tsambagarav sp. nov., paratype. Scale bar: 1 mm.

Figure 7. Median lobes; A-B dried lobes, C-D embedded lobes, A-C with partially everted endophallus: A, Nebria (Pseudonebriola) kerzhneri Shilenkov, 1982, holotype; B, N. (P.) medvedevi Shilenkov, 1982, paratype; C, N. (P.) tsambagarav sp. nov., holotype; D, N. (P.) kaszabi Shilenkov, 1982, Urunkhaika, Marakol Lake, Kazakhstan. Scale bar: 1 mm.

Figure 8. Right gonocoxa (in ventral view): A, Nebria (Pseudonebriola) tsambagarav sp. nov., paratype; B, N. (P.) kaszabi Shilenkov, 1982; Urunkhaika, Marakol Lake KAZ. Scale bar: 0.5 mm.

Figure 9. Tsambagarav uul, Bajan Oelgii province, Western Mongolia. Photo: Peer Schnitter.

Figure 10. Habitat of Nebria (Pseudonebriola) tsambagarav sp. nov. on Tsambagarav uul; rivulet at 3168 m a. s. l. Photo: Peer Schnitter.

Figure 11. Map of the Altai Mountain range displaying the distribution of Pseudonebriola species.