Summary The uncertainty or the provisional status of a taxonomic identification can be expressed by a set of terms and abbreviations known as Open Nomenclature (ON) qualifiers. This approach is widely applied across biological disciplines, and a high amount of biodiversity data left in ON can be found in literature and data bases. However, there is no consensus about ON qualifiers and their meaning. The use of ON qualifiers has been reviewed in order to provide a summary and guide to current practice in zoology. Some recommendation is given to avoid inconsistencies or vagueness. A flow chart is proposed to clarify the sources of uncertainties during identification and to facilitate the application of ON qualifiers. This review provides a guide for taxonomists and ecologists currently involved in biomonitoring and biodiversity programmes, as well as for researchers dealing with biodiversity data infrastructures and tools, offering a starting point for a methodological harmonization.

Tidal channels are crucial for the functioning of wetlands, though their morphological properties, which are relevant for seafloor habitats and flow, have been understudied so far. Here, we release a dataset composed of Digital Terrain Models (DTMs) extracted from a total of 2,500 linear kilometres of high-resolution multibeam echosounder (MBES) data collected in 2013 covering the entire network of tidal channels and inlets of the Venice Lagoon, Italy. The dataset comprises also the backscatter (BS) data, which reflect the acoustic properties of the seafloor, and the tidal current fields simulated by means of a high-resolution three-dimensional unstructured hydrodynamic model. The DTMs and the current fields help define how morphological and benthic properties of tidal channels are affected by the action of currents. These data are of potential broad interest not only to geomorphologists, oceanographers and ecologists studying the morphology, hydrodynamics, sediment transport and benthic habitats of tidal environments, but also to coastal engineers and stakeholders for cost-effective monitoring and sustainable management of this peculiar shallow coastal system.

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The European Alien Species Information Network (EASIN; http://easin.jrc.ec.europa.eu) aims to facilitate the exploration of existing alien species information from distributed sources through a network of interoperable web services, and to assist the implementation of European policies on biological invasions. The network allows extraction of alien species information from online information systems for all species included in the EASIN catalogue. This catalogue was based on an inventory of reported alien species in Europe that was produced by reviewing and standardizing information from 43 online databases. It includes information on taxonomy, synonyms, common names, pathways of introduction, native range in Europe, and impact. EASIN catalogue entails the basic information needed to efficiently link to existing online databases and retrieve spatial information for alien species distribution in Europe. Using search functionality powered by a widget framework, it is possible to make a tailored selection of a subgroup of species based on various criteria (e.g., environment, taxonomy, pathways). Distribution maps of the selected species can be produced dynamically and downloaded by the user. The EASIN web tools and services follow internationally recognized standards and protocols, and can be utilized freely and independently by any website, while ownership of the data remains with its source, which is properly cited and linked.

M-AMBI is a multimetric index for assessing the ecological quality status of marine and transitional waters. It is based on benthic macroinvertebrates and integrates AMBI, a biotic index based on species sensitivity/tolerance, with diversity and richness, making it compliant with the European Water Framework Directive. The success of AMBI paved the way for the introduction of M-AMBI, which was subsequently incorporated into the regulations of several European countries. The M-AMBI algorithm integrates the metrics by means of factor analysis (FA). In this paper, we first reproduced the algorithm using the open source R software. This enabled us to point out that FA is not functional to M-AMBI, and its omission does not appreciably change the results. We then enhanced the applicability of the index, making it independent of the number of samples. In this way, M-AMBI is closely approximated by the simple mean of the normalised metrics with no need for multivariate techniques. Finally, we further simplified the approach, presenting a bivariate version that is still highly correlated with M-AMBI, in which the constitutive metrics are reduced to a diversity measure and a species sensitivity index. The properties of this bivariate version include simplicity, transparency, robustness, and openness.

Sabellidae are among the most visible polychaetes of the hard substrate fouling communities and are colonizing new geographic areas. The fouling community was surveyed in 25 shallow coastal estuaries on the Atlantic and Pacific coasts of the United States with the specific goal of detecting non-indigenous species. During surveys in 2012 and 2014, specimens of Branchiomma coheni Tovar-Hernández and Knight-Jones, 2006 were found for the first time in Tampa Bay, Florida, occurring at the same marina site (27°53'7.58"N, 82°32'2.29"W) each year and suggesting it is established here. The species was not detected at other sites surveyed in the United States, and has not been reported from the eastern Atlantic or the Mediterranean basin. Type material of B. coheni, specimens from southern Gulf of California, and specimens from the Pacific coast of Mexico, were used to corroborate identification. The transfer of this species by ships via the Panama Canal is a probable mechanism of introduction, based on the current known distribution and shipping traffic patterns. This represents the first record of the species in the Atlantic Ocean. A worldwide update of the records of this species and a list of valid species of the genus Branchiomma with notes on introduced populations are provided, as well as recommendations for accurate identification and sampling.

This study was performed to analyse the genetic and morphological diversity of the sabellid annelid genus Branchiomma, with special emphasis on a taxon so far identified as Branchiomma bairdi. This species, originally described from Bermuda, has frequently been reported as an invader in the Mediterranean, the Atlantic and the Eastern Pacific, but recent observations have raised some taxonomic questions. Samples of this taxon were collected from five sites in the Mediterranean Sea, two sites in the original distribution area of B. bairdi in the Gulf of Mexico and four localities in the east Pacific and Atlantic Oceans where B. bairdi has been reported as invasive. The molecular results revealed a conspicuous genetic divergence (18.5% K2P) between the sampled Mediterranean populations and all the other ones that led to a re-evaluation of their morphological characters. The latter showed that the Mediterranean and extra-Mediterranean populations also differ in some discrete morphological and reproductive features. Consequently, the Mediterranean samples were re-designated as B. boholense, another non-indigenous species originally described from Philippines. Branchiomma bairdi and B. boholense differ in body size, development and shape of micro and macrostylodes, size of radiolar eyes and body pigmentation. Genetic diversity was high in B. boholense from the Mediterranean as well as in B. bairdi from the Gulf of Mexico, but low in B. bairdi populations outside their native range. The phylogenetic analysis revealed the presence of connections between the Mediterranean localities as well as between native and introduced B. bairdi populations that focus the attention on the Panama Canal as important passage for the introduction of the species from the Gulf of Mexico to the north-east Pacific Ocean.

Serpulids are an important component of fouling communities. This paper provides an overview of the serpulid species found in North America, as part of a broader study of fouling invertebrates focused on NIS (non-indigenous species) in United States coastal ecosystems. Almost 4400 serpulid specimens were examined from selected fouling plates. Fouling plates were deployed in 26 bays and coastal lagoons along the continental coasts of the United States and Hawaiian islands, primarily in bays and lagoons with salinities averaging 20‰ or greater. Twenty-five serpulid species were identified, including four new records for the United States (Ficopomatus uschakovi, Hydroides cf. brachyacantha, H. longispinosa and Protula longiseta), three known NIS, two presumed NIS, three cryptogenic serpulids, and several range extensions. Crucigera websteri extends its northward range from Santa Barbara Island to Humboldt Bay, California; Ficopomatus enigmaticus, first recorded in North America from San Francisco, California in 1920, Rockport, Texas in 1952 and Barnegat Bay, New Jersey in 1980, is now recorded at additional localities on the east coast (Chesapeake Bay, Virginia, Charleston, South Carolina and Indian River, Florida) and the northern Gulf of Mexico (Galveston Bay, Texas); F. miamiensis extends its westward range from Louisiana to Texas; F. uschakovi, an Indo-Pacific and Western African species, was recorded formally for the first time from the northern Gulf of Mexico (Galveston Bay and Corpus Christi, Texas) and the east coast of Florida (Jacksonville). Hydroides cf. brachyacantha extends its northward range from Curaҫao to Pensacola Bay, Florida; H. dirampha from Veracruz, Mexico to Corpus Christi, Texas; H. floridana extends its westward range from Louisiana to Texas; H. gracilis extends its northward range from Pacific Grove to San Francisco, California; Salmacina huxleyi from Cape Hatteras, North Carolina to Rhode Island; and Spirobranchus minutus from Veracruz, Mexico to Pensacola Bay, Florida. The following additional species range extensions are provisional in that they represent only one record or were not found in the most recent surveys (e.g., Hydroides elegans - east coast): H. longispinosa from Marshall Islands to Oahu, Hawaii; Protula balboensis from Florida to Texas; P. longiseta from the Mexican Caribbean to the Indian River, Florida; H. elegans from San Francisco to Humboldt Bay, northern California and on the east coast from the Indian River, Florida, to Cape Cod, Massachusetts. Among surveyed bays, Biscayne Bay, Florida and Corpus Christi, Texas (northern Gulf of Mexico) had the greatest number of species (14 and 8, respectively); in contrast, almost all sites in Alaska, Washington, Oregon (northwest Pacific), Rhode Island, Virginia and South Carolina (Atlantic) had only one or two species each. Hydroides dianthus was, by far, the most abundant serpulid species on fouling plates in the northern Gulf of Mexico and the east coast, while Pseudochitinopoma occidentalis was the most abundant serpulid detected on the west coast. For each species recorded herein, we include the synonyms and some key references, a material studied section, a diagnosis, and updated distributional information. A checklist and identification key to the known shallow-water serpulids sensu stricto of the United States are included.