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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. Taxonomic identification of spider species from morphological structures has limitations in cases of closely related species or intraspecific variability. We investigate the utility of genetic barcoding with the mitochondrial marker cytochrome c oxidase I (COI) in ghost spiders of the subfamily Amaurobioidinae. Most discrepancies between DNA barcoding and morphological identification are explained by low geographic sampling or by geographically structured lineages. In addition, we show that the marker COI is phylogenetically informative for deeper nodes in the tree. (Image credit: Martín Ramírez.) [ABSTRACT FROM AUTHOR]

Australian salt lakes contain a diverse range of endemic invertebrates. The brine shrimp Parartemia is among the most speciose and salt-tolerant of these invertebrates. The morphotaxonomy of Parartemia is well established but there has only been limited molecular assessment of the phylogenetic relationships and boundaries of the morphospecies. We used multiple genetic markers (nuclear 28S and mitochondrial 16S and COI) and tree-building methods (Bayesian inference and maximum likelihood) to investigate the phylogeny of Parartemia. We also used species delimitation methods to test the validity of morphological species designations. The data set included all but 2 of the 18 described Parartemia morphospecies, collected from a total of 93 sites from across southern Australia plus some sequences from GenBank. The results identified large amounts of molecular divergence (e.g. COI P- values of up to 25.23%), some groups of closely related species (which also usually shared some morphological similarities) and some distinctive species, although the relationships among divergent lineages were generally not well resolved. The most conservative set of results from the species delimitation analyses suggests that the morphotaxonomy is largely accurate, although many morphospecies comprised divergent genetic lineages separated by COI P- values of up to 17.02%. Two putative new morphospecies, three cryptic species and one synonymy were identified. Our findings improve the knowledge of Parartemia taxonomy and will facilitate the development of future studies and conservation of this taxon. The brine shrimp Parartemia is a diverse, salt-tolerant genus found in Australian salt lakes. Its current taxonomy is mainly based on morphological data. We used molecular data to investigate the number and relationships of Parartemia species and found two new morphospecies and three cryptic species. Although most species were valid, molecular divergence among and within some species was substantial. Our results confirm the species richness of the genus and our updated species list will aid in targeted conservation efforts. (Image credit: Md Aminul Islam.) [ABSTRACT FROM AUTHOR]

Munidopsid squat lobsters are among the most abundant decapods at abyssal depths and the most diverse squat lobster group in the East Pacific region. During recent cruises along the East Pacific, many deep-sea squat lobsters were collected. Among these, we described five new munidopsid species supported both by morphological characters and molecular phylogenetics: Munidopsis girguisi sp. nov., M. nautilus sp. nov., M. testuda sp. nov., M. cortesi sp. nov. and M. hendrickxi sp. nov. We also report new records of several Munidopsis species across the East Pacific that increase the species distribution ranges. Here, we reconstructed the phylogenetic relationships of the East Pacific species in relation to other Galatheoidea using one nuclear and two mitochondrial gene fragment(s); we also performed single locus species delimitation analyses to explore the species status of various East Pacific munidopsid taxa. The new taxa were photographed, illustrated and imaged with micro-computed tomography. The phylogenetic results show that: (1) Janetogalathea californiensis, previously included in the family Galatheidae, nests within Munidopsidae; (2) the phylogenetic position of Phylladiorhynchus and Coralliogalathea as belonging in Galatheidae is not supported; and (3) Munidopsis is paraphyletic, agreeing with recent systematic hypotheses. Short genetic distances and species delimitation analyses suggested that a clade mostly constituted by abyssal species might include fewer species than currently considered, as species show a wider geographic range than previously considered, conforming with traditional hypotheses of cosmopolitanisms in abyssal species. ZooBank: urn:lsid:zoobank.org:pub:CED9EB18-7061-47A7-B2FF-7F1DAFCC7B12.

Mastigusa is a genus of small palearctic spiders that has recently been moved to the family Cybaeidae after the first inclusion of the genus in a phylogenetic matrix. Three species are currently recognised: M. arietina , M. lucifuga and M. macrophthalma. The status and delimitation, though, has always been problematic due to inconsistency in the characters used to discriminate between these, leading to great confusion in identity and distribution. We present a detailed morphological redescription of the genus and a taxonomic revision of the included species by the combined use of morphological data and molecular species-delimitation techniques based on the mitochondrial COI gene. The status of the three currently described species has been reevaluated and Mastigusa diversa was revalidated based on material from the Iberian Peninsula, North Africa and the United Kingdom. The distribution of Mastigusa species is updated based on novel taxonomic considerations, and comments on the natural history and ecological differences observed in the species are provided. ZooBank: urn:lsid:zoobank.org:pub:AAD3FAED-440F-4295-B458-455B1D913F81 The debatable identity and delimitation of spider species of Mastigusa have confused the taxonomic status and distribution. Broad sampling, and morphological and molecular techniques were used to revise the species' statuses. Three Mastigusa species were recircumscribed and redescribed, and the distributions updated. Based on a reexamination of type material, Mastigusa diversa O. Pichard-Cambridge, 1893 is revalidated. Mastigusa shows strong ecological plasticity, and understanding the species delimitations and distributions will unravel drivers of extreme lifestyles such as myrmecophily and cave-dwelling. (Image credit: F. Castellucci.) [ABSTRACT FROM AUTHOR]

A recent molecular phylogenetic and biogeographic study on the krill genus Hansarsia revealed undescribed cryptic diversity in the Atlantic. Each of four species analysed encompassed robust molecular clades that were linked to dimorphic males in H. microps , H. atlantica and H. tenella. We tested the robustness and divergence of the observed clades using an integrative approach including (1) three independent species delimitation methods for the mitochondrial COI gene (ASAP, GMYC, bPTP), (2) variability of two nuclear genes (H3 and ITS1) and (3) morphological analysis (MDS and PCA) with a dataset of 22 characters scored for 131 specimens. Both molecular and morphological analyses resulted in at least six distinct clades within the Atlantic Hansarsia. The strongest divergence was revealed between the two clades of H. tenella , one of which we diagnosed as a new species. Two clades of H. megalops also showed significant divergence but in the absence of males, we were reluctant to designate new species. Different clades linked to male forms in H. microps and H. atlantica are suggested as an incipient species. We also hypothesise an unusual trend in the evolution of euphausiids, in which visual recognition enhances tactile interaction during mating. Our results show that analyses of ostensibly well studied groups may yet yield taxonomic surprises. ZooBank: urn:lsid:zoobank.org:pub:AE045636-50EF-450A-B9B3-9231E8B91522 We characterise the biodiversity of the taxonomically entangled krill genus Hansarsia in the deep Atlantic by applying an integrative approach. Molecular and morphological analyses suggest at least six species of Hansarsia instead of the currently recognised four. We describe one new species and wait for males to describe the second one. The results confirm ongoing diversification of the Atlantic krill and show an unusual trend in the evolution of euphausiids, in which visual recognition enhances tactile interaction during mating. (Image credit: D. Kulagin.) [ABSTRACT FROM AUTHOR]

The pachychilid genus Brotia H. Adams, 1866, distributed across South and South-East Asia, comprises 46 currently accepted species. Although Brotia has recently been revised, the systematic treatment of the Indian species requires further scrutiny. This study aims to resolve the phylogenetic relationships between Brotia species from north-east India and estimate the divergence using two mitochondrial markers, cytochrome c oxidase subunit I (COI) and 16S ribosomal RNA (16S). Species delimitation analyses have revealed six to nine distinct species in north-east India instead of the single currently known species. We confirm the monophyly of Brotia from the entire distributional range in South and South-East Asia and show that all Indian species form a single clade nested within the South-East Asian radiation. We conclude that Brotia has a South-East Asian origin, with two independent dispersals into India since the early Eocene and through the Oligocene, eventually splitting from ancestors during the late Cretaceous. Further integrative taxonomic research is needed to resolve the taxonomic status of the candidate species delineated herein and reveal the exact number of species in north-east India. This is the first phylogenetic analysis of Brotia from India, significantly improving our understanding of Indian freshwater gastropod fauna. [ABSTRACT FROM AUTHOR]

Snorkel snails (genus Rhiostoma) are widely distributed in Indo-China and on the Malay Peninsula. The shell morphology is traditionally used for species identification yet in Thailand, the common snorkel snail, Rhiostoma housei , shows considerable variation in shell morphology within and between populations. Therefore species identifications and delimitations are difficult. We used two mitochondrial DNA fragments (COI and 16S rRNA) and morphological characters to delimit species and infer phylogenetic relationships of Rhiostoma housei s.l. from eight localities in Thailand, representing potential cryptic species suggested by earlier allozyme and karyological data. Results revealed four distinct clades from different geographic areas in Thailand. Species delimitation analyses confirmed the clades as four separate species and a geometric morphometric analysis demonstrated subtle but consistent conchological differences between the four clades. The high COI sequence divergences among the four clades (mean: 14.8%; range: 10.3–16.5%) further supported the species level recognition. As a consequence, three new species are described from Thailand: R. khoratense , sp. nov., R. nakwangense , sp. nov. and R. phunangense , sp. nov. ZooBank: urn:lsid:zoobank.org:pub:EE534749-9346-4972-BF2E-3B5D0EB8AED8 Snorkel snails of the genus Rhiostoma have considerable variation in shell morphology. We used two mtDNA fragments, morphological characters and shell geometric morphometrics to infer phylogenetic relationships. Results revealed four distinct clades and four separate species under the name R. housei. [ABSTRACT FROM AUTHOR]

The peculiar family Murrayidae, comprising the genera Murrayon, Dactylobiotus and Macroversum , contains relatively rare species living in hydrophilic and freshwater habitats on all continents, and contains two of the six exclusively freshwater tardigrade genera. This family probably represents an example of the evolution and persistence of an asexual lineage that differentiated into several taxa without sexual reproduction. Analyses of nuclear and mitochondrial genes (18S , 28S , ITS2 and cox1), and the increase of five taxa to the phylogenetic analyses of Murrayidae led us to infer that Murrayon is polyphyletic, being composed of two 'species groups' that also find morphological supports: the ' dianeae group' characterised by peculiar egg processes (rod-shaped and covered with a cuticular layer), animals with large, evident epicuticular pillars and small claws; and the ' pullari group' characterised by conical egg processes, animals with very small epicuticular pillars, and proportionally larger and longer claws. This latter group is a sister group to Dactylobiotus. Murrayon hastatus is the only species within the genus that has an uncertain position with eggs of the ' dianeae group' and animals of the ' pullari group'. We propose the erection of Paramurrayon gen. nov. (for the ' dianeae group' of species), the emendation of Murrayon , and new taxonomic keys for both genera. Possible scenarios of the evolution of taxa within Murrayidae are hypothesised based on synapomorphic characters. Paramurrayon meieri sp. nov. from Norway is described with an integrative approach. Photographs of type material of Murrayon stellatus, Murrayon nocentiniae, Murrayon ovoglabellus and Macroversum mirum are shown for the first time, together with descriptions of new characters. Murrayon hibernicus is considered as nomen dubium and Murrayon hyperoncus is transferred to Macrobiotus pending further analyses. [ABSTRACT FROM AUTHOR]

The sponge genus Oscarella is very important for the understanding of the early evolution of Metazoa, but the identification of its species is particularly difficult due to the absence of a skeleton and high polymorphism, leading to an underestimate of its diversity. The discovery of nine distinct morphotypes of Oscarella co-existing in cryptic habitats in south-east Brazil represents a taxonomic puzzle that requires an integrative taxonomic approach for species delimitation. Here we combined genetic (cox-1 and cob genes), morphological, anatomical, cytological, microbiological, reproductive and ecological datasets to delimit and describe three new species of Oscarella , one of which is highly polymorphic. Oscarella aurantia , sp. nov. is orange, microlobate, with metachromatic vacuolar cells, granular cells, and microgranular cells. Oscarella carollineae , sp. nov. is intertidal, cream or red, microlobate, with granulo-vacuolar cells, dense globular cells, and granular cells. Oscarella ruthae , sp. nov. is highly polymorphic, with tubular or papillate lobes; colour violet, pink, purple, red, orange or cream, often with shades of cream or green at the base; abundant clusters of vacuolar cells type 1, and rare vacuolar cells type 2 and microgranular cells. No single character was sufficient for species delimitation due to high intraspecific variation. Integration of multiple datasets was essential to delimit species of Oscarella and would also be helpful for the taxonomy of other polymorphic sponges. ZooBank LSID: urn:lsid:zoobank.org:pub:0CA34949-1C29-46E8-9AB3-E89F73909E37 The species of the sponge genus Oscarella are difficult to define because they have no skeleton, and some species may be highly variable. We found nine types of Oscarella co-existing in south-east Brazil and we combined genetic, morphological, anatomical, cytological, microbiological, reproductive and ecological information to determine how many species are there. As a result, we described three new species of Oscarella , of which one is highly variable. [ABSTRACT FROM AUTHOR]

Extensive sampling around Martinique during the Muséum National d'Histoire Naturelle 'Madibenthos' expedition in 2016 resulted in a collection of hundreds of alpheid shrimps, of which 21 distinct species of Synalpheus Spence Bate, 1888 are studied herein. Combining results of a morphological analysis, a phylogenetic tree (combined 16S and COI) and species delimitation analyses (ABGD and PTP) indicates three species as new to science. These species are S. chaki sp. nov., S. corbariae sp. nov., and S. macdonaldi sp. nov. The first two new species belong to the S. rathbunae Coutière, 1909 species group, whereas the third new species broadly groups with the S. gambarelloides group. Additionally, 13 new country records of Synalpheus are reported for Martinique. [ABSTRACT FROM AUTHOR]

The Antarctic marine environment, although rich in life, is predicted to experience rapid and significant effects from climate change. Despite a revolution in the approaches used to document biodiversity, less than one percent of Antarctic marine invertebrates are represented by DNA barcodes and we are at risk of losing biodiversity before discovery. The ease of sequencing mitochondrial DNA barcodes has promoted this relatively 'universal' species identification system across most metazoan phyla and barcode datasets are currently readily used for exploring questions of species-level taxonomy. Here we present the most well-sampled phylogeny of the direct-developing, Southern Ocean nudibranch mollusc, Doris kerguelenensis to date. This study sampled over 1000 new Doris kerguelenensis specimens spanning the Southern Ocean and sequenced the mitochondrial COI gene. Results of a maximum likelihood phylogeny and multiple subsequent species delimitation analyses identified 27 new species in this complex (now 59 in total). Using rarefaction techniques, we infer more species are yet to be discovered. Some species were only collected from southern South America or the sub-Antarctic islands, while at least four species were found spanning the Polar Front. This is contrary to dispersal predictions for species without a larval stage such as Doris kerguelenensis. Our work demonstrates the value of increasing geographic scope in sampling and highlights what could be lost given the current global biodiversity crisis. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Morphological variability within Cassiopea is well documented and has led to inaccuracies in the establishment of species boundaries in this taxon. Cassiopea medusae specimens from the Western Pacific (Japan and the Philippines) were analysed using multiple lines of complementary evidence, including types of cnidae, macro-morphology and molecular data. These observations lead to the recognition of two distinct species: Cassiopea mayeri , sp. nov. and a previously synonymised variety now raised to species level (Cassiopea culionensis , stat. nov.). These species can be distinguished from each other using morphological features. Herein, sexually dimorphic traits are included for the first time in the descriptions of Cassiopea species. Nematocyst types not previously observed in the genus are also reported. Molecular analyses, based on individual and combined markers (16S + cytochrome c oxidase I, COI), also support two distinct species; they are not sister taxa, and both are nested together within a clade of other Cassiopea members from the Australian and Indo-Pacific regions. Species richness is underestimated in the Western Pacific region, and integrative approaches are helpful to reveal and describe species. The systematics of Cassiopea is far from completely understood, but the present study represents an important further step. http://www.zoobank.org/References/B1A66787-009D-4465-954A-412C6878FCB4. Integration of multiple lines of evidence for the study of jellyfish diversity has shown that it is more species-rich than traditionally thought. Using an integrative approach, we identified specimens of Cassiopea medusae from the Philippines and Japan. They belong to two species: one new and one previously recognised as a variety. Our results support the hypothesis that the species richness of jellyfish is underestimated, and this study can serve as a reference to uncover hidden diversity of Cassiopea and other allied taxa. [ABSTRACT FROM AUTHOR]

The deep sea of temperate south-eastern Australia appears to be a 'hotspot' for diversity and endemism of conoidean neogastropods of the family Raphitomidae. Following a series of expeditions in the region, a considerable amount of relevant DNA-suitable material has become available. A molecular phylogeny based on this material has facilitated the identification of diagnostic morphological characters, allowing the circumscription of monophyletic genera and the introduction of several new genus-level taxa. Both named and new genera are presently being investigated through integrative taxonomy, with the discovery of a significant number of undescribed species. As part of this ongoing investigation, our study focuses on the genera Famelica Bouchet & Warén, 1980, Glaciotomella Criscione, Hallan, Fedosov & Puillandre, 2020 and Rimosodaphnella Cossmann, 1914. We subjected a comprehensive mitochondrial DNA dataset of representative deep-sea raphitomids to the species delimitation methods ABGD and ASAP that recognised 18 and 15 primary species hypotheses (PSHs) respectively. Following additional evaluation of shell and radular features, and examination of geographic and bathymetric ranges, nine of these PSHs were converted to secondary species hypotheses (SSHs). Four SSHs (two in Famelica and two in Rimosodaphnella) were recognised as new, and formal descriptions are provided herein. Despite the importance of geographical distribution for understanding the evolution and diversity of deep-sea snails, this remains poorly known. We combine genetic, shell, anatomical and distribution data from three genera to identify four new species from Australia and beyond that we describe here, with an emphasis on rare or endemic species. Our findings suggest that radula and protoconch features can help interpret genus-level relationships. We discuss the role of the environment in shaping the snails' evolution. [ABSTRACT FROM AUTHOR]

Thouarella Gray, 1870, is one of the most speciose genera among gorgonians of the family Primnoidae (Cnidaria : Octocorallia : Anthozoa), being remarkably diverse in the Antarctic and sub-Antarctic seafloor. However, their diversity in the Southern Ocean is likely underestimated. Phylogenetic analyses of mitochondrial and nuclear DNA markers were integrated with species delimitation approaches as well as morphological colonial and polyps features and skeletal SEM examinations to describe and illustrate three new species within Thouarella , from the Weddell Sea, Southern Ocean: T. amundseni sp. nov., T. dolichoespinosa sp. nov. and T. pseudoislai sp. nov. Our species delimitation results suggest, for the first time, the potential presence of Antarctic and sub-Antarctic cryptic species of primnoids, based on the likely presence of sibling species within T. undulata and T. crenelata. With the three new species here described, the global diversity of Thouarella has increased to 41 species, 15 of which are endemic to the Antarctic and sub-Antarctic waters. Consequently, our results provide new steps for uncovering the shelf benthonic macrofauna's hidden diversity in the Southern Ocean. Finally, we recommend using an integrative taxonomic framework in this group of organisms and species delimitation approaches because the distinctions between some Thouarella species based only on a superficial examination of their macro- and micromorphological features is, in many cases, limited. The family Primnoidae includes common and diverse gorgonian lineages in the Antarctic benthic communities, where they play an essential role in structuring these habitats. However, taxonomic identifications of primnoids to the species level can be challenging. The complementary use of molecular and morphological data of dozens of primnoid colonies recovered from the Weddell Sea has allowed us to recognise new species within the primnoid genus Thouarella , providing further steps to uncover the shelf benthonic macrofauna's hidden diversity in the Southern Ocean. [ABSTRACT FROM AUTHOR]

The routine use of DNA sequencing techniques and phylogenetic analysis has resulted in the discovery of many cryptic species, especially in the oceans. The common, globally introduced species Styela canopus is suspected to be a complex of cryptic species because of its widespread distribution and variable external morphology. We tested this possibility using COI and ANT marker sequences to uncover the phylogenetic relationship among 19 populations, and to examine genetic variability as well as gene flow. We obtained 271 COI and 67 ANT sequences and found surprising diversity among the 19 populations (COI : π = 0.18, hd = 0.99; ANT : π = 0.13, hd = 0.95). Corresponding topologies were found using Bayesian inference and maximum likelihood for both simple locus (COI) and multilocus (COI + ANT) analyses and so the clades received strong support. We used simple (ABGD, bPTP, GMYC) and multiple (BSD) locus methods to delimit species. The simple locus methods indicated that the current Styela canopus comprises at least 15 species. The BSD method for concatenated data supported 7 of the 15 species. We suggest that S. canopus should be treated as the Styela canopus complex. The large number of cryptic species found, often with more than one clade found in sympatry, creates opportunities for better understanding reproductive isolation, hybridisation or speciation. As several lineages have already been introduced widely around the world, we must quickly understand their diversity and invasive abilities. [ABSTRACT FROM AUTHOR]

The Cyphophthalmi genus Troglosiro (the only genus of the family Troglosironidae) is endemic to New Caledonia, representing one of the oldest lineages of this emerged part of Zealandia. Its species are short-range endemics, many known from single localities. Here we examined the phylogenetic relationships of Troglosironidae using standard Sanger-sequenced markers (nuclear 18S rRNA, 28S rRNA, and mitochondrial 16S rRNA and cytochrome c oxidase subunit I) and a combination of phylogenetic methods, including parsimony under Direct Optimization and maximum likelihood with static homology. We also applied a diversity of species delimitation methods, including distance-based, topology-based and unsupervised machine learning to evaluate previous species designations. Finally, we used a combination of genetic and morphological information to describe four new species - T. dogny sp. nov., T. pin sp. nov., T. pseudojuberthiei sp. nov. and T. sharmai sp. nov. - and discuss them in the broader context of the phylogeny and biogeographic history of the family. A key to the species of Troglosiro is also provided. [ABSTRACT FROM AUTHOR]

Accurate species delimitation is essential for the study of biodiversity, but morphological approaches often provide a limited ability to connect different life stages, sexes or other phenotypic variants in eriophyoid mites because many species possess two phenotypically distinct forms: protogynes and deutogynes. In this study, we analysed the morphological variation in 26 populations of the eriophyoid mite, Epitrimerus sabinae Xue & Hong, 2005 s.l., from sites across its entire known distribution and revealed three morphotypes (LNS: large, normal palp seta d; MBS: medium, bifurcated palp seta d; SBS: small, bifurcated palp seta d) distinguished by body size and structure of dorsal pedipalp genual seta. Five lines of evidence (morphometrics, DNA-based species delimitation, phylogenetics, haplotype network, mitochondrial genome architecture) indicated that the MBS and SBS groups were very distinct from LNS (E. sabinae s.s.). In fact, the MBS and SBS morphotypes are properly placed in the genus Leipothrix with the MBS lineage representing the protogyne of L. juniperensis, sp. nov., whereas the SBS lineage is its deutogyne. By expanding the approaches used to link protogynes and deutogynes of eriophyoid mites, this study provides a way to accelerate the delineation of species boundaries in this important group of plant pests. [ABSTRACT FROM AUTHOR]

Integrative taxonomy assesses the congruence between different lines of evidence for delimiting species, such as morphological, molecular or ecological data. Herein molecular phylogenetics is used to test monophyly and determine the phylogenetic position of the Old World tropical centipede genus Ethmostigmus Pocock, 1898, and to define species boundaries for Ethmostigmus in peninsular India. A phylogeny of the family Scolopendridae based on DNA sequence data for three markers from 427 specimens sampling in all major lineages (144 individuals generated in this study) recovers Ethmostigmus as a monophyletic group, but relationships among the genera in its subfamily Otostigminae are poorly supported. Two species delimitation methods for DNA sequence data and phylogeny are integrated with morphology and geographic data to propose a well-supported species hypothesis for Ethmostigmus on the peninsular Indian plate. Five species of Ethmostigmus are recognised in peninsular India, of which E. coonooranus Chamberlin, 1920 and three new species, namely, E. agasthyamalaiensis , sp. nov., E. sahyadrensis , sp. nov. and E. praveeni , sp. nov., occur in the Western Ghats, a biodiversity hotspot. The lesser-known Eastern Ghats harbour one species, E. tristis (Meinert, 1886), which has been nearly unreported for 130 years. This study highlights the value of an integrative approach to systematics, especially in underexplored, high biodiversity regions and where morphological variation is limited among closely related species. Tropical forests of Asia are relatively unexplored for terrestrial arthropods. In this study, we use DNA, morphology and distribution data for a group of scolopendrid centipedes to revise its systematics, and describe three new species from a global biodiversity hotspot, the Western Ghats, India. We also rediscovered a species after 130 years from the lesser-known Eastern Ghats. [ABSTRACT FROM AUTHOR]

An integrative approach to investigate the species-level diversity in Oxynoe (Mollusca, Heterobranchia, Sacogloßa) revealed the existence of 11 distinct taxa. Oxynoe viridis (Pease, 1861) and Oxynoe antillarum M'rch, 1863 are redescribed; Oxynoe natalensis E. A. Smith, 1903 and Oxynoe azuropunctata Jensen, 1980 are regarded as valid. Species originally described from empty shells are regarded as nomina dubia. Seven new species are described, four from the tropical Indo-West Pacific: Oxynoe kylei, sp. nov., Oxynoe neridae, sp. nov., Oxynoe jordani, sp. nov. and Oxynoe jacksoni, sp. nov.; and two from the tropical Atlantic: Oxynoe struthioe, sp. nov. and Oxynoe ilani, sp. nov. The name Oxynoe panamensis Pilsbry & Olßon, 1943 has been applied to eastern Pacific specimens, but was introduced based on material collected from the Caribbean; therefore, the new name Oxynoe aliciae, sp. nov. is introduced for eastern Pacific specimens. Species are delineated using molecular and morphological traits, as well as algal host and reproductive biology. Results from morphological comparisons are concordant with molecular and integrative species delimitation analyses, providing robust evidence for species hypotheses. As Oxynoe is one of the few groups specialised to feed on the green algal genus Caulerpa, which includes highly invasive species, clarifying the taxonomy of Oxynoe may inform efforts to predict community response to disruptive algal invasions. [ABSTRACT FROM AUTHOR]

The Pleurobemini (Bivalvia: Unionida) represent approximately one-third of freshwater mussel diversity in North America. Species identification within this group is challenging due to morphological convergence and phenotypic plasticity. Accurate species identification, including characterisation of currently unrecognised taxa, is required to develop effective conservation strategies because many species in the group are imperiled. We examined 575 cox1 sequences from 110 currently recognised species (including 13 Fusconaia and 21 Pleurobema species) to understand phylogenetic relationships among pleurobemine species (mainly Fusconaia and Pleurobema) and to delineate species boundaries. The results of phylogenetic analyses showed no geographic structure within widespread species and illustrated a close relationship between Elliptio lanceolata and Parvaspina collina. Constraint tests supported monophyly of the genera Fusconaia and Pleurobema, including the subgenus P. (Sintoxia). Furthermore, results revealed multiple conspecifics, including P. hanleyianum and P. troschelianum, P. chattanoogaense and P. decisum, P. clava and P. oviforme, P. rubrum and P. sintoxia, F. askewi and F. lananensis, and F. cerina and F. flava. Species delimitation analyses identified three currently unrecognised taxa (two in Fusconaia and one in Pleurobema). Further investigation using additional genetic markers and other lines of evidence (e.g. morphology, life history, ecology) are necessary before any taxonomic changes are formalised. [ABSTRACT FROM AUTHOR]

Marine oligochaetous clitellates are poorly investigated in the South Atlantic Ocean, especially along the east coast of South America. Closely related species are often difficult to distinguish based on morphology. The lack of specialists and modern identification guides have been pointed out as the main reasons for the scarcity of studies in the South Atlantic Ocean as a whole. To increase the knowledge of this group in the South Atlantic, the genetic diversity of a sample of marine oligochaetous clitellates from Brazil, South Africa and Antarctica was assessed by the Automatic Barcode Gap Discovery (ABGD) and the generalised mixed Yule coalescent (GMYC) approaches. In total, 80 cytochrome c oxidase subunit I (COI) sequences were obtained, each with ~658 bp, estimated to represent 32 distinct putative species. ABGD established a barcoding gap between 3% and 14% divergence for uncorrected p-distances and the estimates of GMYC were largely concordant. All the clusters or putative species were genetically associated with previously known species or genera. This study thus confirms the adequacy of the COI barcoding approach combined with a genetic divergence threshold at the order of 10% for marine oligochaetous clitellates. [ABSTRACT FROM AUTHOR]

The number of subterranean taxa discovered in the north of Western Australia has substantially increased due to the requirements for environmental surveys related to mining development. Challenges in estimating subterranean biodiversity and distributions are related to lack of knowledge of taxa with convergent morphological characters in a largely unobservable ecosystem setting. An integrated approach is warranted to understand such complexity. Bathynellidae occur in most Australian aquifers, but only one species has been described so far, and the group lacks a reliable taxonomic framework. A new genus and one new species from the Pilbara region of Western Australia, Pilbaranella ethelensis, gen. et sp. nov., is described using both morphological and molecular data. Three additional species of Pilbaranella are defined through mitochondrial and nuclear genes, using Automatic Barcode Gap Discovery and Poisson Tree Processes species delimitation methods. A comparison of morphology and 18S rRNA sequences between Pilbaranella, gen. nov. and known lineages provides the evidentiary basis for the decision to establish a new genus. This study provides a morphological and molecular framework to work with Bathynellidae, especially in Australia where a highly diverse fauna remains still undescribed. [ABSTRACT FROM AUTHOR]

Species-level taxonomy and phylogeny of two genera of South-East (SE) Asian pachybolid millipedes are analysed with a combination of morphological characters and DNA sequences (two mitochondrial gene fragments: COI and 16S rRNA). Strong support is found for the genera Litostrophus Chamberlin, 1921 and Atopochetus Attems, 1953 and for a clade consisting of Litostrophus + Atopochetus. Four species of Litostrophus are recognised and (re)described: L. segregatus Chamberlin, 1921 (type species of the genus), L. scaber (Verhoeff, 1938), comb. nov., L. chamaeleon, sp. nov. and L. saraburensis, sp. nov. The genus Tonkinbolus Verhoeff, 1938 (type species T. scaber Verhoeff, 1938) is synonymised under Litostrophus. Atopochetus (type species A. rubropunctatus Attems, 1953), hitherto considered a dubious synonym of Aulacobolus Pocock, 1903, is re-instated for several species until now placed in Tonkinbolus and seven new species. All in all, 10 species of Atopochetus are (re)described: A. dollfusii (Pocock, 1893) (= Aulacobolus rubropunctatus Attems, 1938, syn. nov.), A. moulmeinensis (Pocock, 1893), A. sumatranus (Carl, 1906) (= Trachelomegalus laciniatus Attems, 1937, syn. nov.), A. anaticeps, sp. nov., A. helix, sp. nov., A. setiferus, sp. nov., A. spinimargo, sp. nov., A. truncatus, sp. nov., A. uncinatus, sp. nov. and A. weseneri, sp. nov. Three species recently included in Tonkinbolus are left incertae sedis because they are based exclusively on female type specimens: Spirobolus capucinus Porat, 1896, S. caudulanus Karsch, 1881 and S. macrurus Pocock, 1893. The results of the DNA analysis (COI and 16S rRNA) are congruent with morphological (gonopodal) characters in terms of delimitation of species of Litostrophus and Atopochetus. This is the first DNA study of SE Asian Pachybolidae and as such it provides a basis for further evolutionary and biogeographic studies of SE Asian millipedes. [ABSTRACT FROM AUTHOR]

Integrative taxonomy, including molecular, morphological, distributional and biological data, is applied in a review of the taxonomy of the Australian species of the pest termite genus Coptotermes. The validity of the previously described species is discussed, and two new species, Coptotermes nanus, sp. nov. and Coptotermes cooloola, sp. nov., are described from the Kimberley region of Western Australia and south-east Queensland respectively. Their delimitation is based on morphological and distributional data, and the results of generalised mixed Yule-coalescent analysis of mitochondrial DNA sequence data. Images of the external view of the two new species are provided, as well as a key, based on soldier characters, for all Australian species of Coptotermes. [ABSTRACT FROM AUTHOR]

Antarctica contains some of the most challenging environmental conditions on the planet due to freezing temperatures, prolonged winters and lack of liquid water. Whereas 99.7% of Antarctica is permanently covered by ice and snow, some coastal areas and mountain ridges have remained ice-free and are able to sustain populations of microinvertebrates. Tardigrades are one of the more dominant groups of microfauna in soil and limno-terrestrial habitats, but little is known of their diversity and distribution across Antarctica. Here, we examine tardigrades sampled from across an extensive region of continental Antarctica, and analyse and compare their partial mitochondrial cytochrome c oxidase subunit 1 (COI) gene sequences with those from the Antarctic Peninsula, maritime and sub-Antarctica, Tierra del Fuego and other worldwide locations in order to recognise operational taxonomic units (OTUs). From 439 new tardigrade COI sequences, we identified 98 unique haplotypes (85 from Antarctica) belonging to Acutuncus, Diphascon, Echiniscus, Macrobiotus, Milnesium and unidentified Parachela. Operational taxonomic units were delimited by Poisson tree processes and general mixed Yule coalescent methods, resulting in 58 and 55 putative species, respectively. Most tardigrades appear to be locally endemic (i.e. restricted to a single geographic region), but some (e.g. Acutuncus antarcticus (Richters, 1904)) are widespread across continental Antarctica. Our molecular results reveal: (i) greater diversity than has previously been appreciated with distinct OTUs that potentially represent undescribed species, and (ii) a lack of connectivity between most OTUs from continental Antarctica and those from other Antarctic geographical zones. [ABSTRACT FROM AUTHOR]

In Opiliones, one of the largest orders within the class Arachnida, with more than 6000 described species, sexual dimorphism can be widespread and exaggerated. This great variety of forms of gender-based dimorphism suggests that sexual selection may play an important role in the diversification of some lineages. It also impacts species identification, assignment of females to described species and biodiversity assessments. Here we use DNA-sequence-based species discovery methods (the Poisson Tree Processes model with Bayesian support values, bPTP, and the Generalized Mixed Yule-Coalescent approach, GMYC, accounting for phylogenetic uncertainty) to shed light on the morphological disparity displayed in several species of neopilionid harvestmen from New Zealand. Both species delimitation analyses recovered many clades that coincide with our prior assignment of morphospecies, based solely on males, and allowed us to assign females and juveniles to these species as well as to identify putative new species and to assign some unidentified species to genera. Several genetic species, particularly Forsteropsalis inconstans and Pantopsalis cheliceroides-listeri, showed complex morphological disparity in the size and shape of the male chelicerae, but also in the general size and coloration patterns of the males. The systematic implications of our results and a possible ecological explanation for the exaggerated traits are discussed. Following our findings, the following taxonomic action is taken: Forsteropsalis nigra is considered a junior synonym of F. inconstans (new synonymy). [ABSTRACT FROM AUTHOR]

Aoraki denticulata, a widespread mite harvestman endemic to the NW South Island of New Zealand, was postulated to constitute an old lineage with deep genetic history. Expanding on previous studies, we explored its genetic diversity and population structure, phylogeography and diversification patterns. We also examined the systematic implications of such a complex scenario through species delimitation analyses under coalescent-based and barcoding gap discovery methodologies. Our results depict the deep evolutionary history of the A. denticulata lineage, which shows high geographic structure and low genetic connectivity among modern populations. Aoraki denticulata is further subdivided into three lineages: a lineage presently inhabiting the northern region of the Southern Alps (and including the subspecies A. d. major), a second lineage in the north-eastern part of the sampled land, and a third one occupying the south-eastern localities. When using species delimitation methods based on coalescence approaches, large numbers of cryptic species were estimated. Based on morphological and biological evidence, we thus argue that these methods may overestimate species in cases in which genetic divergence is unusually large and discuss the systematic implications of our findings. [ABSTRACT FROM AUTHOR]