Isocapnia niuerheensis Yang & Du, 2024

Yang, Xiao & Du, Yu-Zhou, 2024, A new species of Isocapnia (Plecoptera: Capniidae) from China, with notes on I. apicispina Chen & Du, 2017 and I. arcuata Zhiltzova, 1975, Zootaxa 5471 (3), pp. 374-382 : 374-377

Isocapnia niuerheensis Yang & Du , sp. nov.

Figs. 1–5

Male. Body length 5.8–6.2 mm (n = 3). Wings micropterous ( Fig. 1 ). Head black with brown patches in posterior half, covered with small hairs, wider than pronotum; eye dark grayish with yellowish margin; ocelli pale brown; antennae and palpi light brown ( Fig. 2 ). Pronotum black, quadrate with dark brown margin ( Fig. 2 ). Legs light brown ( Fig. 2 )

Terga 5–10 with anterior margins sclerotized. Sternum 9 basally with drop-shaped and long vesicle bearing tiny hairs, apically with a triangular subgenital plate ( Fig. 3A ). Tergum 8 with a small protrusion in the center;. terga 9–10 medially with a curved triangular area ( Fig. 3B ). Tergum 10 constricted medially, with distinct anterior indentation and strongly sclerotized margins ( Fig. 3B ). Epiproct slender and long, sclerite upcurved, basely wider, and then fused into a slender sclerite almost straight but slightly curved backward anteriorly, apex slightly narrowed and ending without a distinctive structure ( Fig. 4 ). Cerci hairy and long ( Fig. 4 ).

Female. Unknown

Type materials. Holotype: ♂, China: Inner Mongolia, Niu’er Rivers ( Fig. 5 ), 901m, 51°34′52″N, 122°38′39″E, 2023-V-26, leg. Yang Xiao and Zhu Ya-Fei. Paratypes: 2 ♂♂, same data as holotype .

Etymology. The species is named after the type locality that Niuer River of Hanma Reserve.

Diagnosis. Isocapnia niuerheensis sp. nov. is mainly similar to I. guentheri , but are different due to characteristics of the epiproct. The epiproct of the I. guentheri has a small inward protrusion at the tip ( Fig. 6B ) but whereas I. niuerheensis sp. nov. lacks such a distinct protrusion ( Fig. 6A ). Isocapnia niuerheensis sp. nov. is also similar to I. anguis , but the new species has wings reduced in size and the vesicle is more slender. Isocapnia anguis is known only from Sichuan, southwest China, and is> 2000 km distant from the Niu’er Rivers of Inner Mongolia.

Figures

FIGURES 1. Isocapnia niuerheensis sp. nov. Male habitat, dorsal view.

FIGURES 2. Isocapnia niuerheensis sp. nov. Male head, dorsal view.

FIGURES 3. Isocapnia niuerheensis sp. nov. A. Male terminalia, ventral view; B. Male terminalia, dorsal view.

FIGURES 4. Isocapnia niuerheensis sp. nov. Male terminalia, lateral view.

FIGURE 5. Type locality stream of Isocapnia niuerheensis in Niu’er Rivers, Inner Mongolia, China (photo provided by Zhu Ya-Fei).

FIGURES 6. A. Isocapnia niuerhensis sp. nov. Apex of the epiproct; B. Isocapnia guentheri Apex of the epiproct (photo provided by Teslenko VA).