Alloperla triquetra Rehman, Huo & Du sp. nov.

Figs 1, 2, 3

Type material.

Holotype, • 1 male China, Xiaodonggou Village, Benxi Autonomous County, Liaoning Province, 9–10-VI-2019, 589 m alt., 41°10.806'N, 124°40.148'E, leg. Huo Qing-Bo, Yang Yu-Ben (ICYZU) . Paratypes, • 4 males and 6 females (ICYZU), are the same as the holotype .

Diagnosis.

The new species is characterized by a triangular epiproct. The epiproct is distinctly triangular, especially in its middle portion. Basally, it is narrow and broadens medially before tapering towards a pointed apex, forming a triangular shape. The apex is pointed and bears tiny anterior hairs (Figs 1 B, C, 2 A).

Description.

Male. Forewing length: 8.5–9.0 mm; hindwing length: 7.5–8.0 mm. Body greenish in the field, pale yellow in ethanol. Head rounded brown with small central brown markings or spots. Compound eyes blackish, ocelli gray with black margins. Antennae brown, with pale brown basal segments (Fig. 1 A). Wings macropterous, hyaline. Abdominal terga 1–6 with a small brown median stripe. Tergum 9 dark brown posteriorly; tergum 10 dark brown, divided medially by the epiproct and reduced cowl into two hemitergal lobes bearing dense matting of long setae (Fig. 1 B). Epiproct small, triangular, with a dorsal surface covered by dense, small hairs. Basally narrow, widening medially to a triangular shape with a pointed apex (Fig. 1 C). The ventral surface is flattened, broad at the base, tapering towards apex, and bending towards tergum 10 to form a hook-like structure (Fig. 2 B, C). Laterally flattened, bearing small hairs. Cerci dark brown, generally brown with small basal segments covered with long setae.

Female. Forewing length: 9.0– 9.5 mm; hindwing length: 8.0– 8.5 mm. Body appears greenish in life and brown in ethanol. Head rounded, brown, with small brown markings or spots on frons. Compound eyes blackish, ocelli gray with black margins. Pronotum brown with slight rugosities (Fig. 3 A). Subgenital plate parallel-sided, rectangular at base, then abruptly narrows in middle, forming long subtriangle extending to middle of sternum 9. Posterior margins of plate rounded, and subgenital plate darkly sclerotized with black triangular spot in center (Fig. 3 B. C).

Egg and nymph. Unknown.

Distribution.

Known only from the type locality.

Etymology.

The species is named for its epiproct, which is distinctly triangular in shape. The Latin word “ triquetra ” means triangular.

Remarks.

The new species is most similar to Alloperla yangi Li & Wang, 2011, from Quanshanlinchang, Kuandian County, Liaoning, China, but it is easily distinguished by the structure of the epiproct. The epiproct of the new species is triangular with a pointed apex (Figs 1 B, 2 A). In contrast, the epiproct of A. yangi is tongue-shaped, rounded at the apex, and bears small apical setae (Li and Wang 2011: figs 1–9). The new species is also similar to A. teleckojensis Šámal, 1939, which is widely distributed in Russia and Mongolia. However, the epiproct of the new species is more prominent and broader than A. teleckojensis (Zhang et al. 2024: figs 92–95).