Rhopalopsole triangulis Li, Murányi & Yang, 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 : 168

Rhopalopsole triangulis Li, Murányi & Yang , sp. nov.

( Figs. 6–10 , 16 , 24–25 )

Diagnosis. This species is characterized by the lateral projections of tergum 10 being triangular in lateral view. The subanal lobe is distinctly sclerotized, medial bulge with narrow furrows. The putative female is recognized by the posterior margin of sternum 7 forming a trapezoid pregenital plate and sternum 8 with a wide transverse band.

Description. Forewing length ca. 6.6 mm in males, 7.0 mm in female (putative). Head and pronotum dark brown; compound eyes black; antennae and mouthparts brown. Thorax brown; wings hyaline; legs brown. Abdomen brown with terminalia dark brown.

Male ( Figs. 6–10 ). Tergum 9 weakly sclerotized medially and strongly so laterally, with strongly sclerotized strip along anterior margin, much wider than long, with two contacting triangular fields of scales at mid–posterior margin. Sternum 9 longer than width, basally with tongue–like vesicle bearing dense hairs, ca. 4X longer than width, apically with triangular trapezoidal subgenital plate. Tergum 10 central plate with three fused sclerites, the mesal sclerite slightly produced posteriorly contacting transverse bars, covered by macrotrichia and with sparse hairs, lateral ones are dark and longitudinally elongated, ca. 3X longer than wide; lateral projections incurved in dorsal aspect and upcurved in lateral view, basal third parallel-sided plate followed by an abrupt lower indention that is better seen in lateral view, the distal half gradually tapering forming a triangular plate, the lower face slightly indented in dorsal and lateral aspects. Cercus long and upturned without an apical spine. Epiproct slender and triangular, typical of the group. Subanal lobe distinctly sclerotized and bulb–like, medial bulge with narrow furrows in ventral view, distal portion membranous, with tapering apex after KOH treatment.

Putative female ( Fig. 16 ). Forewing length 7.0 mm. Posterior margin of sternum 7 produced in a trapezoidal darkly pigmented subgenital plate, the distal margins of the plate nearly straight. Sternum 8 with a transverse band almost across the posterior half of the segment.

Type Material. Holotype: male ( HIST): China, Guangxi Province, Wuming County, Damingshan National Natural Reserve, inflow stream above Dragon Lake , N23°29.751' E108°26.242', 1225m, 22.iii.2015 (/06), leg. J. Kontschán, J.Y. Li, S. Li, W.H. Li, D. Murányi, G.Q. Wang . Paratypes: 1♂ ( HNHM: No.PLO67): same data as holotype ; 1♀ ( HIST): Wuming County, Damingshan National Natural Reserve , vicinity of a restaurant at the tourist service area, N23°29.958' E108°26.085', 1215m, 21–22.iii.2015 (/02), leg. J. Kontschán, J.Y. Li, S. Li, W.H. Li, D. Murányi, G.Q. Wang ; 1♂ ( CAU): Wuming County, Damingshan National Natural Reserve , 2014. V.12, X.Y. Luo.

Etymology. The specific name refers to the triangular distal part of male tergum 10 lateral projections in lateral aspect.

Distribution. China, Guangxi; presently known only from the high plateau of the Daming Mountains, a rather isolated range in central Guangxi. The plateau is famous for 'tea-colored' waters caused by high humic content ( Fig. 25 ). The known habitats of the new species are these medium sized blackwater streams, co-occurring with only a few species of other stoneflies. The sympatric R. duyuzhoui was much more numerous than this apparently rare species ( Figs. 23–24 ).

Remarks. Males of the new species are distinguished from other members of the group by tergum 10 having lateral projections with distal part of lateral projection forming a triangular plate in lateral aspect. The species is similar to R. longispina known from Zhejiang and Guangdong in dorsal view. However, R. longispina has hooklike pointed tip lateral projections and lateral margins of subanal lobe form large paired parallel-sided or triangular sclerites ( Li & Yang 2012: figs. 32, 34–35 & 52).

Figures

FIGURES 6 – 10. Male terminalia of Rhopalopsole triangulis sp. nov., China, Guangxi, Damingshan National Natural Reserve— 6: terminalia, dorsal view; 7: terminalia, ventral view; 8: terminalia, lateral view; 9: upturned subanal lobe with distal portion of lateral projections before treatment with KOH, dorsal view; 10: tergum 10, lateral view.

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).