Concavapsocus valvaculeiformus Yang, Li, Ren & Yao, 2025, sp. nov.

Concavapsocus valvaculeiformus sp. nov. (Figs 1–2) Materials. All specimens are adult. Holotype: CNU-PSO-MA2015005, female, well-preserved. Paratype: CNU-PSO-MA2015006, female, well-preserved. CNU-PSO-MA2015007, male, body covered by many impurities, head and legs broken; CNU-PSO-MA2015008, male, terminalia blurred and covered by wings; CNU-PSO-MA2015009, female, wings broken. Locality and horizon. Hukawng Valley, Kachin State, Northern Myanmar. mid-Cretaceous, lowermost Cenomanian. Etymology. The species name is a combination of the Latin words “ valv- ” (valve) and “ aculeiformus ” (needle like), referencing the elongated needle-like structure of the ventral valves. Diagnosis. Distinct ecdysial line, lacinia developed with four apical teeth. Macropterous or brachypterous. Legs covered dense setae, tibiae with two apical spurs. Paraproct lacking anal spine; V1 slender, base unfused and tip sharp, needle-like apex, approximately three times the length of V2; V2 rod-like, twice as thick as V1; V3 short, broad and rounded, flanking ventral valve laterally; subgenital plate sparsely setose. Remarks. We assigned the new species to Concavapsocus Wang et al., 2019 based on the following characteristics: (1) ocelli absent; (2) antennae with 23-segmented; (3) mx2 and mx4 without conical sensillum; (4) lacinia developed; (5) forewings membranous, with several setae on veins and posterior margin; (6) basal portion of Sc short, ending free in membrane; (7) basal part of R 1 fused with R 2+3, A 1 fused with CuP near middle of forewing; (8) hind wing present, membranous; (9) coxae with several setae; one coxal rasp present; (10) tibiae with two apical spurs; tarsi with three-segmented. Therefore, the new specimens can be clearly classified into Concavapsocus. The differences between Concavapsocus valvaculeiformus sp. nov. and C. parallelus include: (1) C. valvaculeiformus with a prominent vertexal ecdysial cleavage line (vs. C. parallelus ecdysial cleavage line absent); (2) lacinia developed, bearing four teeth of nearly uniform size (vs. C. parallelus lacinia only with two apical teeth); (3) macropterous and brachypterous (vs. C. parallelus only has brachypterous); (4) paraproct without an anal spine (vs. C. parallelus paraproct with an anal spine); (5) V1 slender, the base unfused and the tip sharp, fine needle-like, approximately third times the length of V2, V2 rod-like, twice times thicker than V1, V3 short, broad and rounded, located on both sides of ventral valve, subgenital plate with few setae (vs. C. parallelus V1 reduced to rod-like, not sclerotized, V2 slender, needle-like, V3 broad without posterior setae, subgenital plate with dense setae, covering at most part of basal V3). Description. Head: Oval, width 0.2 mm, length 0.36 mm; dostinct vertexal ecdysial line, covered by long dense setae. Compound eyes well-developed, located on both ends of head, diameter 0.11 mm, IO/d=0.30, ocelli absent. Postclypeus broad, diameter longer than half of compound eyes. Antennae 23-segmented, with secondary annulation, ca. 1.12 mm long, scape and pedicel ca. 0.08 mm long, broader than flagellomeres; scape, pedicel, f1 and f2 with setae, f1: 0.10 mm, f2: 0.09 mm (Fig. 2A). Chewing mouthparts, maxillary palps four-segmented, ca. 0.29 mm long, mx2 and mx4 longest, mx1: 0.02mm, mx2: 0.10mm, mx3: 0.05mm, mx4: 0.12mm, mx4 rod-like, mx2 and mx3 with setae. Lacinia developed, with four apical teeth (left lacinia of CNU-PSO-MA2015006 with only three teeth visible); labial palps two-segmented, terminal segment rounded, thicker than maxillary palp and lacinia, ca. 0.08 mm long (Fig. 2B). Thorax: Neck relatively wider, with a transversely band-like pronotum exhibiting convex on the sides and concave in the middle. Wings: Macropterous, forewing 1.37 mm in length, 0.47 mm in width, with a length-to-width ratio of three to one; forewing vannal fold developed, subrectangular and apex concave inwardly, veins parallel, bearing setae. forewing Sc short, not reaching R or wing margin, ends in membrane at 0.18 mm, pterostigma absent; R with four branches, bifurcating into Rs and R 4+5 at 0.35mm distal of wing base, R 4+5 reaching wing margin at 1.35 mm, Rs bifurcating into R 1 and R 2+3 at 0.58 mm distal of wing base, R 2+3 bifurcating into R 2 and R 3 at 1.01 mm distal of wing base, reaching wing margin at 1.18 mm and 1.32 mm respectively; R fused with M basally, then bifurcate at 0.18 mm; base of CuA interrupted, M and CuA unbranched, reaching wing margin at 1.33 mm and 1.30 mm respectively; A unbranched, reaching wing margin at 0.88 mm; CuP and A 1 meeting at middle of wing at 0.38 mm at distal of wing base; posterior margin bearing setae. Hind wing present, 1.30 mm in length, 0.42 mm in width, membranous; Sc absent, R and M unbranched, reaching wing margin at 1.29 mm and 1.23 mm respectively, Cu bifurcating into CuA and CuP at 0.52 mm distal of wing base, A absent; radial cell absent (Fig. 2C). Leg: Coxae setose, hind legs with coxal rasp (Fig. 2D), tibiae bearing dense setae with two apical spurs; tarsi three-segmented (t1> t2> t3), t1 and t2 with spurs. Preapical claws simple, symmetrical without preapical tooth and pulvilli (Fig. 2E). Female genitalia: Paraproct without anal spine. V1 slender, base unfused apex needle-like, approximately third times the length of V2; V2 rod-like, and twice times thicker than V1; V3 short, broad and rounded, flanking valve laterally, subgenital plate with sparse setae (Fig. 2F, G).