japonica -group

Yu, Hao, Zhang, Jianshuang & Chen, Jian, 2017, Checklist of the Clubionajaponica-group spiders, with the description of a new species from China (Araneae, Clubionidae), ZooKeys 715, pp. 1-16 : 3

The japonica -group

Diagnosis.

In general, members of the japonica -group can be recognized by the following combination of characters (see also Dankittipakul and Singtripop 2008): dark colour pattern of carapace and dorsum of opisthosoma (Figs 1-3); the male retrolateral tibial apophysis small and not branched (Figs 5, 10), the sperm duct is sinuate and distinct (Figs 6-7), the embolus filiform or reduced (Figs 4-9, 11), the conductor sclerotized with variable shapes (e.g. a small tubercle in C. picturata Deeleman-Reinhold, 2001, long and filiform in C. biembolata Deeleman-Reinhold, 2001 and C. filicata O. Pickard-Cambridge, 1874, large and beak-shaped in C. japonica L. Koch, 1878 and C. grucollaris sp. n., Figs 4-12); the female epigyne has a relatively large atrium situated anteriorly, and the copulatory openings are located in rebordered groove of atrial margin (Fig. 13). The japonica -group resembles the corticalis -group in having the similar simple palp bulb in male, the atrium and copulatory openings located anteriorly in female, however, the latter can be distinguished from the former by: (1) the lack of a colour pattern on the opisthosoma; (2) the presence of a inflated tegulum with indistinct sperm duct; (3) the conductor membranous or absent; (4) the presence of a ventral tibial apophysis in many species; (5) the atrium is significantly smaller or absent; (6) copulatory openings are often located at anterior part of the epigynial plate, instead of close to the middle part in the japonica -group. All the provided corticalis -group characters are according to Deeleman-Reinhold (2001) and recent clubionid papers such as Wu and Zhang (2014) and Liu et al. (2016).

Taxonomic notes.

Dankittipakul and Singtripop (2008) divided the Southeast Asia japonica -group into two lineages. It appears that this standard of division may also apply to the japonica -group from China. The species of the 1st lineage have a large sclerotized and beak-shaped conductor that aligned transversely on apical part of the bulb (Figs 4-6, 15-17), such as C. circulata Zhang & Yin, 1998, C. calycina Wu & Zhang, 2014 and C. grucollaris sp. n., etc. Members of the 2nd lineage share the following characters: the reduced embolus; a long and filiform conductor; and the embolus and conductor fused with each other, forming an apical appendage together and situated on the apical portion of the tegulum (Figs 7-12). The 2nd lineage includes C. filicata and C. filoramula Zhang & Yin, 1998.

In spite of the variable conductor in the male palp, the female genitalia of the two different lineages are very similar. The epigynial plate has a large atrium situated anteriorly, and the atrium is bounded by an atrial margin. The posterior atrial margins are often not rebordered. Copulatory openings relatively small, located in rebordered groove of basolateral atrial margin (Figs 13, 18). Vulva consisting of anterior spermathecae and posterior bursae. The bursae are membranous, larger than the spermathecae (Figs 14, 19).

Strictly based on the group characters, figures and text descriptions of 495 Clubiona species were checked one by one. In this work, we focused on ungrouped species, but also considered grouped species based on previous infrageneric revisions ( Mikhailov1990, 1991, 1995, 2002; Deeleman-Reinhold 2001). As a result, there are at least 31 japonica -group species all over the world (but mainly distributed in Asia) at present, among which 9 species were recorded from China, including a new species described here as Clubiona grucollaris sp. n. (see Table 1).