Reliable taxonomy underpins communication in all of biology, not least nature conservation and sustainable use of ecosystem resources. The flexibility of taxonomic interpretations, however, presents a serious challenge for end-users of taxonomic concepts. Users need standardised and continuously harmonised taxonomic reference systems, as well as high-quality and complete taxonomic data sets, but these are generally lacking for non-specialists. The solution is in dynamic, expertly curated web-based taxonomic tools. The Pan-European Species-directories Infrastructure (PESI) worked to solve this key issue by providing a taxonomic e-infrastructure for Europe. It strengthened the relevant social (expertise) and information (standards, data and technical) capacities of five major community networks on taxonomic indexing in Europe, which is essential for proper biodiversity assessment and monitoring activities. The key objectives of PESI were: 1) standardisation in taxonomic reference systems, 2) enhancement of the quality and completeness of taxonomic data sets and 3) creation of integrated access to taxonomic information. This paper describes the results of PESI and its future prospects, including the involvement in major European biodiversity informatics initiatives and programs.

A new species of the giant pill millipede genus Sphaerobelum is described: Sphaerobelum turcosa sp. nov. from the northeastern part of Thailand. Species delimitation is based on morphological characters and COI sequence data. The new species can be clearly discriminated from congeners by its greenish-blue body color, the face mask-like appearance of the thoracic and anal shields jointly when rolled up, and the combination of the following four characters: (1) the coxa of the second leg laterally with a sharp and long process, (2) the tarsi of legs 4–21 with 6–7 ventral spines, (3) the anterior telopods consisting of four conspicuous telopoditomeres, and (4) the immovable, slender (not strongly humped) and distally curved finger of the posterior telopods without a membranous spot. The interspecific COI sequence divergence between the new species and other Sphaerobelum species ranges from 17% to 23% (mean 20%). The intergeneric COI sequence divergence between the new species and Zephronia species ranges from 18% to 21% (mean 20%). The relationships among Sphaerobelum and Zephronia species based on the COI sequence data were not resolved in this study. Sphaerobelum turcosa sp. nov. is restricted to limestone habitat in Loei province and is probably endemic for the Thai fauna.

Many nominal species of microscopic animals traditionally fitting the ‘everything is everywhere’ paradigm have been revealed to be complexes of cryptic species. Here, we explore species diversity within the micrometazoan flatworm Gyratrix hermaphroditus—unique among meiofauna because of its global occurrence in a wide variety of brackish, freshwater and marine environments. With maximum likelihood and Bayesian approaches, we analysed 18S, 28S, 5.8S and ITS2 rDNA sequences from 401 specimens across the global distribution of G. hermaphroditus. Generalized Mixed Yule Coalescent (GMYC) and Automatic Barcode Gap Discovery (ABGD) methods delineated 78 and 62 putative species, respectively. This renders G. hermaphroditus one of the most species‐rich complexes known to date. Based on shape variations of the male copulatory organ, 14 morphotypes corresponding with molecular clades were identified within the species complex. Within morphotypes, morphometric measurements were able to further discriminate between GMYC species using discriminant analyses. While most putative species occur on local or regional scales, over 10% are distributed over vast distances (>500 km apart) and two GMYC and six ABGD species have colonised multiple continents. This suggests that the cosmopolitanism of the G. hermaphroditus species complex is not just caused by mixing cryptic species with a more limited geographic distribution, but is due to the presence of previously unrecognised cosmopolitan taxa. The wide variation in distribution patterns between putative species indicates that meiofaunal biogeography should not be simplified into ‘everything is everywhere’, but rather entails every ecological state, extending from local endemism to true cosmopolitanism.

Hyperdiverse mtDNA with more than 5% of variable synonymous nucleotide sites can lead to erroneous interpretations of population genetic differentiation patterns and parameters (φST, DEST). We illustrate this by using hyperdiverse mtDNA markers to infer population genetic differentiation and connectivity in Melarhaphe neritoides, a NE Atlantic (NEA) gastropod with a high dispersal potential. We also provide a recent literature example of how mtDNA hyperdiversity may have misguided the interpretation of genetic connectivity in the crab Opecarcinus hypostegus. mtDNA variation surveyed throughout the NEA showed that nearly all M. neritoides specimens had haplotypes private to populations, suggesting at first glance a lack of gene flow and thus a strong population genetic differentiation. Yet, the bush-like haplotype network, though visually misleading, showed no signs of phylogeographic or other haplotype structuring. Coalescent-based gene flow estimates were high throughout the NEA, irrespective of whether or not mtDNA hyperdiversity was reduced by removing hypervariable sites. Melarhaphe neritoides seems to be panmictic over the entire NEA, which is consistent with its long-lived pelagic larval stage. With hyperdiverse mtDNA, the apparent lack of shared haplotypes among populations does not necessarily reflect a lack of gene flow and/or population genetic differentiation by fixation of alternative haplotypes (DEST ≈ 1 does not a fortiori imply φST ≈ 1), but may be due to (1) a too low sampling effort to detect shared haplotypes and/or (2) a very high mutation rate that may conceal the signal of gene flow. Hyperdiverse mtDNA can be used to assess connectivity by coalescent-based methods. Yet, the combined use of φST and DEST can provide a reasonable inference of connectivity patterns from hyperdiverse mtDNA, too.