Systematics And Integrative Taxonomy Of The Primitively Segmented Spider Genus Qiongthela(Araneae:Mesothelae:Liphistiidae)

The primitively segmented spider genus Qiongthela belongs to the Class Arachnida,the Order Araneae,the Suborder Mesothelae,the family Liphistiidae.Qiongthela spiders with long life span,limited dispersal abilities,and restricted habitats have been shown to be excellent model organism for testing historical biogeographical hypotheses.Until now,a few studies have been conducted on the systematics and phylogeny of the genus.However,the phylogenetic relationships within in the genus Qiongthela and taxonomic revision of Qiongthela have not been reported.Currently,there are only seven named Qiongthela species,five of which are known from Hainan Island,China,the other two of which,are distributed in southern Vietnam.Females have simple genitalia and show extremely intraspecific variations.Moreover,it is difficult to collect adult males in burrows in the field.All the above reasons made the species delimitation of the genus Qiongthela based sole on morphology challenging.Therefore,the objectives of this thesis are as follows:(1)Through targeted and extensive sampling to obtain a large number of Qiongthela samples,reconstruct the species-level phylogeny of Qiongthela based on molecular data,investigate the phylogenetic relationships of the genus;and(2)Using the integrative taxonomic method by combining molecular-based species delimitation approaches with classical morphological taxonomy to diagnose and describe the species of Qiongthela.I conducted four different molecular-based species delimitation methods based on the single-locus COI,that is two genetic-based methods,DNA barcoding gap and ABGD(automatic barcode gap discovery),and two tree-based methods,species delimitation plugin P ID(Liberal)and b PTP(Bayesian implementation of the Poisson tree processes(PTP)model).The results showed that DNA barcoding gap,ABGD and P ID(Liberal)support 21 species,yet b PTP gave 27 species.In addition,two mitochondrial genes(cytochrome c oxidase subunit ?(CO?),16 S r RNA(16S)),and three nuclear genes(internal transcribed spacer 2(ITS2),28 S r RNA(28S)and histone 3(H3)),were amplified and sequenced.I reconstructed the phylogeny of Qiongthela using maximum likelihood(ML)and Bayesian inference analyses(BI).The results strongly support the monophyly of the genus.Finally,integrate the molecular species delimitation and morphology,there are 23 Qiongthela species.Therefore,I diagnosed and redescribed seven known species,and described 16 new species based on morphological characters: Qiongthela baoting sp.nov.,Qiongthela daan sp.nov.,Qiongthela diaoluo sp.nov.,Qiongthela dongfang sp.nov.,Qiongthela fenghuang sp.nov.,Qiongthela limu sp.nov.,Qiongthela nankai sp.nov.,Qiongthela nanlan sp.nov.,Qiongthela nanmei sp.nov.,Qiongthela niudi sp.nov.,Qiongthela qifang sp.nov.,Qiongthela qiongzhong sp.nov.,Qiongthela sanya sp.nov.,Qiongthela shiyi sp.nov.,Qiongthela yalin sp.nov.,Qiongthela yinggezui sp.nov..In the summary,this study provides the first systematics and integrative taxonomy of the genus Qiongthela by combining molecular data with morphological characters.The results not only reveal the species diversity and phylogeny of this genus,but also further improved the phylogenetic relationships of the family Liphistiidae.