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Seven new species of the primitive segmented spider genus Liphistius are described and assigned to species groups based on characters of the male palp and vulva plate. The bristowei group includes L. dawei Sivayyapram & Warrit, sp. nov. (♂♀) from southeastern Myanmar, L. choosaki Sivayyapram & Warrit, sp. nov. (♀) from northwestern Thailand, and L. lansak Sivayyapram & Warrit, sp. nov. (♀) from western Thailand; the trang group (Complex A) contains L. kaengkhoi Sivayyapram & Warrit, sp. nov. (♂♀), L. hintung Sivayyapram & Warrit, sp. nov. (♂♀), L. buyphradi Sivayyapram & Warrit, sp. nov. (♂♀), and L. champakpheaw Sivayyapram & Warrit, sp. nov. (♂♀) from central Thailand.

A time scale of phylogenetic relationships contributes to a better understanding of the evolutionary history of organisms. Herein, we investigate the temporal divergence pattern that gave rise to the poor species diversity of the spider genus Solenysa in contrast with the other six major clades within linyphiids. We reconstructed a dated phylogeny of linyphiids based on multi-locus sequence data. We found that Solenysa diverged from other linyphiids early in the Cretaceous (79.29 mya), while its further diversification has been delayed until the middle Oligocene (28.62 mya). Its diversification trend is different from all of the other major lineages of linyphiids but is closely related with the Cenozoic ecosystem transition caused by global climate changes. Our results suggest that Solenysa is a Cretaceous relict group, which survived the mass extinction around the K-T boundary. Its low species diversity, extremely asymmetric with its sister group, is largely an evolutionary legacy of such a relict history, a long-time lag in its early evolutionary history that delayed its diversification. The limited distribution of Solenysa species might be related to their extreme dependence on highly humid environments.

Determining species boundaries forms an important foundation for biological research. However, the results of molecular species delimitation can vary with the data sets and methods that are used. Here we use a two-step approach to delimit species in the genus Heptathela , a group of primitively segmented trapdoor spiders that are endemic to Japanese islands. Morphological evidence suggests the existence of 19 species in the genus. We tested this initial species hypothesis by using six molecular species-delimitation methods to analyse 180 mitochondrial COI sequences of Heptathela sampled from across the known range of the genus. We then conducted a set of more focused analyses by sampling additional genetic markers from the subset of taxa that were inconsistently delimited by the single-locus analyses of mitochondrial DNA. Multilocus species delimitation was performed using two Bayesian approaches based on the multispecies coalescent. Our approach identified 20 putative species among the 180 sampled individuals of Heptathela . We suggest that our two-step approach provides an efficient strategy for delimiting species while minimizing costs and computational time.

Specimens of Araneae which the Department of Zoology, National Museum of Nature and Science, holds