Leptogenys leleji

Identification
This species is well distinguished from the other Vietnamese and Oriental congeners with a set of the following characters in the worker: cephalic capsule wider than long; anterior clypeal margin fringed with narrow translucent lamella; mandibles linear, a large gap formed between clypeus and mandible when fully closed; basal flagellar (third antennal) segment elongate; dorsum of body with standing hairs; propodeum with lateral teeth, posterior apex of petiole in profile drawn out into a tooth.

Distribution based on Regional Taxon Lists
Oriental Region: Vietnam.

Nomenclature

 *  leleji. Leptogenys leleji Zryanin, 2016: 51, figs 1–5 (w.q.) VIETNAM.

Description
Worker, holotype. Measurements and indices: HL 2.18, LCM 1.45, HW 2.13, ML 1.88, EL 0.40, SL 2.10, PW 1.41, WL 3.70, PNH 1.08, PNL 1.34, PNW 0.83; CI 98, SI 99, LNI 81, DNI 62 Habitus of worker as in Fig. 1. Head in full-face view markedly wider anteriorly than posteriorly, lateral and posterior margins forming continuous convexity, occipital carina distinct. Clypeus triangularly produced, with a blunt apex; anterior clypeal margin fringed with narrow translucent lamella, without peg-like setae medially; median longitudinal carina of clypeus sharp. Eyes large, weakly convex, placed dorsolaterally on head, their greatest diameter greater than maximal width of scape. Frontal groove shallow, extending to the level of posterior margin of eye. Mandibles long, feebly curved near bases, with only apical tooth and distinct crest along basal margin; blades in full-face view generally same width from the base to apex; a large gap formed between clypeus and mandible when fully closed (Fig. 2); basal groove indistinct. Palp formula: maxillary 4, labial 4. Antennal scape relatively short (SI 99). Basal flagellar (third antennal) segment elongate, markedly longer than neighboring antennal segments (the lengths of the segments 2–4: 0.35 mm, 0.53 mm, 0.38 mm). Mesosoma (alitrunk) with deep and wide, transversally striate metanotal groove that divides dorsal outline of mesosoma into two distinct convexities in lateral view. Mesonotum wider than long, with markedly median impression on posterior half (Fig. 3); anteroventral mesopleural carina well-developed, forming small angular lobe anteriorly; epicnemial carina projected anteriorly into distinct laminate and angulate epicnemial process; anapleural sulcus divides mesopleuron into smaller anepisternum and larger katepisternum; mesometapleural suture well impressed. Metapleural-propodeal suture developed as ridge that extends from propodeal spiracle and broadened toward metathoracic spiracle; propodeal spiracle slit-like; bulla of metathoracic spiracle convex. Propodeum armed with triangular tooth at the level of spiracle; propodeal declivity with carina uniting apices of these teeth; area anteriad to the carina concave in cross-section, with mostly smooth and shining surface; area posteriad to the carina depressed as a broad transverse sulcus. Apex of protibia without setae; first protarsal segment with comb of stout setae opposite strigil; meso- and metatibial apex each with two apical spurs and several setae; posterior metacoxal swelling well developed; tarsal claws pectinate. Petiole with convex anterior margin, and straight ascending dorsal margin in lateral view; both margins joined by convexity; dorsal margin ends in blunt pointed tooth that projects beyond posterior margin by almost one-fifth node length, tooth forms approximately 30-degree angle with longitudinal axis. Posterior margin of petiole in lateral view straight but not sinuate; posterior face flat and sharply margined laterally. Node longer than wide in dorsal view, its anterior margin little more than half of posterior margin (Fig. 3); cross-section of petiolar node at mid-length with convex sides. Subpetiolar process shaped as sub-rectangular tubercle with gentle posterior slope. Anterior and dorsal margins of first gastral (third abdominal) segment joined through a continuous convexity; constriction between first and second gastral segments well marked. Prora shaped as sharp, ventrally directed lobe at anteroventral angle of first gastral segment. Pygidium with indistinct median carina, hypopygium with a row of small setae close to base of sting. Cephalic dorsum between and behind eyes mostly smooth and shinning, with shallow piligerous punctae; malar space and frontal area striate; clypeus with fine longitudinal to oblique striae, which are more pronounced antero-medially. Antennae covered with dense piligerous punctulae. Dorsal surface of mandible with fine striation. Propleuron and pronotal dorsum sulcate; mesopleuron mostly smooth and shining, katepisternum scrobiculate along mesometapleural suture; metapleuron sulcate to scrobiculate; dorsum of propodeum with irregular fovea and median sulcus; metanotal groove with cross-ribs. Petiole scrobiculate, with rimose posterior face. Gaster smooth and shining. Body with abundant suberect to erect hairs; apressed pubescence present on cephalic dorsum, antennae and legs. Longest hairs present on median lobe of clypeus. Body colour mostly black to dark brown, with blue reflection of smooth surfaces. Antennae, mandibles, and legs mostly brown. Gastral apex and edges of last sclerites, base and apex of scape, crest on basal margin of mandible, last segments of tarsus dull yellow.

Etymology. The species is named in honor of the head of the Laboratory of Entomology (Institute of Biology and Soil Science, Vladivostok, Russia), Prof. Arkadiy S. Lelej, the authority of fauna and taxonomy of Hymenoptera