A taxonomic monograph of the liphistiid spider genus Heptathela, endemic to Japanese islands

Integrative taxonomic revision of the genera Nesticella and Howaia in Japan with the description of five new species (Araneae, Nesticidae, Nesticellini)

The Japanese species of the genera Nesticella Lehtinen & Saaristo, 1980 and Howaia Lehtinen & Saaristo, 1980 (Araneae, Nesticidae, Nesticellini) are revised using an integrative taxonomic approach. Their morphology, phylogenetic position within the genera, assignment to species groups, and distribution in mainland Japan and the Ryukyu islands are discussed herein. A phylogenetic and species delimitation analysis was conducted to confirm the boundaries between the putative species that were initially discriminated based on external and genital morphology. As a result of the present study, six species of Nesticella and three species of Howaia are proposed for the fauna of Japan based on the combined results of morphology and molecular analyses. Male and female of the previously known species H.mogera (Yaginuma, 1972), N.brevipes (Yaginuma, 1970), and N.okinawaensis (Yaginuma, 1979) are redescribed and illustrated using type specimens or specimens collected at the type locality. Nesticellaterrestris (Yaginuma, 1970) is resurrected as a valid species and distinguished from the closely related N.brevipes based on morphological and molecular evidence. The male of N.terrestris is described for the first time. We herein describe three new species of Nesticella and two new species of Howaia from different islands in the Ryukyu Archipelago, southwest Japan: N.insulanasp. nov. (♂, ♀) from Yonaguni-jima Island, N.occultasp. nov. (♀) from Ishigaki-jima Island, N.silvicolasp. nov. (♂, ♀) from Yakushima Island, H.albasp. nov. (♂, ♀) from Miyako-jima Island and H.subterraneasp. nov. (♀) from Okinoerabu-jima Island. Nesticellaoccultasp. nov., H.albasp. nov. and H.subterraneasp. nov. dwell exclusively in caves and show extensive morphological adaptation to subterranean life.

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

Integrative taxonomy reveals multiple lineages of the spider genus Cybaeus endemic to the Ryukyu Islands, Japan (Arachnida : Araneae : Cybaeidae)

The epigean spiders of the genus Cybaeus L. Koch, 1868 are known to have diversified in western North America and the Japanese Archipelago. To date, ~80 species of Cybaeus are known from Japan, but they have not previously been recorded from the Ryukyu Islands that harbour a diversity of endemic species. Here we describe eight new species of Cybaeus from the Ryukyu Islands, extending the range of Cybaeus southward to the central Ryukyus. Both sexes of each of the new species are described, and their phylogenetic relationships are estimated using nuclear and mitochondrial gene markers. Although Cybaeus okumurai, sp. nov. and C. kumadori, sp. nov. possess genital features that are common in the other Japanese congeners, the other six species (C. yakushimensis, sp. nov., C. kodama, sp. nov., C. amamiensis, sp. nov., C. aikana, sp. nov., C. tokunoshimensis, sp. nov., and C. hikidai, sp. nov.) are characterised by an elongated embolus and tubular spermathecae. These unique genital characteristics and the phylogeny recovered here suggest that these features evolved independently among the Japanese and Ryukyu Cybaeus species. Phylogenetic analyses highlight an unusual biogeographical pattern in which C. yakushimensis and C. kodama endemic to Yakushima Island in the northern Ryukyus are related to species distributed in the central Ryukyus. In contrast, our phylogeny suggests that C. okumurai from Tanegashima Island in the northern Ryukyus is sister to C. ashikitaensis (Komatsu, 1968), distributed in Kyushu of the Japanese Archipelago. The retreat constructs and sympatric distribution of Cybaeus found among the Ryukyus are also briefly discussed. ZooBank: urn:lsid:zoobank.org:pub:640D15AA-17F4-48EE-88B4-485CFF8FCD60

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

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.

Two new species of the primitively segmented spider genus Songthela from Hunan Province, China (Mesothelae, Liphistiidae)

This study reports two new species of the primitively segmented spider genus Songthela from Hunan Province, China, based on morphological characters: S.huangyangsp. nov. (♂♀), S.xiangnansp. nov. (♂♀). Additional material also facilitates a more accurate description of S.goulouensis (Yin, 2001) with the first description of the male. Nucleotide data for the barcoding gene, cytochrome c oxidase subunit I (COI), is also provided for these three species.