Decadal decline of dominant copepod species in the North Sea is associated with ocean warming: Importance of marine heatwaves.

Time-series are crucial to understand the status of zooplankton communities and to anticipate changes that might affect the entire food web. Long-term time series allow us to understand impacts of multiple environmental and anthropogenic stressors, such as chemical pollution and ocean warming, on the marine ecosystems. Here, a recent time series (2018-2022) of abundance data of four dominant calanoid and one harpacticoid copepod species from the Belgian Part of the North Sea was combined with previously collected (2009-2010, 2015-2016) datasets for the same study area. The time series reveals a significant decrease (up to two orders of magnitude) in calanoid copepod abundance (Temora longicornis, Acartia clausi, Centropages spp., Calanus helgolandicus), while this was not the case for the harpacticoid Euterpina acutifrons. We applied generalized additive models to quantify the relative contribution of temperature, nutrients, salinity, primary production, turbidity and pollution (anthropogenic chemicals, i.e., polychlorinated biphenyls and polycyclic aromatic hydrocarbons) to the population dynamics of these species. Temperature, turbidity and chlorophyll a concentrations were the only variables consistently showing a relative high contribution in all models predicting the abundances of the selected species. The observed heat waves which occurred during the summer periods of the investigated years coincided with population collapses (versus population densities in non-heatwave years) and are considered the most likely cause for the observed copepod abundance decreases. Moreover, the recorded water temperatures during these heatwaves correspond to the physiological thermal limit of some of the studied species. As far as we know, this is the first study to observe ocean warming and marine heat waves having such a dramatic impact (population collapse) on the dominant zooplankton species in shallow coastal areas.

Discovery of a Lineage of Soil-Dwelling Medetera Species with Multi-Coloured Eyes in Southern Europe (Diptera: Dolichopodidae).

Seven species in the genus Medetera (Diptera: Dolichopodidae) are described here: Medetera aglaops sp. nov., Medetera corsicana sp. nov., Medetera gibbosipyga sp. nov., Medetera hispanica sp. nov., Medetera lusitana sp. nov., Medetera parva sp. nov., and Medetera rectipyga sp. nov. They all originate from the wider Mediterranean region in southwestern Europe (Iberian Peninsula, southern France, Corsica, Sardinia). The most striking feature in most of the species is the bi- or multicolour pattern of the eyes, most conspicuous in Medetera aglaops sp. nov. and Medetera lusitana sp. nov. This character is shared by the male and female sex and is thus not regarded as Male Secondary Sexual Character. All species belong to the Medetera apicalis species group sensu Bickel and are closely related based on shared characters in the hypandrium and cercus. Interestingly, three species with and four species without the basal pair of anterodorsal and posterodorsal bristles on the mid tibia are represented. This suggests that this diagnostic character has less phylogenetic relevance than previously anticipated. Unlike most Palaearctic Medetera, at least five of the new species are mostly found on rocky substrates in dry biotopes with a sclerophyllous vegetation. This further supports their relationship with species of the Medetera muralis subclade sensu Pollet, Germann and Bernasconi.

LifeWatch observatory data: phytoplankton observations in the Belgian Part of the North Sea.

BACKGROUND: This paper describes a phytoplankton data series generated through systematic observations in the Belgian Part of the North Sea (BPNS). Phytoplankton samples were collected during multidisciplinary sampling campaigns, visiting nine nearshore stations with monthly frequency and an additional eight offshore stations on a seasonal basis. NEW INFORMATION: The data series contain taxon-specific phytoplankton densities determined by analysis with the Flow Cytometer And Microscope (FlowCAM®) and associated image-based classification. The classification is performed by two separate semi-automated classification systems, followed by manual validation by taxonomic experts. To date, 637,819 biological particles have been collected and identified, yielding a large dataset of validated phytoplankton images. The collection and processing of the 2017-2018 dataset are described, along with its data curation, quality control and data storage. In addition, the classification of images using image classification algorithms, based on convolutional neural networks (CNN) from 2019 onwards, is also described. Data are published in a standardised format together with environmental parameters, accompanied by extensive metadata descriptions and finally labelled with digital identifiers for traceability. The data are published under a CC-BY 4.0 licence, allowing the use of the data under the condition of providing the reference to the source.

A new species of Pherbellia (Diptera: Sciomyzidae) from Iran.

Pherbellia jalili Mortelmans Kazerani sp. nov. is described based on 5 males and 4 females. The new species is associated with old deciduous forest and is found only in the Hyrcanean forest in Iran. It is compared with its sister species, P. annulipes (Zetterstedt, 1846), and a comprehensive distribution map for both species is given. The key to species of this group of Pherbellia is updated including the Japanese Pherbellia tricolor Sueyoshi, 2001. Barcodes are generated for P. jalili sp. nov., P. annulipes, and P. nana nana (Fallén, 1820).

Review of Euthycerina Malloch (Diptera, Sciomyzidae), with description of a new species from Chile.

We review and summarize the present knowledge of the Neotropical genus Euthycerina Malloch, 1933. Habitus and male terminalia are described and figured in detail for the first time. Euthycerina uachi sp. nov. is described, based on two males and four females from two locations in the province of Valdivia, Chile. An illustrated key is given for the three described species of Euthycerina, together with maps, phenology plots, and a summary of diagnostic characters that will enable researchers to confidently identify all species of Euthycerina.

Nutrient, pigment, suspended matter and turbidity measurements in the Belgian part of the North Sea.

Through regular sampling surveys, the Flanders Marine Institute is generating long term data series for the Belgian coastal water and sand bank systems, a designated site in the Long Term Ecological Research (LTER) network. The data series is built on sampling activities initiated in 2002, but gradually upgraded and extended in the framework of the LifeWatch marine observatory and the Integrated Carbon Observation System (ICOS) participation. Nine nearshore stations are sampled monthly, with additional seasonal sampling of eight offshore stations. This paper presents the generated data series for nutrients, pigments, suspended matter and turbidity. The collection, methodology and processing of the 2002-2018 dataset is described, along with its data curation, integration and quality control. Yearly versions of the data are published online in a standardized format, accompanied with extensive metadata description and labelled with digital identifiers for traceability. Data is published under a CC-BY license, allowing use of the data under the condition of providing reference to the original source.

A remarkable new species of Paraphamartania Engel from Portugal (Diptera, Asilidae).

Paraphamartania marvaoensis sp. nov. is described based on three male and one female specimens from Marvão, Portugal. The discovery of this new species of Paraphamartania is of great significance since it shows the occurrence of a second species of Paraphamartania in the western Mediterranean. High resolution pictures of type material of all three species of Paraphamartania are provided together with a key to these three species. DNA barcodes of this new species are provided, so future workers are able to study relationships of Paraphamartania.

Using DNA barcodes for assessing diversity in the family Hybotidae (Diptera, Empidoidea).

Empidoidea is one of the largest extant lineages of flies, but phylogenetic relationships among species of this group are poorly investigated and global diversity remains scarcely assessed. In this context, one of the most enigmatic empidoid families is Hybotidae. Within the framework of a pilot study, we barcoded 339 specimens of Old World hybotids belonging to 164 species and 22 genera (plus two Empis as outgroups) and attempted to evaluate whether patterns of intra- and interspecific divergences match the current taxonomy. We used a large sampling of diverse Hybotidae. The material came from the Palaearctic (Belgium, France, Portugal and Russian Caucasus), the Afrotropic (Democratic Republic of the Congo) and the Oriental realms (Singapore and Thailand). Thereby, we optimized lab protocols for barcoding hybotids. Although DNA barcodes generally well distinguished recognized taxa, the study also revealed a number of unexpected phenomena: e.g., undescribed taxa found within morphologically very similar or identical specimens, especially when geographic distance was large; some morphologically distinct species showed no genetic divergence; or different pattern of intraspecific divergence between populations or closely related species. Using COI sequences and simple Neighbour-Joining tree reconstructions, the monophyly of many species- and genus-level taxa was well supported, but more inclusive taxonomical levels did not receive significant bootstrap support. We conclude that in hybotids DNA barcoding might be well used to identify species, when two main constraints are considered. First, incomplete barcoding libraries hinder efficient (correct) identification. Therefore, extra efforts are needed to increase the representation of hybotids in these databases. Second, the spatial scale of sampling has to be taken into account, and especially for widespread species or species complexes with unclear taxonomy, an integrative approach has to be used to clarify species boundaries and identities.