Baiyuerius chongzu -species group

Diagnosis. Males of the species in this group can be identified by 1) the long and sharp lateral tibial apophysis and retrolateral apophysis (Figs 3C, 5C, 11C; figs 12, 24 in Xu and Li 2007; fig. 5E in Liu et al. 2020; figs 1C, 6G in Luo et al. 2023); 2) dorsal margin of cymbial furrow extended anteriorly (Figs 3C, 5C; figs 5E, 7C in Liu et al. 2020; figs 1C, 6G in Luo et al. 2023); 3) process of dorsal margin of conductor extremely large and separate from dorsal margin by a basal stalk (reduced in B. processus comb. nov. and B. yuelu Luo, Lu, Zhang & Wang, 2023) (Figs 3B, 5B, 11B; figs 5D, 7B in Liu et al. 2020; figs 1B, 6F in Luo et al. 2023). Females of the species in chongzu -group can be identified by 1) epigynal plate large, the length of epigynal pocket subequal to the width (except B. shenzhen Luo, Lu, Zhang & Wang, 2023), and epigynal teeth present (Fig. 9A, 13A, 15A; figs 2A, 3A, 6C in Luo et al. 2023); 2) copulatory ducts relatively long, no less than width of spermathecae, blind sacs long and curved (Fig. 9B, 13B, 15B; figs 2B, 3B, 6D in Luo et al. 2023).

Notes. The males of B. loong sp. nov. and B. processus comb. nov. appear differently from the other chongzuspecies group, their basal stalks of the process of the conductor’s dorsal margin are reduced or not remarkable, and their processes are in strange shape, seem like a shark fin, and even hardly separated from the dorsal margin in B. processus comb. nov. (Fig. 11B–E; figs 24, 25 in Xu & Li, 2007). Additionally, these two species exhibit a more southern distribution pattern, which nears Vietnam, far away from others, which indicates they might be classified into a new group. But the females of B. loong sp. nov. extremely resemble B. chongzu sp. nov. and B. rugosas (Wang, Peng & Kim, 1996), especially the present of the epigynal teeth. With comprehensive consideration, we place them in chongzu -species group temporarily.

Distribution. China (Hubei Province, Hunan Province, Gansu Province, Guangxi Zhuang Autonomous Region, Guizhou Province, Jiangxi Province, Shaanxi Province and Yunnan Province).

Species included. Eleven species are included in this group: Baiyuerius acroprocessus (Zhang, Zhu & Wang, 2017), Baiyuerius arcticus sp. nov., Baiyuerius chongzu sp. nov., Baiyuerius globasus (Wang, Peng & Kim, 1996), Baiyuerius imitatus sp. nov., Baiyuerius loong sp. nov., Baiyuerius processus (Xu & Li, 2007) comb. nov., Baiyuerius rugosas (Wang, Peng & Kim, 1996), Baiyuerius shaanensis sp. nov., Baiyuerius subyanlingensis (Liu & Xu, 2020) comb. nov. and Baiyuerius yuelu Luo, Lu, Zhang & Wang, 2023 .