Revision of the spider genus Jacaena Thorell, 1897, with descriptions of four new species from Thailand (Araneae: Corinnidae) Author Dankittipakul, Pakawin Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand; & Manukau Institute of Technology, Manukau, New Zealand; Author Tavano, Maria Museo Civico di Storia Naturale ‘ Giacomo Doria’, Genova, Italy Author Singtripop, Tippawan Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand; text Journal of Natural History 2013 2013-04-29 47 23 - 24 1539 1567 http://dx.doi.org/10.1080/00222933.2012.763059 journal article 55811 10.1080/00222933.2012.763059 dfc793f4-7033-4586-9849-718e7e526360 1464-5262 556127 97EFA23C-7537-4156-8EF0-2D38CF889F5B Jacaena thakek ( Jäger, 2007 ) comb. nov. ( Figures 1F , 5G–I , 10D–F ) Sesieutes thakek Jäger, 2007: 48 , figs 73–82, description of ♂ . Type material Holotype : ♂ , Laos , Khammouan Province , 9.5 km northeast of Thakek , 159 m , 17 ◦ 26.936 ′ N , 104 ◦ 52.499 ′ E , sieving leaf litter in front of cave , 30 October 2004 , P. Jäger and V. Vedel leg. ( SMF–56635 , examined, Figures 1F , 5G–I , 10D–F ). Diagnosis This species seems to be closest to J. mihun , because both species have very distinctly enlarged PME; their palps can be distinguished from other members of Jacaena by the pear-shaped bulb anteriorly narrowed, and the apex of the short, triangular conductor is pointing apically ( Figures 4G–I cf. 5G–I). The male of this species can be separated from that of J. mihun by the absence of a small, triangular denticle on the dorsal surface of the conductor ( Figure 10A cf. 10D). However, we have a private notion that the boundary between these two species is vague and J. thakek comb. nov. is possibly a junior synonym of J. mihun . Much larger samples would be needed to corroborate these slight differences as species-specific rather than intraspecific variation because more material recently obtained suggests that J. mihun has relatively broad distribution covering northern and north-eastern parts of Thailand (and most likely extending eastwards to Laos where J. thakek comb. nov. was collected). Distribution Known only from the type locality, Khammouan Province , Laos .