Molecular species delimitation in the primitively segmented spider genus Heptathela endemic to Japanese islands

Comparative Population Genomic Diversity and Differentiation in Trapdoor Spiders and Relatives (Araneae, Mygalomorphae)

Although patterns of population genomic variation are well-studied in animals, there remains room for studies that focus on non-model taxa with unique biologies. Here we characterise and attempt to explain such patterns in mygalomorph spiders, which are generally sedentary, often occur as spatially clustered demes and show remarkable longevity. Genome-wide single nucleotide polymorphism (SNP) data were collected for 500 individuals across a phylogenetically representative sample of taxa. We inferred genetic populations within focal taxa using a phylogenetically informed clustering approach, and characterised patterns of diversity and differentiation within- and among these genetic populations, respectively. Using phylogenetic comparative methods we asked whether geographical range sizes and ecomorphological variables (behavioural niche and body size) significantly explain patterns of diversity and differentiation. Specifically, we predicted higher genetic diversity in genetic populations with larger geographical ranges, and in small-bodied taxa. We also predicted greater genetic differentiation in small-bodied taxa, and in burrowing taxa. We recovered several significant predictors of genetic diversity, but not genetic differentiation. However, we found generally high differentiation across genetic populations for all focal taxa, and a consistent signal for isolation-by-distance irrespective of behavioural niche or body size. We hypothesise that high population genetic structuring, likely reflecting combined dispersal limitation and microhabitat specificity, is a shared trait for all mygalomorphs. Few studies have found ubiquitous genetic structuring for an entire ancient and species-rich animal clade.

Integrative species delimitation and five new species of lynx spiders (Araneae, Oxyopidae) in Taiwan

An accurate assessment of species diversity is a cornerstone of biology and conservation. The lynx spiders (Araneae: Oxyopidae) represent one of the most diverse and widespread cursorial spider groups, however their species richness in Asia is highly underestimated. In this study, we revised species diversity with extensive taxon sampling in Taiwan and explored species boundaries based on morphological traits and genetic data using a two-step approach of molecular species delimitation. Firstly, we employed a single COI dataset and applied two genetic distance-based methods: ABGD and ASAP, and two topology-based methods: GMYC and bPTP. Secondly, we further analyzed the lineages that were not consistently delimited, and incorporated H3 to the dataset for a coalescent-based analysis using BPP. A total of eight morphological species were recognized, including five new species, Hamataliwa cordivulva sp. nov., Hamat. leporauris sp. nov., Tapponia auriola sp. nov., T. parva sp. nov. and T. rarobulbus sp. nov., and three newly recorded species, Hamadruas hieroglyphica (Thorell, 1887), Hamat. foveata Tang & Li, 2012 and Peucetia latikae Tikader, 1970. All eight morphological species exhibited reciprocally monophyletic lineages. The results of molecular-based delimitation analyses suggested a variety of species hypotheses that did not fully correspond to the eight morphological species. We found that Hamat. cordivulva sp. nov. and Hamat. foveata showed shallow genetic differentiation in the COI, but they were unequivocally distinguishable according to their genitalia. In contrast, T. parva sp. nov. represented a deep divergent lineage, while differences of genitalia were not detected. This study highlights the need to comprehensively employ multiple evidence and methods to delineate species boundaries and the values of diagnostic morphological characters for taxonomic studies in lynx spiders.

Systematic notes on three new Luthela (Mesothelae, Heptathelidae) spiders from China, with their descriptions

Three new segmented trapdoor spider species belonging to the family Heptathelidae Kishida, 1923, i.e., Luthelaasukasp. nov. (♂♀, Sichuan), L.beijingsp. nov. (♂♀, Beijing), and L.kagamisp. nov. (♂♀, Sichuan), are described from China. Their phylogenetic position and relationships within Heptathelidae are tested and assessed using a combination available COI data downloaded from GenBank with new DNA sequences obtained in this study. The results show that the new species form a clade with eight known and one undescribed species of Luthela. High-definition illustrations of the male palps and female genitalia, diagnoses, and DNA barcodes are provided for these three new species, and their distributions are mapped.

An integrative approach reveals high species diversity in the primitively segmented spider genus

Accurate species delimitation is crucial for our understanding of evolution, biodiversity and conservation. However, morphology-based species delimitation alone appears to be prone to taxonomic errors and ineffective for taxa with high interspecific morphological homogeneity or intraspecific morphological variations, as is the case for mesothele and mygalomorph spiders. Combined molecular–morphology species delimitation has shown great potential to delimit species boundaries in such ancient lineages. In the present study, molecular and morphological evidence were integrated to delimit species of the primitively segmented spider genus Songthela Ono, 2000. The cytochrome c oxidase subunit I gene (COI) was sequenced for 192 novel specimens belonging to 12 putative morphospecies. The evolutionary relationships within Songthela and the 12-morphospecies hypothesis were tested in two steps – species discovery and species validation – using four single-locus species delimitation approaches. All species delimitation analyses supported the 12-species hypothesis. Phylogenetic analyses yielded three major clades in Songthela, which are consistent with morphology. Accordingly, we assigned 19 known and 11 new species (S. aokoulong, sp. nov., S. bispina, sp. nov., S. dapo, sp. nov., S. huayanxi, sp. nov., S. lianhe, sp. nov., S. lingshang, sp. nov., S. multidentata, sp. nov., S. tianmen, sp. nov., S. unispina, sp. nov., S. xiujian, sp. nov., S. zizhu, sp. nov.) of Songthela to three species-groups: the bispina-group, the multidentata-group and the unispina-group. Another new species, S. zimugang, sp. nov., is not included in any species groups, but forms a sister lineage to the bispina- and unispina-groups. These results elucidate a high species diversity of Songthela in a small area and demonstrate that integrating morphology with COI-based species delimitation is fast and cost-effective in delimiting species boundaries. http://zoobank.org/urn:lsid:zoobank.org:pub:AF0F5B31-AFAF-4861-9844-445AE8678B67

Does the Dzungarian racerunner ( Eremias dzungarica Orlova, Poyarkov, Chirikova, Nazarov, Munkhbaatar, Munkhbayar & Terbish, 2017) occur in China? Species delimitation and identification with DNA barcoding and morphometric analyses

The Eremias multiocellata-przewalskii species complex is a viviparous group in the genus Eremias, and a well-known representative of taxonomically complicated taxa. Within this complex, a new species - E. dzungarica (Orlova et al., 2017) - has been described recently from western Mongolia and eastern Kazakhstan, with an apparent distribution gap in northwestern China. In this study, we used an integrative taxonomic framework to address whether E. dzungarica indeed occurs in China. Thirty specimens previously classified as E. multiocellata were collected in eastern Kazakhstan and the adjacent Altay region in China. The cytochrome c oxidase I ( COI) barcodes were sequenced and compiled with those from Orlova et al. (2017) and analyzed with the standard and diverse barcoding techniques. We detected an absence of a barcoding gap in this complex, which indicates potential cryptic species in Eremias sp. 3 with high intraspecific diversity and multiple recently evolved species in Clade A. Both BIN and GMYC suggested an unrealistically large number of species (23 and 26, respectively), while ABGD, mPTP and BPP indicated a more conservative number of species (10, 12, and 15, respectively), largely concordant with the previously defined species-level lineages according to phylogenetic trees. Based on molecular phylogeny and morphological examination, all 30 individuals collected in this study were reliably identified as E. dzungarica - a distinct species - confirming the occurrence of this species in the Altay region, Xinjiang, China. Potentially owing to the larger sample size in this study, our morphological analyses revealed many inconsistencies with the original descriptions of E. dzungarica, which were primarily associated with sexual dimorphism and a broader range of values for various traits.