Three species of the genus Asterina are known to inhabit the Mediterranean Sea and the north-eastern Atlantic Ocean: Asterina gibbosa (Pennant, 1777), A. pancerii (Gasco, 1870) and A. phylactica Emson & Crump, 1979. Differentiation of these species has primarily been based only on subtle characters (some highly debatable), such as colour or size. Therefore, this study aimed to review the morphological data characterising members of the genus, to incorporate new characters that may clarify morphological analyses and to couple morphological data with molecular evidence of differentiation based on the analysis of partial sequences of the cytochrome c oxidase subunit I (COI) and 18S rDNA (18S) genes and two anonymous nuclear loci (AgX2 and AgX5). The different lineages and cryptic species identified from the molecular analysis were then morphologically characterised, which was challenging given the limited number of diagnostic characters. Two of the five monophyletic lineages obtained molecularly (COI divergence >4%), further supported by differences in morphological characters and reproductive behaviour, are proposed as new species: Asterina martinbarriosi, sp. nov. from the Canary Islands, Spain (eastern central Atlantic Ocean) and Asterina vicentae, sp. nov. from Tarragona, north-eastern Spain (western Mediterranean Sea).

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.

Records of cryptic species have continued to emerge in the scientific literature, often revealed by the use of molecular phylogenetic analyses in an integrative taxonomic approach. This study addresses a group of four striped flatworms from the genus Pasipha Ogren & Kawakatsu, showing a pale median stripe on a dark dorsal surface. Based on morphological and molecular analyses from the cytochrome c oxidase subunit I gene (COI), we establish that we are dealing with sibling species that are closely related to P. brevilineata Leal-Zanchet, Rossi & Alvarenga, 2012, a recently described species with a similar colour pattern. Thus, we describe three of the studied flatworms as new species and propose one new unconfirmed candidate species based on molecular data. In addition, sequence analysis revealed 40 nucleotide autapomorphies supporting the species studied herein. Considering anatomical and histological features, the three new species are differentiated from their congeners mainly by details of the copulatory apparatus, such as the occurrence of an epithelium of pseudostratified appearance lining the female atrium and the shape and position of the proximal portion of the prostatic vesicle.

The lack of university funding is one of the major impediments to taxonomy, partly because traditional taxonomic training takes longer than a PhD course. Understanding ranges of phenotypic variability for different morphological structures, and their use as characters for delimitation and description of taxa, is a tedious task. We argue that the advent of molecular barcoding and quantitative shape analysis makes it unnecessary. As an example, we tackle a problematic species-complex of marine copepods from Korea and Japan, approaching it as a starting taxonomist might. Samples were collected from 14 locations and the mitochondrial COI gene was sequenced from 42 specimens. Our phylogenetic analyses reveal four distinct clades in Korea and Japan, and an additional nine belonging to a closely related complex from other parts of the Northern Pacific. Twenty different morphological structures were analysed for one Japanese and two Korean clades using landmark-based two-dimensional geometric morphometrics. Although there is no single morphological character that can distinguish with absolute certainty all three cryptic species, most show statistically significant interspecific differences in shape and size. We use five characters to describe two new species from Korea and to re-describe Tigriopus japonicus Mori, 1938 from near its type locality.

In 2008 the change to the Brazilian legislation regarding the use of natural caves has caused an increase in the number of studies on environmental impacts involving caves. The legislation requires the classification of such environments according to their importance, and caves that are not classified highly may be irreversibly impacted. Thus, caves in rocks of high economic interest have been intensively sampled, which has resulted in the collection of several specimens of Palpigradi in them. The Iron Quadrangle (in Minas Gerais state) stands out among these areas as one the most important sources of iron ore in Brazil. Several palpigrades from this region are housed in collections: most of them belong to the edaphic species Eukoenenia ferratilis, and a small portion belong to new species that are morphologically quite distinct from E. ferratilis, with longer bodies and more elongated appendages, indicating the presence of troglomorphisms. Therefore, the present study aimed to describe three new troglobitic species of Eukoenenia, which can be distinguished morphometrically and by means of some qualitative characters. These descriptions are important for the preservation of the caves where they occur, since the presence of troglobitic species increases the relevance of the caves, which have been severely threatened by mining activities.

Species of the genus Spirobranchus, commonly known as Christmas tree worms, are abundant throughout tropical Indo-Pacific and Atlantic Oceans. Information on the species inhabiting the Red Sea in general and the Gulf of Eilat (Gulf of Aqaba) in particular, has so far been very limited. Here we present a multigene phylogenetic analysis, examining both mitochondrial (Cyt-b) and nuclear (ITS2 and 18S) markers, to support the presence of four distinct Spirobranchus species in the Gulf of Eilat: S. corniculatus (including three taxa previously regarded as full species: S. gaymardi, S. cruciger, and S. corniculatus), S. cf. tetraceros, S. gardineri and a new species Spirobranchus aloni, likely endemic to the Red Sea (including two morphotypes with slightly different opercular morphology). The results presented here emphasise that the combination of molecular and in-depth morphological evaluation holds great prospects for a better understanding of species divergence and relationships.

A new genus and species of the suborder Maricola, representing the first marine triclad living in freshwater within a cave, is described. These flatworms show specialised features, such as a lack of pigmentation and eyes, indicating their troglobitic condition. Until now, cave-dwelling triclads have only been found as representatives of the other two triclad lineages. The phylogenetic trees based on 18S rRNA and 28S rRNA genes showed their sequences to form a clade situated in a rather derived position within the Maricola. Combining maximum likelihood and Bayesian analyses along with morphological studies, we undertake the first integrative description of a marine triclad. The new genus is characterised by a secondary copulatory bursa and ovaries located behind the root of the pharynx. Nevertheless, its assignment to a family of Maricola was a difficult task especially due to the paucity of unique defining morphological features of their families. The new species is found in a semiarid environment that suffered marine transgressions and regressions during the Cretaceous, which may explain the presence of this originally marine species in a freshwater cave. The restricted distribution of the new species and recent environmental conditions detected at its type locality raise major concern for its conservation.

European Lepidocyrtus species are usually grouped into five species-groups within two subgenera, Lepidocyrtus s.s. and Lanocyrtus, defined by the distribution of scale covering and dorsal head and body macrochaetotaxy. The discovery of several Lepidocyrtus populations with morphological characters intermediate between two species-groups suggested the need for the present study to test whether molecular data provide support to these groups. The morphology and gene sequences of 110 specimens belonging to 19 species of European Lepidocyrtus have been studied. Our molecular results are congruent with the distribution of the European species into the five groups established in the literature on the basis of morphological characters, but also indicated that subgenus Lanocyrtus is paraphyletic while subgenus Lepidocyrtus s.s. is monophyletic. A new species, Lepidocyrtus intermedius, is described, and a redefinition of European species-groups is proposed based on chaetotaxy.

The problem of reconciling earthworm taxonomy and phylogeny has shown advances with the application of molecular techniques, yet they have proven insufficient. Integrative systematics could solve this by combining multiple sources of evolutionary information. Relatively low diversity, restricted range and low nomenclatural conflict make Hormogastridae Michaelsen, 1900 a desirable target for an integrative systematics approach. The main systematic conflicts within this family are the polyphyly of the species Hormogaster pretiosa Michaelsen, 1899, the widespread presence of cryptic lineages, the lack of resolution of supraspecific relationships and the paraphyly of the genus Hormogaster Rosa, 1877 (found to be composed of four well-supported genus-level clades by molecular phylogenetic inference). This work integrates all the existing information by performing phylogenetic inference based on morphological, molecular and total evidence datasets, comparing their performance with the topology obtained by phylogenomic analyses. It also includes a comparative study of representatives of the main clades based on microcomputed tomography (µCT) reconstructions. The addition of morphological characters improved the resolution of the Hormogastridae tree; ancestral state reconstruction displayed the evolution of character states and provided morphological diagnoses for the genera within a new system, which incorporates information about ecological niches and biogeography.

The Epicauta stigmata complex is a group of blister beetles composed of three parapatric or sympatric species that occur in central Mexico to southern USA: E. stigmata, E. uniforma and E. melanochroa. These species are morphologically very similar, and are mainly distinguished by body colour differences. Here we assessed whether phenotypic divergence in coloration patterns define evolutionary units within the complex. We studied the phylogenetic relationships, demographic history and concordances between morphological and ecological traits in the group. The complex apparently had a demographic history of recent population expansion during the last glaciation period 75 000 to 9500 years ago. The three species show no reciprocal monophyly, and thus their allospecificity was not confirmed. The current distribution of haplotypes and the genetic divergences in these taxa can be explained by either recent mitochondrial introgression events caused by hybridisation or by incomplete lineage sorting. Colour pattern differences in the complex are not likely a product of local selection acting over a common genetic background. We suggest that phenotypic divergence in colour patterns during an incipient speciation process might be seen as an enhancing factor of cohesion within each of the three evolutionary units.

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.

The Australian plant bug family Miridae is hyperdiverse in Australia, including a remarkable radiation of undescribed species belonging to the tribe Orthotylini. This study includes a comparative morphological and phylogenetic study of a group of orthotylines, mostly associated with woody shrubs. Parsimony-based analysis of 49 morphological characters was undertaken, resulting in the recognition of a monophyletic supraspecific group with elongate heads, the Palassocoris complex, as well as three monophyletic genera with multiple species, and two monotypic genera. Five new genera (Austroloxops, gen. nov., Harpemiris, gen. nov., Hypospicula, gen. nov., Palassocoris, gen. nov. and Wallagootacoris, gen. nov.) and 10 species (Austroloxops juriensis, sp. nov., Harpemiris hibbertiaphila, sp. nov., Hypospicula banksiaphila, sp. nov., Hypospicula finkensis, sp. nov., Palassocoris elongatus, sp. nov., Palassocoris emuensis, sp. nov., Palassocoris jambrecinae, sp. nov., Palassocoris samphirensis, sp. nov., Wallagootacoris schwartzi, sp. nov., Wallagootacoris tasmaniensis, sp. nov.) are described as new to science. The Palassocoris complex was found to be the sister-group to two species of the Lattinova complex, the latter previously assigned to the tribe Austromirini, rendering the Orthotylini as paraphyletic. The classificatory implications of this finding are discussed.