Phylogenomic Analysis of Ultraconserved Elements Resolves the Evolutionary and Biogeographic History of Segmented Trapdoor Spiders.

The segmented trapdoor spiders (Liphistiidae) are the sole surviving family of the suborder Mesothelae, which forms the sister lineage to all other living spiders. Liphistiids have retained a number of plesiomorphic traits and their present-day distribution is limited to East and Southeast Asia. Studying this group has the potential to shed light on the deep evolutionary history of spiders, but the phylogeny and divergence times of the family have not been resolved with confidence. We performed phylogenomic and molecular dating analyses of 2765 ultraconserved element loci from 185 liphistiid taxa. Our analyses show that the crown group of Liphistiidae appeared in the mid-Cretaceous at 102 Ma (95% credibility interval 92-113 Ma), but it was not until the Neogene that much of the diversification within the family occurred in mainland Southeast and East Asia. This diversification was coincident with tectonic events such as the extension of the East Asian continental margin, as well as geological upheavals in Indochina induced by the collision between India and Asia. Our study highlights the important role of major tectonic events in shaping the evolutionary history, present-day diversity, and geographical distribution of mesothele and liphistiid spiders. [biogeography; concatenation; Liphistiidae; molecular dating; summary coalescent; UCEs.].

A new species of Liphistius from Myanmar and description of the actual male of L. birmanicus Thorell, 1897 (Araneae, Mesothelae, Liphistiidae).

Five Liphistius Schiödte, 1849 species of the primitively segmented spider family Liphistiidae are currently known from Myanmar. Here, we described a new species, Liphistius pyinoolwin sp. nov. (♂♀), which was collected from Pyin Oo Lwin, Mandalay Region, Myanmar, diagnosed based on its genital morphology. The specimens (2♂♂, 5♀♀) collected by Walter C. Sedgwick from Pyin Oo Lwin in 1982 were misidentified as L. birmanicus Thorell, 1897 and are treated here as the newly described species. Accordingly, we described the males of L. birmanicus for the first time, redescribed its female, using newly collected specimens from Yadò, Than Taung and Kalekho Atet townships, Kayin State. We also provided information on the variation in genital morphology of both species, and their relationships within the birmanicus-group of species.

Two new species of the primitively segmented spider genus Liphistius Schiödte, 1849 (Mesothelae, Liphistiidae) from Myanmar.

Two Liphistius species of the primitively segmented spider family Liphistiidae, collected from Loikaw (Kayah State) and Pinlaung (Shan State), Myanmar, are diagnosed and described as new to science based on their genital morphology: Liphistius hpruso sp. nov. (♀), Liphistius pinlaung sp. nov. (♂♀).