Zapada kondratieffi sp. nov.

Figs. 1–9

Type material. Holotype male (ICJUST), Sichuan Province, Xiaojin County, Siguniangshan Town, Siguniang Mountain Scenic Area, an unnamed stream (Fig. 1A–C), 30.9336°N, 102.8845°E, alt. 4100 m, 16.VII.2021, Zhi-Teng Chen leg. Paratype: one male (ICJUST), same data as holotype .

Etymology. The new species is named after Dr. Boris C. Kondratieff, who has made great contributions to Plecoptera science.

Description. Measurements. Holotype: BL = 6.0 mm; FL = 6.5 mm; HL = 5.0 mm. Paratype: BL = 6.0 mm; FL = 6.0 mm; HL = 5.0 mm.

Head. Head dark (Figs. 2–3); two ocelli pale; compound eyes dark and protruding. Antennae dark brown, subequal in length to body. Mouthparts brown (Figs 3–4), maxillary palp slender, apical segment similar to previous two segments; labial palp strongly shortened (Fig. 4A); apical segment oval in shape. Cervix with five identical finger-shaped, simple gills (Fig. 4A–C); each lateral cervical sclerite with both inside and outside gills; an extra median gill present between lateral cervical sclerites.

Thorax. Thorax brown (Fig. 2). Pronotum subquadrate, surface brown with dark rugosities, corners obtuse; anterior margin truncate, posterior margin concave. Legs dark brown, distal ends of femur and tibia darker (Figs. 2–3).

Wings. Macropterous (Figs. 2–3), forewing membrane a translucent charcoal-gray, most cells with rounded pale spots; veins brown; margins of wings fringed with short bristles. Hindwings without spots. Both wing pairs with the X-structure typical of the family. In forewings, C strong and setose; h short and stout; Sc subapically nearly touching C, ScP joins RA before ra-rp; single crossvein present between C and Sc besides h; RA slightly curved, terminal costal crossvein joins RA after ra-rp; RP forked shortly after ra-rp; M forked basal to the fork of RP; joint of r-m and M interrupted; four to five crossveins present between M and CuA; six to seven crossveins present between CuA and CuP; CuP ended before half of wing length; cu-a present; AA1 sinuous, AA2 forked near midpoint. In hindwings, C, Sc, RA and RP similar to forewings; M forked distal to the fork of RP; m-cu and the single crossvein between CuA and CuP simple; CuP simple; anal area large and folded with five simple anal veins.

Abdomen. Abdominal segments 1‒7 pale brown, with medially interrupted anterior margins (Figs. 2–3). Tergum 7 with a deep, subtriangular anterior notch (Fig. 5A). Terga 8‒10 dark brown (Fig. 5A–D), with complete anterior margins. Tergum 9 shortened, with slightly concave anterior margin (Figs. 5A, 6A). Tergum 10 strongly sclerotized, with a broad membranous median area (Figs. 5A–D, 6A–F), posterior margin protruded medially and fused with two subtriangular lateral sclerites. Cerci reduced into a small rounded knob (Figs. 5–6); inner surface membranous, glabrous and concave; outer surface weakly sclerotized, covered with dense long spines; apex with a membranous circular area and a dark, stout apical spine.

Genitalia. Epiproct elongate-elliptical in both dorsal and ventral views (Fig. 7), extending to the anterior edge of T10, two membranous apical lobes extended posteriad along lateral margins. Median part of dorsal sclerite of epiproct near inverted V-shaped (Fig. 7A–B), anteriorly fused with ventral sclerite, posteriorly fused with paired lateral arms; lateral arms of dorsal sclerite directed obliquely and posteroventrally connected by a slender sclerite (Fig. 7C–D). Ventral sclerite of epiproct anteriorly fused with dorsal sclerite (Fig. 7E–F), gradually widened posteriad (Fig. 7G–H), medially with a longitudinal suture which widened posteriad, posterolateral extensions curved anterodorsally. Basal sclerite of epiproct near semicircular in both dorsal and ventral views (Fig. 7A, B, G, H), anteriorly with two small fusiform sclerites projecting anterolaterally (Fig. 7 E–F), laterally expanded into two hookshaped arms beneath ventral sclerite of epiproct (Fig. 7E–F). Vesicle of sternum 9 elliptical (Fig. 8A–B), pedicel short and constricted, margins sclerotized; hypoproct broad and elliptical (Fig. 8A–B), apex extended posteriad, forming a short median spine. Paraproct simple (Fig. 8A, C, D), outer lobe broad, beneath outer margin with an isolated hemispherical knob; inner lobe vestigial, reduced into a small posterior protuberance along inner margin.

Diagnosis. The new species can be easily distinguished from its Nearctic congeners by presence of five simple cervical gills and vestigial inner paraproct lobes (Baumann 1975, Baumann & Mingo 1987, Grubbs et al. 2015). It is closely related to the Asian Z. quadribranchiata (Zhiltzova, 1977) by sharing reduced inner paraproct lobes but can be distinguished by the bilobed epiproct apex and absence of Y-shaped structure on ventral epiproct sclerite apart from the unique presence of an extra median cervical gill (Zhiltzova 1977, Zhiltzova & Teslenko 2001).

Distribution. China: central Sichuan Province (Fig. 1A).