Psen fronistriatus Deng, Ma & Li, 2025, sp. nov.

Psen fronistriatus sp. nov. Figs 1 A – J, 2 A-L Type material. Holotype. China • ♀; Inner Mongolia, Helan Mountain; 38°57'45"N, 105°51'8"E; 24. VII. 2006; 1833 m elev.; collected by Ming LUO. Paratypes: China • 1 ♂; same data as holotype; China • 1 ♀; Yunnan Province, Gaoligong Mountain, Dulong River Tunnel; 27°50'56"N, 98°28'3"E; 15. VII – 2. VIII. 2020; 2824 m elev.; collected by Lang YI; China • 1 ♂; Shaanxi Province, Yan’an City, Ganquan County, Liulimao; 36°10'3"N, 109°21'26"E; 5. VII. 1971; 1077 m elev.; collected by Jikun Yang. All types deposited in YNAU. Diagnosis. The new species is similar to Psen seminitidus van Lith, 1965, but differs from it and other congeners by the following characteristics (characters of P. seminitidus in parentheses): 1) the posterior surface of the propodeum lacks an oblique longitudinal ridge (the posterior surface of the propodeum has weakly oblique longitudinal carinae); 2) flagellomeres VII – X have linear tyloids beneath in the male (flagellomeres V – VI or V – VII beneath have linear tyloids); 3) the female POD: OOD: OCD = 12: 17: 21 (the female POD: OOD: OCD = 12: 13: 15); 4) the female PL: PW: LT I: WT I: HFL: HTL = 80: 14: 52: 64: 71: 88 (the female PL: PW: LT I: WT I: HFL: HTL = 69: 11: 41: 50: 60: 70); 5) the ocellus and vertex areas feature dense, midsized to large punctures (the ocellus and vertex area feature dense, fine punctures); 6) the scutum has dense, fine punctures anteriorly, dense and midsized to large punctures medially and posteriorly (the scutum has dense, fine punctures); 7) the petiole lacks a median longitudinal keel ventrally in the female (the petiole has median longitudinal keel); 8) the second recurrent vein ends in the third or interstitial submarginal cell (the second recurrent vein ends in the second submarginal cell). Description. Female. Body length 11.0– 11.8 mm. Black; mandible and pygidial area apically reddish brown; fore and mid tarsi dark brown. Appressed setae on clypeus golden or silvery, vertex, scutum, scutellum, and metanotum with long, dense, pale yellow pubescence. Setae on mesopleuron, legs, propodeum, and petiole mid length and silvery (Fig. 1 A, B). Head. In frontal view, clypeus with dense, fine punctures except margin, mid portion prominent with arch shallow emargination medially, basal 1 / 2 of clypeal disk moderately convex. HW: HLF: AOD: WAS: IAD = 102: 78: 10: 8: 14. Mandible bidentate apically, broad, blunt; width basally: medially: apically = 18: 10: 3. Interantennal tooth conspicuous, high, apex obtuse or slightly acute; frontal carina weak and reaching interantennal tooth around median ocellus (Fig. 1 C). Scape of antennae slightly bent, relative lengths of joints III – XII = 24–26, 16–17, 15–16, 15, 13–14, 12–13, 11–13, 11–12, 11–12, 16–17; joint III ~ 3.4–4.3 × as long as wide apically, joint IV with 2.0–2.4 ×, joint XII with 1.8–1.9 × (Fig. 1 D). Frons shiny with dense, fine to midsized punctures, and below anterior ocellus with weak longitudinal ridges (Fig. 1 C). In dorsal view, ocellus and vertex area shiny, with dense, midsized to large punctures, interspaces larger than frons; ocellar area not raised, behind postocelli with shallow sulcus, vertex behind postocelli region not raised, occipital carina without longitudinal ridge (Fig. 1 B, E). HW: HLD: POD: OOD: OCD = 102: 36: 12: 17: 21. Thorax. Scutum with dense, fine punctures anteriorly, dense, midsized to large punctures medially and posteriorly, interspaces 1–2 × as wide as diameter of puncture. Admedian lines and notauluses weak, nearly parallel (Fig. 1 F). Scutellum with dense, fine punctures, metanotum with sparse, microscopic punctures (Fig. 1 F). Propleuron with five or six short oblique striae, epicnemial areas shiny, with sparse, microscopic punctures, omaulus ending as it becomes ventral and below normally curved backwards. Mesopleura shiny with sparse, microscopic punctures, posteriorly without longitudinal striae (Fig. 1 G). Mesosternum without acetabular carina, with slightly strong, longitudinal medioventral carina, medially with one or two transverse carinae. Enclosed area of propodeum depressed, bordered by a narrow horizontal area which is distinctly separated from back of propodeum, horizontal area slightly wider on either side of sulcus, laterally with some sturdy oblique longitudinal carinae; propodeal pad with a smooth area, slightly wider on sides and narrower in middle (Fig. 1 F). Posterior surface of propodeum with sturdy reticulation, medially with deep sulcus reaching enclosed area, upper of sulcus with three or four transverse carinae (Fig. 1 H). In profile, dorsal surface of propodeum with posterior surface nearly obtuse angle, upper lateral surface of propodeum with oblique, short rugae (Fig. 1 G). Second recurrent vein ending in third or interstitial submarginal cell (Fig. 1 I). Hind tibia with a row of long, thick, brownish thorns on outer surface (Fig. 1 B). Gaster. PL: PW: LT I: WT I: HFL: HTL = 80: 14: 52: 64: 71: 88. Petiole nearly quadrate in cross section, slightly bent upwards basally, slightly widened backwards, width apically 2.2 × basally, dorsally completely smooth (Fig. 1 B, F). Lateral side with two slender longitudinal carinae and deeply depressed (Fig. 1 B); ventrally without median longitudinal keel. Gaster shiny, terga with sparse microscopic punctures. Pygidial area elongate-triangular, coriaceous, 1.8–2.1 × as long as wide basally, laterally one or two rows of coarse, midsized punctures and stiff bristles, apex truncate, slightly concave in middle, basally not convex (Fig. 1 J). Sterna smooth. Male. Similar to female, but body slender, smaller, body length 9.0–11.0 mm (Fig. 2 A, B). Mandible, fore and mid tibiae, and tarsi dark brown. Vertex and scutum with long, dense, palely yellow pubescence (Fig. 2 C). Gastral sterna III and IV without fasciculate setae on hind margin (Fig. 2 B). Clypeus mid prominent portion with arch shallow emargination in middle, two triangular protections in both sides; partially covering labrum. Frons shiny with dense, fine to midsized punctures, and below anterior ocellus with indistinct longitudinal ridges (Fig. 2 C). Ocellar area slightly raised (Fig. 2 A). Antennae slenderer than female, pedicel partially concealed within scape (Fig. 2 A); flagellomeres VII – X beneath with linear tyloids; relative lengths of joints III – XIII = 21–24, 18–20, 17–20, 17–20, 17–19, 16–18, 15–16, 17, 16, 15–17, 20–21; joint III ~ 2.6–3.0 × as long as wide apically, joint IV 2.1–2.5 ×, joint XII 1.6–2.0 × (Fig. 2 D). In frontal view, HW: HLF: AOD: WAS: IAD = 81: 61: 7: 8: 10; dorsal view, HW: HLD: POD: OOD: OCD = 81: 32: 11: 15: 16 (Fig. 2 C). Hind tibia without long, thick, brownish thorns on outer surface (Fig. 2 B). Petiole ventrally with median longitudinal keel medially and posteriorly, PL: PW: LT I: WT I: HFL: HTL = 70: 11: 43: 46: 53: 60. Genitalia large, yellowish brown, gonostyle slender and long, apical portion with inner (or dorsal) 1 / 2 turned into a semitransparent membrane, outer (or ventral) margin and apex provided with a fringe of sparse long setae (Fig. 2 I – L). Volsella divided into two branches medially, dorsal and ventral, each roundly curved and united with each other again at base of apical elongate body, cuspis flattened, hollowed ventrally, with apex gently rounded and turned ventrally, slightly produced on inner apical area. Distribution. China (Inner Mongolia, Shaanxi, Yunnan). Etymology. The specific name is derived from two Latin words: froni - (= frons) and - striatus (= striate), referring to the upper frons weakly striate.