Integrative taxonomy of the primitively segmented spider genusGanthela(Araneae: Mesothelae: Liphistiidae): DNA barcoding gap agrees with morphology

Genetic barcodes for species identification and phylogenetic estimation in ghost spiders (Araneae: Anyphaenidae: Amaurobioidinae)

The identification of spider species presents many challenges, since in most cases the characters used are from genital structures that are only fully developed in the adult stage, hence the identification of immatures is most often not possible. Additionally, these structures usually also present some intra-specific variability, which in some cases makes the identification of closely related species difficult. The genetic barcode technique (DNA barcodes), based on sequencing of the mitochondrial marker cytochrome c oxidase subunit I (COI ), has proven a useful, complementary tool to overcome these limitations. In this work, the contribution of DNA barcoding to the taxonomy of the subfamily Amaurobioidinae is explored using the refined single linkage analysis (RESL) algorithm for the delimitation of operational taxonomic units (OTUs), in comparison with the assemble species by automatic partitioning (ASAP) algorithm, and presented in conjunction with an updated molecular phylogenetic analysis of three other markers (28S rRNA, 16S rRNA, Histone H3 ), in addition to COI . Of a total of 97 included species identified by morphology, 82 species were concordant with the operational taxonomic units obtained from RESL, representing an 85% correspondence between the two methods. Similar results were obtained using the ASAP algorithm. Previous observations of morphological variation within the same species are supported, and this technique provides new information on genetic structure and potentially cryptic species. Most of the discrepancies between DNA barcoding and morphological identification are explained by low geographic sampling or by divergent or geographically structured lineages. After the addition of many specimens with only COI data, the multi-marker phylogenetic analysis is consistent with previous results and the support is improved. The markers COI , closely followed by 28S , are the most phylogenetically informative. We conclude that the barcode DNA technique is a valuable source of data for the delimitation of species of Amaurobioidinae, in conjunction with morphological and geographic data, and it is also useful for the detection of cases that require a more detailed and meticulous study.

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

Four new species of the primitively segmented spider genus Songthela (Mesothelae, Liphistiidae) from Chongqing Municipality, China

This paper reports four new species of the primitively segmented spider genus Songthela from Chongqing Municipality, China, based on morphological characters of both males and females: S. jinyun sp. nov., S. longbao sp. nov., S. serriformis sp. nov. and S. wangerbao sp. nov. We also provide the GenBank accession codes of mitochondrial DNA barcode gene, cytochrome c oxidase subunit I (COI), for the holotype of four new species for future identification.  

Phylogenomics and loci dropout patterns of deeply diverged Zodarion ant-eating spiders suggest a high potential of RAD-seq for genus-level spider phylogenetics

RAD sequencing yields large amounts of genome-wide data at a relatively low cost and without requiring previous taxon-specific information, making it ideal for evolutionary studies of highly diversified and neglected organisms. However, concerns about information decay with phylogenetic distance have discouraged its use for assessing supraspecific relationships. Here, using Double Digest Restriction Associated DNA (ddRAD) data, we perform the first deep-level approach to the phylogeny of Zodarion, a highly diversified spider genus. We explore the impact of loci and taxon filtering across concatenated and multispecies coalescent reconstruction methods and investigate the patterns of information dropout in reference to both the time of divergence and the mitochondrial divergence between taxa. We found that relaxed loci-filtering and nested taxon-filtering strategies maximized the amount of molecular information and improved phylogenetic inference. As expected, there was a clear pattern of allele dropout towards deeper time and mitochondrial divergences, but the phylogenetic signal remained strong throughout the phylogeny. Therefore, we inferred topologies that were almost fully resolved, highly supported, and noticeably congruent between setups and inference methods, which highlights overall inconsistency in the taxonomy of Zodarion. Because Zodarion appears to be among the oldest and most mitochondrially diversified spider genera, our results suggest that ddRAD data show high potential for inferring intra-generic relationships across spiders and probably also in other taxonomic groups.

Three new species of the primitively segmented spider genus Songthela (Araneae, Mesothelae) from Guizhou Province, China

We diagnose and describe three new species of the primitively segmented spider genus Songthela from Guizhou Province, China, based on morphological characters and molecular data: S.liuisp. nov. (♂♀), S.tianzhusp. nov. (♂♀), and S.yupingsp. nov. (♂♀). We provide the genetic distances within and among the three new species based on the DNA barcode gene, cytochrome c oxidase subunit I (COI) to support our descriptions. We also provide the COI GenBank accession codes for the three new species for future identification.

Three new species of the segmented spider genus Qiongthela (Mesothelae, Liphistiidae) from Hainan Island, China

We report three new species of the segmented trapdoor spider genus Qiongthela Xu & Kuntner, 2015 collected from Hainan Island, China based on morphological characters: Q.dongfangsp. nov. (♂♀), Q.nankaisp. nov. (♂♀), Q.yalinsp. nov. (♂♀). We also provide the GenBank accession codes of the DNA barcode gene, cytochrome c oxidase subunit I (COI), of the type specimens of all three new species to aid future identification.

DNA barcoding and species delimitation of butterflies (Lepidoptera) from Nigeria

Accurate identification of species is a prerequisite for successful biodiversity management and further genetic studies. Species identification techniques often require both morphological diagnostics and molecular tools, such as DNA barcoding, for correct identification. In particular, the use of the subunit I of the mitochondrial cytochrome c oxidase (COI) gene for DNA barcoding has proven useful in species identification for insects. However, to date, no studies have been carried out on the DNA barcoding of Nigerian butterflies. We evaluated the utility of DNA barcoding applied for the first time to 735 butterfly specimens from southern Nigeria. In total, 699 DNA barcodes, resulting in a record of 116 species belonging to 57 genera, were generated. Our study sample comprised 807 DNA barcodes based on sequences generated from our current study and 108 others retrieved from BOLD. Different molecular analyses, including genetic distance-based evaluation (Neighbor-Joining, Maximum Likelihood and Bayesian trees) and species delimitation tests (TaxonDNA, Automated Barcode Gap Discovery, General Mixed Yule-Coalescent, and Bayesian Poisson Tree Processes) were performed to accurately identify and delineate species. The genetic distance-based analyses resulted in 163 well-separated clusters consisting of 147 described and 16 unidentified species. Our findings indicate that about 90.20% of the butterfly species were explicitly discriminated using DNA barcodes. Also, our field collections reported the first country records of ten butterfly species-Acraea serena, Amauris cf. dannfelti, Aterica galena extensa, Axione tjoane rubescens, Charaxes galleyanus, Papilio lormieri lormeri, Pentila alba, Precis actia, Precis tugela, and Tagiades flesus. Further, DNA barcodes revealed a high mitochondrial intraspecific divergence of more than 3% in Bicyclus vulgaris vulgaris and Colotis evagore. Furthermore, our result revealed an overall high haplotype (gene) diversity (0.9764), suggesting that DNA barcoding can provide information at a population level for Nigerian butterflies. The present study confirms the efficiency of DNA barcoding for identifying butterflies from Nigeria. To gain a better understanding of regional variation in DNA barcodes of this biogeographically complex area, future work should expand the DNA barcode reference library to include all butterfly species from Nigeria as well as surrounding countries. Also, further studies, involving relevant genetic and eco-morphological datasets, are required to understand processes governing mitochondrial intraspecific divergences reported in some species complexes.

Machine learning approaches identify male body size as the most accurate predictor of species richness

BACKGROUND

A major challenge in biodiversity science is to understand the factors contributing to the variability of species richness -the number of different species in a community or region - among comparable taxonomic lineages. Multiple biotic and abiotic factors have been hypothesized to have an effect on species richness and have been used as its predictors, but identifying accurate predictors is not straightforward. Spiders are a highly diverse group, with some 48,000 species in 120 families; yet nearly 75% of all species are found within just the ten most speciose families. Here we use a Random Forest machine learning algorithm to test the predictive power of different variables hypothesized to affect species richness of spider genera.

RESULTS

We test the predictive power of 22 variables from spiders' morphological, genetic, geographic, ecological and behavioral landscapes on species richness of 45 genera selected to represent the phylogenetic and biological breath of Araneae. Among the variables, Random Forest analyses find body size (specifically, minimum male body size) to best predict species richness. Multiple Correspondence analysis confirms this outcome through a negative relationship between male body size and species richness. Multiple Correspondence analyses furthermore establish that geographic distribution of congeneric species is positively associated with genus diversity, and that genera from phylogenetically older lineages are species poorer. Of the spider-specific traits, neither the presence of ballooning behavior, nor sexual size dimorphism, can predict species richness.

CONCLUSIONS

We show that machine learning analyses can be used in deciphering the factors associated with diversity patterns. Since no spider-specific biology could predict species richness, but the biologically universal body size did, we believe these conclusions are worthy of broader biological testing. Future work on other groups of organisms will establish whether the detected associations of species richness with small body size and wide geographic ranges hold more broadly.

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.

Four new species of the primitively segmented spider genus Qiongthela from Hainan Island, China (Mesothelae, Liphistiidae)

The primitively segmented spider genus Qiongthela Xu & Kuntner, 2015 consists of seven species that are distributed in Hainan Island, China and southern Vietnam. Of the seven species, five are known from Hainan Island. In this study, four more Qiongthela species collected from Hainan Island are diagnosed and described as new to science based on morphological characters: Q. baoting sp. nov. (♂♀), Q. qiongzhong sp. nov. (♂♀), Q. sanya sp. nov. (♂♀), Q. yinggezui sp. nov. (♂♀). To facilitate future identification, the GenBank accession codes of the DNA barcode gene, cytochrome c oxidase subunit I (COI), for all the type specimens are also provided.

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

Among the eight extant genera of primitively segmented spiders, family Liphistiidae, two are confined to East Asian islands, Heptathela Kishida, 1923 and Ryuthela Haupt, 1983. In this paper, a taxonomic revision of the genus Heptathela (Heptathelinae) from Kyushu and Ryukyu archipelago, Japan is provided. This study follows a multi-tier species delimitation strategy within an integrative taxonomic framework that is presented in a parallel paper, in which diagnosable lineages are considered as valid species. There, the initial hypothesis of species diversity (19) based on classical morphological diagnoses is tested with multiple species delimitation methods aimed at resolving conflict in data. This revision follows those analyses that converge on the species diversity of 20, which includes a pair of cryptic species that would have been undetected with morphology alone. After this revision, eight previously described species remain valid, two junior synonyms are proposed, and 12 new Heptathela species are described based on diagnostic evidence. To ease identification and to hint at putative evolutionary units, Heptathela is divided into three groups. The Kyushu group contains H.higoensis Haupt, 1983, H.kikuyai Ono, 1998, H.kimurai (Kishida, 1920), and H.yakushimaensis Ono, 1998; the Amami group contains H.amamiensis Haupt, 1983, H.kanenoi Ono, 1996, H.kojimasp. nov., H.sumiyosp. nov., and H.ukensp. nov.; and the Okinawa group contains H.yanbaruensis Haupt, 1983, H.ahasp. nov., H.gayozansp. nov., H.kubayamasp. nov., H.maesp. nov., H.otohasp. nov., H.shurisp. nov., H.tokashikisp. nov., H.untensp. nov., and H.cryptasp. nov.Heptathelahelios Tanikawa & Miyashita, 2014 is not assigned to a species group. A combination of diagnostic tools augments the morphological diagnoses that, in isolation, would be prone to error in morphologically challenging groups of organisms.

Comparative morphology refines the conventional model of spider reproduction

Our understanding of spider reproductive biology is hampered by the vast anatomical diversity and difficulties associated with its study. Although authors agree on the two general types of female spider genitalia, haplogyne (plesiomorphic) and entelegyne (apomorphic), our understanding of variation within each group mostly concerns the external genital part, while the internal connections with the reproductive duct are largely unknown. Conventionally and simplistically, the spermathecae of haplogynes have simple two-way ducts, and those of entelegynes have separate copulatory and fertilization ducts for sperm to be transferred in and out of spermathecae, respectively. Sperm is discharged from the spermathecae directly into the uterus externus (a distal extension of the oviduct), which, commonly thought as homologous in both groups, is the purported location of internal fertilization in spiders. However, the structural evolution from haplo- to entelegyny remains unresolved, and thus the precise fertilization site in entelegynes is ambiguous. We aim to clarify this anatomical problem through a widely comparative morphological study of internal female genital system in entelegynes. Our survey of 147 epigyna (121 examined species in 97 genera, 34 families) surprisingly finds no direct connection between the fertilization ducts and the uterus externus, which, based on the homology with basal-most spider lineages, is a dead-end caecum in entelegynes. Instead, fertilization ducts usually connect with a secondary uterus externus, a novel feature taking over the functional role of the plesiomorphic uterus externus. We hypothesize that the transition from haplo- to entelegyny entailed not only the emergence of the two separate duct systems (copulatory, fertilization), but also involved substantial morphological changes in the distal part of the oviduct. Thus, the common oviduct may have shifted its distal connection from the uterus externus to the secondary uterus externus, perhaps facilitating discharge of larger eggs. Our findings suggest that the conventional model of entelegyne reproduction needs redefinition.

Four new species of the trapdoor spider genus Conothele Thorell, 1878 (Araneae, Halonoproctidae) from China

Herein four species of the trapdoor spider genus Conothele Thorell, 1878 collected from China are described as new to science based on the female genital morphology: C.baisha sp. n. (Hainan Province), C.baoting sp. n. (Hainan Province), C.linzhi sp. n. (Tibet), and C.jinggangshan sp. n. (Jiangxi Province). For two Hainan species, C.baisha sp. n. and C.baoting sp. n., between which it is difficult to distinguish solely based on female genital morphology, additional diagnoses derived from species-specific nucleotide substitution information and genetic distances using the mitochondrial gene, cytochrome c oxidase subunit I are provided.

Phylogeny and molecular species delimitation of long-nosed armadillos (Dasypus: Cingulata) supports morphology-based taxonomy

The armadillo genus Dasypus is the most species-rich and widely distributed genus of the order Cingulata and it has a dynamic taxonomic history. Recent morphology-based studies have proposed new taxonomic arrangements, but these were not yet assessed with molecular data. The two comprehensive phylogenetic hypotheses available for the genus are conflicting and were each based on a subset of taxa, hampering a proper evaluation of species boundaries. Using a multilocus molecular dataset, based on the broadest geographic sampling of Dasypus to date, we inferred the phylogenetic relationships of all species of the genus, including the recently reinstated D. beniensis and D. pastasae. We tested recent taxonomic hypotheses using several species-delimitation approaches. Our phylogeny recovered three main lineages of long-nosed armadillos that we treat as subgenera (Hyperoambon, Muletia and Dasypus) and identified the majority of its diversification as having occurred during the Pliocene. Molecular species delimitation supported morphological evidence in assigning D. hybridus as a subspecies of D. septemcinctus and confirming the split of the D. kappleri complex into three species. Our results strongly support the recognition of Guiana Shield populations formerly assigned to D. novemcinctus as a distinct species. The phylogenetic positions of D. mazzai and D. sabanicola remain uncertain. Further investigation using faster-evolving genes and additional samples may help to clarify the relationships of these young species.

Evaluating the accuracy of morphological identification of insect pests of rice crops using DNA barcoding

Accurate identification of agricultural pests is key requirement for the successful integrated pest management (IPM) program. However, due to limitations of conventional morphological methods, other molecular method like DNA barcoding is used. The current study was designed to evaluate the accuracy of morphological identification of insect pests using DNA barcoding. Morphologically, a total of 247 insect pests, representing 10 families, 18 genera, 22 species were identified. However, molecular identifications confirmed the presence of 11 families, 16 genera, and 20 species of agricultural pests. A total of 59 specimens were processed for DNA barcoding but genomic sequences of mt COI gene up to 600 bp were revived from 48 samples. Specimens that were misidentified through morphological studies were placed to their appropriate taxon, using this molecular approach. Results revealed the existence of clear barcode gap for different pest species. Moreover, the values of distance with the nearest neighbour recorded were higher than the maximum intra-sequence divergences for all species. It is concluded that DNA barcoding is a reliable technique for identification of agricultural pests, especially for immature stages when morphometric studies are ambiguous and will be helpful in the development of more effective pest management options for regulating pest species.

Four new species of the primitively segmented spider genus Qiongthela from Hainan island, China (Mesothelae, Liphistiidae)

Four species of the primitively segmented spider genus Qiongthela Xu & Kuntner, 2015 collected from Hainan Island, China are diagnosed and described as new to science based on their genital morphology: Q. bawangsp. n. (♀), Q. jianfengsp. n. (♂♀), Q. yinisp. n. (♀), Q. wuzhisp. n. (♂♀). Together with the type species of Qiongthela, Q. baishensis Xu, 2015, five species are found and described from Hainan, China, and seven species are now known in the genus.

DNA barcoding and traditional taxonomy: an integrated approach for biodiversity conservation

Biological diversity is depleting at an alarming rate. Additionally, a vast amount of biodiversity still remains undiscovered. Taxonomy has been serving the purpose of describing, naming, and classifying species for more than 250 years. DNA taxonomy and barcoding have accelerated the rate of this process, thereby providing a tool for conservation practice. DNA barcoding and traditional taxonomy have their own inherent merits and demerits. The synergistic use of both methods, in the form of integrative taxonomy, has the potential to contribute to biodiversity conservation in a pragmatic timeframe and overcome their individual drawbacks. In this review, we discuss the basics of both these methods of biological identification (traditional taxonomy and DNA barcoding), the technical advances in integrative taxonomy, and future trends. We also present a comprehensive compilation of published examples of integrative taxonomy that refer to nine topics within biodiversity conservation. Morphological and molecular species limits were observed to be congruent in ∼41% of the 58 source studies. The majority of the studies highlighted the description of cryptic diversity through the use of molecular data, whereas research areas like endemism, biological invasion, and threatened species were less discussed in the literature.

Rapid dissemination of taxonomic discoveries based on DNA barcoding and morphology

The taxonomic impediment is characterized by dwindling classical taxonomic expertise, and slow pace of revisionary work, thus more rapid taxonomic assessments are needed. Here we pair rapid DNA barcoding methods with swift assessment of morphology in an effort to gauge diversity, establish species limits, and rapidly disseminate taxonomic information prior to completion of formal taxonomic revisions. We focus on a poorly studied, but diverse spider genus, Pseudopoda, from East Asia. We augmented the standard barcoding locus (COI) with nuclear DNA sequence data (ITS2) and analyzed congruence among datasets and species delimitation methods for a total of 572 individuals representing 23 described species and many potentially new species. Our results suggest that a combination of CO1 + ITS2 fragments identify and diagnose species better than the mitochondrial barcodes alone, and that certain tree based methods yield considerably higher diversity estimates than the distance-based approaches and morphology. Combined, through an extensive field survey, we detect a twofold increase in species diversity in the surveyed area, at 42–45, with most species representing short range endemics. Our study demonstrates the power of biodiversity assessments and swift dissemination of taxonomic data through rapid inventory, and through a combination of morphological and multi-locus DNA barcoding diagnoses of diverse arthropod lineages.

Use of mitochondrial COI gene for the identification of family Salticidae and Lycosidae of spiders

In recent years, DNA barcoding has become quite popular for molecular identification of species because it is simple, quick and an affordable method. Present study was conducted to identify spiders of most abundant families, i.e. Salticidae and Lycosidae from citrus orchards in Sargodha district using DNA barcoding. A total of 160 specimens were subjected to DNA barcoding but, sequences up to 600 bp were recovered for 156 specimens. This molecular approach proved helpful to assign the exact taxon to those specimens which were misidentified through morphological characters in the study. We were succeeded to discriminate six species of Lycosidae and nine species of Salticidae through DNA barcoding. Results revealed the presence of clear barcode gap (discontinuity in intra- and inter-specific divergences) for members of both families. Furthermore, the maximum intra-specific divergence was less than NN (nearest neighbour) distance for all species. This suggested the reliability of DNA barcoding for spider's identification up to species level. We got 98% success in our study. It is concluded from present study that DNA barcoding is more reliable tool especially for immature spiders, when morphological characters are ambiguous.

Towards a DNA Barcode Reference Database for Spiders and Harvestmen of Germany

As part of the German Barcode of Life campaign, over 3500 arachnid specimens have been collected and analyzed: ca. 3300 Araneae and 200 Opiliones, belonging to almost 600 species (median: 4 individuals/species). This covers about 60% of the spider fauna and more than 70% of the harvestmen fauna recorded for Germany. The overwhelming majority of species could be readily identified through DNA barcoding: median distances between closest species lay around 9% in spiders and 13% in harvestmen, while in 95% of the cases, intraspecific distances were below 2.5% and 8% respectively, with intraspecific medians at 0.3% and 0.2%. However, almost 20 spider species, most notably in the family Lycosidae, could not be separated through DNA barcoding (although many of them present discrete morphological differences). Conspicuously high interspecific distances were found in even more cases, hinting at cryptic species in some instances. A new program is presented: DiStats calculates the statistics needed to meet DNA barcode release criteria. Furthermore, new generic COI primers useful for a wide range of taxa (also other than arachnids) are introduced.

DNA barcode data accurately assign higher spider taxa

The use of unique DNA sequences as a method for taxonomic identification is no longer fundamentally controversial, even though debate continues on the best markers, methods, and technology to use. Although both existing databanks such as GenBank and BOLD, as well as reference taxonomies, are imperfect, in best case scenarios "barcodes" (whether single or multiple, organelle or nuclear, loci) clearly are an increasingly fast and inexpensive method of identification, especially as compared to manual identification of unknowns by increasingly rare expert taxonomists. Because most species on Earth are undescribed, a complete reference database at the species level is impractical in the near term. The question therefore arises whether unidentified species can, using DNA barcodes, be accurately assigned to more inclusive groups such as genera and families-taxonomic ranks of putatively monophyletic groups for which the global inventory is more complete and stable. We used a carefully chosen test library of CO1 sequences from 49 families, 313 genera, and 816 species of spiders to assess the accuracy of genus and family-level assignment. We used BLAST queries of each sequence against the entire library and got the top ten hits. The percent sequence identity was reported from these hits (PIdent, range 75-100%). Accurate assignment of higher taxa (PIdent above which errors totaled less than 5%) occurred for genera at PIdent values >95 and families at PIdent values ≥ 91, suggesting these as heuristic thresholds for accurate generic and familial identifications in spiders. Accuracy of identification increases with numbers of species/genus and genera/family in the library; above five genera per family and fifteen species per genus all higher taxon assignments were correct. We propose that using percent sequence identity between conventional barcode sequences may be a feasible and reasonably accurate method to identify animals to family/genus. However, the quality of the underlying database impacts accuracy of results; many outliers in our dataset could be attributed to taxonomic and/or sequencing errors in BOLD and GenBank. It seems that an accurate and complete reference library of families and genera of life could provide accurate higher level taxonomic identifications cheaply and accessibly, within years rather than decades.