Zygoneura (Pharetratula) bidens

Zygoneura (Pharetratula) bidens (Mamaev, 1968) (Figs 4A–C) Pharetratula bidens Mamaev, 1968 [Mamaev (1968): 610; Mamaev (1976): 138; Gerbachevskaya-Pavluchenko (1986): 56; Menzel & Mohrig (1997): 62; Yagi & Sawada (2000): 36]. Pharetratula sinica Zhang & Yang, 1990 [Zhang & Yang (1990): 267]. Zygoneura (Pharetratula) bidens (Mamaev, 1968) [Menzel & Mohrig (2000): 585; Zhang et al. (2010): 42; Shin et al. (2014): 563; Huang et al. (2020): 360]. Material examined. 1♂, China, Inner Mongolia, Zhuozi, Baoan Linchang, 40°48’35.25’’ N, 112°16’51.11’’ E, 30.VIII.1987, leg. Chi-kun Yang [ZAFUBS001]. Remarks. Zhang & Yang (1990) identified Pharetratula sinica for the first and only time from China. Later, Menzel & Mohrig (2000) synonymized this species with Z. (Pharetratula) bidens (Mamaev). The holotype of this species is in a very poor condition, making it difficult to identify (Figs 4A–C). However, the figure plates provided by Zhang & Yang (1990) show that the apex of gonostylus in this species is highly curved, hook-like as compared to the oval, faintly curved gonostylus of Z. bidens (Zhang & Yang 1990: 268, Fig. 1E). Therefore, we assume that this can be a different species. For the moment, we still regard this morphological difference as intraspecific variability and continue to treat Pharetratula sinica Zhang & Yang as a junior synonym of Z. (Pharetratula) bidens (Mamaev) until additional morphologically identical specimens are discovered. Distribution. China: Inner Mongolia (Zhang & Yang 1990; Zhang et al. 2010), Korea (Shin et al. 2014), Russia (Mamaev 1968).