Rhopalopsole cestroidea Li, Murányi & Gamboa, 2017

Li, Weihai, Murányi, Dávid, Gamboa, Maribet, Yang, Ding & Watanabe, Kozo, 2017, New species and records of Leuctridae (Plecoptera) from Guangxi, China, on the basis of morphological and molecular data, with emphasis on Rhopalopsole, Zootaxa 4243 (1), pp. 165-176 : 170-172

Rhopalopsole cestroidea Li, Murányi & Gamboa , sp. nov.

(Figs. 11–15, 17–18, 22, 26–28)

Diagnosis. This species is characterized by the lateral projections of tergum 10 being bifurcate with the upper spine subequal to the lower one in lateral view. The cercus lacks apical spine and the epiproct is a transverse oblong with blade-shaped anterior margin in dorsal view. Females are diagnosed by posterior margin of sternum 7 forming slightly produced pregenital plate, medial portion with a backward directed sclerotized rod.

Description. Forewing length ca. 5.0 mm in males, 5.6 mm in females. Head brown, slightly wider than pronotum; compound eyes dark; antennae and mouthparts brown. Thorax brown, pronotum dark brown; wings infuscate; legs brown. Abdomen brown; vesicle, subanal lobe, epiproct and lateral projection dark brown.

Male (Figs. 11–15). Tergum 9 weakly sclerotized except anterior margin with sclerotized lateral third, medial ¼ with a large drop-like mid-anterior sclerite surrounded by lateral and posterior membranous area. Posteromedial margin terminates in a thin sclerite together with tiny granules. Sternum 9 longer than wide, distal portion with distinct trapezoidal subgenital plate; vesicle dark brown, tongue-like in dorsal view, ca. 2.5X longer than width in lateral view, covered with dense hairs. Tergum 10 with sclerotized, bifurcate lateral projections, terminating in a triangular upper spine and a similar, subequal lower spine in lateral view; central plate sclerotized, posterior half darker with a quadrate medial elevation with fine granules, transverse bars slightly elevated medially, generally rhomb-shaped, posterior margin sclerotized. Cercus slender, ca. 3X longer than width, gently curved dorsally, without spine. Epiproct strongly sclerotized, hatchet-shaped with waved anterior margin in dorsal view, wider than long and nearly as wide as central plate, anterolateral corners acute but posterolateral corners rounded, with a wide mesal notch posteriorly. Subanal lobe distinctly sclerotized basally, rounded apex membranous and slightly tapering, ventral furrows well defined.

Female ( Figs. 17–18 ). Posterior margin of sternum 7 forming a slightly produced pregenital plate, the plate bearing sclerotized, distal margin with fringed hairs and medial portion with a backward directed sclerotized rod. Sternum 8 membranous except a slender transverse medial strip covered with hairs.

Larva ( Fig. 27 ). Typical for the genus, delicate and pale, with relatively little and short setation. No specific characters can be discerned.

Type material. Holotype: male ( HIST): China, Guangxi Province, Shangsi County, Shiwandashan National Forest Park, Pearl River above tourist route bridge, N21°53.913' E107°54.283', 375m, 27.iii.2015 (/15), leg. J. Kontschán, J.Y. Li, S. Li, W.H. Li, D. Murányi, G.Q. Wang . Paratypes: 6♂ 10♀ (2♂ 6♀ HIST, 4♂ 4♀ HNHM (No.PLO83)): same data as holotype ; 2♂ 4♀ ( CAU): Shangsi County, Shiwandashan National Forest Park, 18.v.2013, leg. G.Q. Wang ; 2♀ ( HNHM: No.PLO94): Shangsi County, Shiwandashan National Forest Park, light trap on Yunwu Hotel balcony above Pearl River , N21°54.316' E107°54.203', 295m, 26–29.iii. 2015 (/14), leg. J. Kontschán, J.Y. Li, S. Li, W.H. Li, D. Murányi, G.Q. Wang ; 1♂ 5♀ ( HNHM: No.PLO88): Shangsi County, Shiwandashan National Forest Park, forest seeps by the Pearl River , N21°54.216' E107°54.240', 265m, 27– 29.iii.2015 (/16), leg. J. Kontschán, J.Y. Li, S. Li, W.H. Li, D. Murányi, G.Q. Wang ; 1♂ 8♀ ( HNHM: No.PLO93): Shangsi County, Shiwandashan National Forest Park, Pearl River below tourist route bridge, N21°54.122' E107°54.292', 315m, 27–29.iii.2015 (/17), leg. J. Kontschán, J.Y. Li, S. Li, W.H. Li, D. Murányi, G.Q. Wang ; 16♂ 23♀, 4 larvae ( HNHM: No.PLO119; 2♂ used for molecular studies): Shangsi County, Shiwandashan National Forest Park, small forest brook and the surrounding mountain forest, N21°50.574' E107°51.802', 365m, 28.iii.2015 (/20), leg. J. Kontschán, W.H. Li, D. Murányi, G.Q. Wang ; 1♀ ( HNHM: No. PLO121): Shangsi County, Shiwandashan National Forest Park, light trap above the confluence of Pinglong River and Minan River , N21°51.929' E107°50.675', 315m, 28.iii.2015 (/21), leg. J. Kontschán, W.H. Li, D. Murányi, G.Q. Wang .

Etymology. The specific name, “cestro-”, derived from Greek “kestron”, a graving tool, refers to the shape of epiproct in dorsal view.

Distribution and ecology. China, Guangxi; presently known only from the Shiwanda Mountains, a moderately high and isolated coastal range. This species occurred in large numbers associated with submontane rivers ( Fig. 28 ) and a small forest brook, together with a diverse community of other stoneflies, but the only other Leuctridae was R. sinensis Yang & Yang, 1993 . Many of the specimens were teneral and last instar larvae still occurred in the streams. This species apparently begins emerging in March ( Figs. 26–27 ). The species can be attracted to light.

Remarks. The new species seems a typical member of the R. vietnamica group, western assemblage sensu Sivec et al. (2008). The male of the new species seems closely related to R. hainana Li & Yang, 2010 from Hainan by sharing a quite similar epiproct but can be separated from the latter by lateral projections on tergum 10 with the upper spine being subequal to the lower one in lateral view and epiproct much wider than long and nearly as wide as central plate. R. hainana male epiproct is longer than wider and much narrower than central plate in dorsal view, the lateral projections on tergum 10 bearing a short upper spine and a larger lower spine in lateral view. Additionally, the cercus of the new species lacks a spine while that of R. hainana has a subapical spine.

Figures

FIGURES 16 – 21. Rhopalopsole spp. from China, Guangxi— 16: female terminalia, ventral view, putative R. triangulis sp. nov., Damingshan National Natural Reserve; 17: female terminalia, ventral view, R. cestroidea sp. nov., Shiwandashan National Forest Park; 18: same, lateral view; 19: female terminalia, ventral view, R. sinensis Yang & Yang, 1993, Shiwandashan National Forest Park; 20: basal portion of male antenna, R. furcospina (Wu, 1973), Neichao; 21: basal portion of male antenna, R. sinensis, Shiwandashan National Forest Park—scales 0.5 mm.

FIGURES 23 – 28. Rhopalopsole spp. and type localities from China, Guangxi— 23: R. duyuzhoui Sivec & Harper, 2008 male imago at the type locality of R. triangulis sp. nov.; 24: R. triangulis holotype male; 25: type locality of R. triangulis (Damingshan National Natural Reserve, inflow stream above Dragon Lake); 26: R. cestroidea sp. nov. male paratype imago at the type locality; 27: R. cestroidea pharate female larva at the type locality; 28: type locality of R. cestroidea (Shiwandashan National Forest Park, Pearl River at tourist road bridge).