Neoperla xiangtoushana sp. nov.

(Figs. 4–8)

Diagnosis. The male aedeagus is C-shaped and lacks a ventral lobe. The aedeagal tube is smooth and strongly sclerotized. The aedeagal sac comprises approximately one-quarter of the length of the tube, features a small bulge at its base, and is mostly covered with coarse spines on the dorsal surface. The female subgenital plate possesses a pair of prominent, finger-like lobes.

Adult habitus (Fig. 4). Forewing length 13.5–14.0 mm, hindwing length 12.6–13.0 mm (n=3). Body color brown. Head yellow, with a prominent subrectangular dark brown ocellar patch and another dark brown triangular patch on anterior part of frons; palpi and antennae dark brown; biocellate, distance between ocelli ca. 1.5 x diameter of each ocellus; head slightly wider than pronotum (Fig. 4a). Pronotum rectangular, brown except for paler lateral area, with scattered indistinct rugosities; corners rounded (Fig. 4b). Wings brownish and transparent, with dark brown veins (Fig. 4a); legs dark brown, with femora mostly paler; cerci dark brown, with a pale basal part.

Male (Figs. 4c, 5–6). Posterior process of tergum 7 trapezoidal, covered with dense sensilla basiconica. Tergum 8 with a tongue-shaped upcurved process, with many sensilla basiconica at distal margin. Tergum 9 with two paramedian patches of long hairs with sparse sensilla basiconica. Hemitergal processes of tergum 10 slender, finger-like, slightly bent medially, with a sharp tip (Figs. 4c, 5a–c). Aedeagal tube heavily sclerotized and evenly curved ventrally (Figs. 5d, 6a). Aedeagal sac about a quarter of the length of the tube, distinctly curved ventrad with a blunt tip; a small swelling located in basal half; ventral surface mostly smooth and the remaining surface evenly covered with stout spines (Figs. 5d, 6b).

Female (Figs. 7–8). Forewing length 15.0–16.0 mm, hindwing length 13.6–14.5 mm (n=3). Habitus and head pigmentation generally similar to male (Figs. 7a–b). Subgenital plate of sternum 8 distinctly produced, subtriangular, bearing a deep semicircular mesal notch that forms a pair of finger-like lobes (Figs 7c, 8).

Eggs. Unknown. Females were void of mature eggs.

Type Material. Holotype: male (HIST), China: Guangdong Province, Huizhou City, Boluo County, Xiangtoushan National Nature Reserve, Xiaba Reservoir, 23°17'28" N, 114°25'35" E, 210m, 2024,VII.12, Raorao Mo, Yizhen Han, Haoqiang Zhang, Leyou Zhang, Sihan Li . Paratypes: 2 females (HIST), same data as holotype; 1 female (HIST), same locality and collector as above, Science and Education Park, 23°15'54" N, 114°22'22" E, 416 m, 2024,VII.12, light trap ; 1 male (HIST), Guangdong Province, Huizhou City, Huidong County, Lianhuashan Mountain, Baipenzhu Provincial Nature Reserve, Xinan Village, 23°2'59" N, 115°8'4" E, 380 m, 2024.VII.14, Meiying Lin ; 2 males (HIST), same locality as above, Feiwa Temple, 23°4'4" N, 115°14'9" E, 935 m, 2024,VII.16, light trap, Raorao Mo, Yizhen Han, Haoqiang Zhang, Leyou Zhang, Sihan Li .

Etymology. The name refers to the type locality, Xiangtoushan National Nature Reserve.

Distribution. China: Guangdong Province (Huizhou City). Known only from the type locality.

Remarks. The new species is similar to Neoperla anjiensis Yang & Yang, 1998 and N. shiwandashana Mo, Yao, Wang & Li, 2019 (Huo et al. 2021) in possessing similar terminalia and a simple, fully sclerotized aedeagal tube. The new species and N. anjiensis can be distinguished by comparing details of the aedeagal sac armature. In the new species (Figs. 5d, 6a–b), the aedeagal sac is strongly curved ventrally, forming a semicircular shape, and its dorsal surface is evenly covered with coarse spines of uniform size. In contrast, in N. anjiensis (Fig. 9b), the aedeagal sac curves at a right angle towards the ventral surface, and its dorsal surface is covered with spines of varying sizes. In addition, the new species can be easily distinguished from N. shiwandashana by its significantly longer aedeagal sac. In N. shiwandashana (Fig. 9c), the length of the aedeagal sac is approximately equal to the width of the aedeagal tube.