A multi-taxon analysis of European Red Lists reveals major threats to biodiversity

Biodiversity loss is a major global challenge and minimizing extinction rates is the goal of several multilateral environmental agreements. Policy decisions require comprehensive, spatially explicit information on species' distributions and threats. We present an analysis of the conservation status of 14,669 European terrestrial, freshwater and marine species (ca. 10% of the continental fauna and flora), including all vertebrates and selected groups of invertebrates and plants. Our results reveal that 19% of European species are threatened with extinction, with higher extinction risks for plants (27%) and invertebrates (24%) compared to vertebrates (18%). These numbers exceed recent IPBES (Intergovernmental Platform on Biodiversity and Ecosystem Services) assumptions of extinction risk. Changes in agricultural practices and associated habitat loss, overharvesting, pollution and development are major threats to biodiversity. Maintaining and restoring sustainable land and water use practices is crucial to minimize future biodiversity declines.

Atlantor, a new generic name for Barbus reinii Günther, 1874 from Morocco(Teleostei: Cyprinidae)

Atlantor, new genus, is proposed for Barbus reinii from the Atlantic basin in Morocco. The sole species of the genus is clearly separated from related genera based on its phylogenetic position, and from Carasobarbus, Mesopotamichthys and Pterocapoeta in its morphological characters. Atlantor was previously included in Labeobarbus, making this genus paraphyletic with respect to several genera from Western Asia and North Africa. With the description of Atlantor, all these genera become monophyletic. Within Torinae, Atlantor can be diagnosed by having 5½ branched anal-fin rays, modally 8½ branched dorsal-fin rays, two pairs of long barbels, and by its distinct phylogenetic position.

Glyptothorax vatandousti, a new species of torrent catfish from the upper Karkheh drainage in Iran (Teleostei: Sisoridae)

Glyptothorax vatandousti, new species, from the upper Karkheh drainage, a tributary of the Iranian Tigris, is distinguished from its congeners in the Persian Gulf basin by having the flank with a fine, pale-brown mottled pattern overlaid by small and large, blackish or dark-brown blotches, deep caudal-peduncle (its depth 1.1-1.3 times in length), and without, or with a pale-brown triangle-shaped blotch in front of dorsal-fin origin.

Two new freshwater blennies from the Eastern Mediterranean basin (Teleostei: Blenniidae)

Two new species of Salariopsis are described from the Eastern Mediterranean basin. Salariopsis burcuae, new species, from the Bay of Antalya east to the Jordan, is characterised by having a short cirrus, usually not overlapping the 9th circum-orbital sensory pore, and many tiny black dots on the cheek not organised in rows or bands. The new species shows a 4.1% K2P sequence divergence on the cytochrome-c-oxidase subunit 1 (COI) barcoding region from its closest relative, S. fluviatilis. Salariopsis renatorum, new species, from the upper Ceyhan drainage and a coastal stream in Arsuz, is distinguished by having an unbranched supraocular tentacle, black lateral line pores, a short snout, and no black dots on the upper part of the flank and on the cheek. It is also distinguished from its geographically closest congener, S. burcuae, by a molecular distance of 8.8% K2P in its COI barcode region.

Mystus misrai Anuradha, 1986, a valid species from the Orontes drainage (Teleostei: Bagridae)

Mystus misrai from the northern Orontes drainage (Mediterranean Sea basin) is re-examined and recognised as a valid species. It is distinguished from M. pelusius from the Gulf basin by the lack of stripes on the flank, shorter fins, the eye situated below the dorsal head profile, and a K2P distance of 7.3% in its COI barcoding gene. Mystus misrai is likely Critically Endangered: only a single, spring-fed lake in Türkiye is known as its habitat. The biogeographic connection between the Orontes and the Gulf is discussed based on molecular data of 27 species native to the region.

Barbus urmianus, a synonym of Barbus cyri (Teleostei: Cyprinidae)

Barbus urmianus, from the upper Mahabad River in Lake Urmia basin, was distinguished from B. cyri based on several morphological characters. Our analysis demonstrated very small molecular (COI) differences between both species and mostly overlapping or identic morphological character states. Therefore, Barbus urmianus is treated as a junior synonym of B. cyri.

Spatial priorities for freshwater biodiversity conservation in light of catchment protection and connectivity in Europe

Freshwater ecosystems host disproportionately high numbers of species relative to their surface area yet are poorly protected globally. We used data on the distribution of 1631 species of aquatic plant, mollusc, odonate and fish in 18,816 river and lake catchments in Europe to establish spatial conservation priorities based on the occurrence of threatened, range-restricted and endemic species using the Marxan systematic conservation planning tool. We found that priorities were highest for rivers and ancient lakes in S Europe, large rivers and lakes in E and N Europe, smaller lakes in NW Europe and karst/limestone areas in the Balkans, S France and central Europe. The a priori inclusion of well-protected catchments resulted in geographically more balanced priorities and better coverage of threatened (critically endangered, endangered and vulnerable) species. The a priori exclusion of well-protected catchments showed that priority areas that need further conservation interventions are in S and E Europe. We developed three ways to evaluate the correspondence between conservation priority and current protection by assessing whether a cathment has more (or less) priority given its protection level relative to all other catchments. Each method found that priority relative to protection was high in S and E Europe and generally low in NW Europe. The inclusion of hydrological connectivity had little influence on these patterns but decreased the coverage of threatened species, indicating a trade-off between connectivity and conservation of threatened species. Our results suggest that catchments in S and E Europe need urgent conservation attention (protected areas, restoration, management, species protection) in the face of imminent threats such as river regulation, dam construction, hydropower development and climate change. Our study presents continental-scale conservation priorities for freshwater ecosystems in ecologically meaningful planning units and will thus be important in freshwater biodiversity conservation policy and practice, and water management in Europe.

Contributions to the biodiversity of Vietnam – Results of VIETBIO inventory work and field training in Cuc Phuong National Park

VIETBIO [Innovative approaches to biodiversity discovery and characterisation in Vietnam] is a bilateral German-Vietnamese research and capacity building project focusing on the development and transfer of new methods and technology towards an integrated biodiversity discovery and monitoring system for Vietnam. Dedicated field training and testing of innovative methodologies were undertaken in Cuc Phuong National Park as part and with support of the project, which led to the new biodiversity data and records made available in this article collection.

VIETBIO is a collaboration between the Museum für Naturkunde Berlin – Leibniz Institute for Evolution and Biodiversity Science (MfN), the Botanic Garden and Botanical Museum, Freie Universität Berlin (BGBM) and the Vietnam National Museum of Nature (VNMN), the Institute of Ecology and Biological Resources (IEBR), the Southern Institute of Ecology (SIE), as well as the Institute of Tropical Biology (ITB); all Vietnamese institutions belong to the Vietnam Academy of Science and Technology (VAST).

The article collection "VIETBIO" (https://doi.org/10.3897/bdj.coll.63) reports original results of recent biodiversity recording and survey work undertaken in Cuc Phuong National Park, northern Vietnam, under the framework of the VIETBIO project. The collection consist of this “main” cover paper – characterising the study area, the general project approaches and activities, while also giving an extensive overview on previous studies from this area – followed by individual papers for higher taxa as studied during the project. The main purpose is to make primary biodiversity records openly available, including several new and interesting findings for this biodiversity-rich conservation area. All individual data papers with their respective primary records are expected to provide useful baselines for further taxonomic, phylogenetic, ecological and conservation-related studies on the respective taxa and, thus, will be maintained as separate datasets, including separate GUIDs also for further updating.

Genetic relationships between sympatric and allopatric Coregonus ciscoes in North and Central Europe

BACKGROUND

Sympatric speciation along ecological gradients has been studied repeatedly, in particular in freshwater fishes. Rapid post-glacial ecological divergence has resulted in numerous endemic species or ecologically distinct populations in lakes of the temperate zones. Here, we focus on the Baltic cisco (Coregonus albula) complex, to study the genetic similarity among two pairs of sympatric autumn- and spring-spawning populations from post-glacial German Lakes Stechlin and Breiter Luzin. For comparison, we included a similar pair of sympatric populations from the Swedish Lake Fegen. We wanted to explore potential genetic similarities between the three sympatric cisco population pairs in the three lakes, to evaluate whether the pairs may have emerged independently in the three lakes, or whether two different species may have colonized all three lakes independently. Furthermore, we considered allopatric C. albula populations from three Polish, three Finnish, and four Swedish locations, added one Siberian population of the sister species C. sardinella and a Swedish C. maraena (whitefish) population. By genotyping nine microsatellite markers in 655 individuals from these 18 populations, we wanted to elucidate how strongly the cisco populations differ across a larger geographical area within Europe. Finally, we compared the genetic differences between the spring- and autumn-spawning populations of ciscoes in the two German lakes to infer the potentially deteriorating effect of strong anthropogenic pressure on the lakes.

RESULTS

Dendrogram, Principal Coordinate Analysis and admixture analysis all indicated strong correspondence between population differentiation and geographical location for most cisco populations in Europe, including the Siberian population of C. sardinella. However, populations from some Swedish lakes deviated from this general pattern, by showing a distinct genetic structure. We found evidence for independent evolution of the three sympatric population pairs, because the populations co-occurring in the same lake were always most closely related. However, genetic differentiation was weak in the two German population pairs, but strong in the Swedish Lake Fegen, indicating that the weak differentiation in the German pairs reported earlier has eroded further.

CONCLUSIONS

Our results suggest that the genetic differentiation at neutral genetic markers among populations of the Baltic cisco complex has evolved (and is maintained) by random genetic drift in isolated populations. However, earlier studies on the Swedish populations combining mitochondrial DNA and microsatellite data indicate that also post-glacial immigration from separate glacial refugia has shaped the present genetic population structure. The low neutral differentiation of the German sympatric pairs in contrast to the Swedish pair suggests that recent anthropogenic effects on the lakes in Germany may put the endemic spring-spawners at risk to extinction.

Oxynoemacheilus isauricus, a new nemacheilid loach from Central Anatolia (Teleostei: Nemacheilidae)

Oxynoemacheilus isauricus, new species, from the Lakes Beyşehir and Suğla basins in Central Anatolia is distinguished from all other species of the O. angorae group by having a very slender caudal peduncle (its depth 2.22.6 times in its length). The new species is further distinguished by having a short head (head length 2124% SL), and a midlateral series of irregularly shaped blotches on the flank. Oxynoemacheilus isauricus is also distinguished by a minimum K2P sequence divergence of 7.5% and 8.0% in the mtDNA-COI barcode region from O. eregliensis and O. atili, its closest relatives.

Oxynoemacheilus nasreddini, a new nemacheilid loach from Central Anatolia (Teleostei: Nemacheilidae)

Oxynoemacheilus nasreddini, new species, from Lake Akşehir, Eber, Eğirdir, and Ilgın basins in Central Anatolia is distinguished from other species of Oxynoemacheilus in Central Anatolia by having irregularly shaped blotches on flank; 24 dark-brown bands on caudal fin; a slender body, and an emarginate caudal fin in which the shortest middle caudal-fin ray is 7691% of the longest ray of the upper caudal-fin lobe. Molecular data suggest that the new species is closely related to O. mediterraneus from the Aksu and Köprüçay drainages. Although the two species are separated by only a minimum K2P distance of 1.2% in the mtDNA COI barcode region, they are well distinguished morphologically. The situation is complicated by loaches from Lake Eğirdir basin that are identified as O. nasreddini by their morphological character states but are only distinguished from O. mediterraneus by a minimum K2P distance of 0.2% in the mtDNA COI barcode region.

A genomic perspective on an old question: Salmo trouts or Salmo trutta (Teleostei: Salmonidae)?

There are particular challenges in defining the taxonomic status of recently radiated groups due to the low level of phylogenetic signal. Members of the Salmo trutta species-complex, which mostly evolved during and following the Pleistocene, show high morphological and ecological diversity that, along with their very wide geographic distribution, have led to morphological description of 47 extant nominal species. However, many of these species have not been supported by previous phylogenetic studies, which could be partly due to lack of significant genetic differences among them, the limited resolution offered by molecular methods previously used, as well as the often local scale of these studies. The development of next-generation sequencing (NGS) and related analytical tools have enhanced our ability to address such challenging questions. In this study, Genotyping-by-Sequencing (GBS) of 15,169 filtered SNPs and mitochondrial DNA (mtDNA) D-loop sequences were combined to assess the phylogenetic relationships among 166 brown trouts representing 21 described species and three undescribed groups collected from 84 localities throughout their natural distribution in Europe, west Asia, and North Africa. The data were analysed using different clustering algorithms (admixture analysis and discriminant analysis of principal components-DAPC), a Bayes Factor Delimitation (BFD) test, species tree reconstruction, gene flow tests (three- and four-population tests), and Rogue taxa identification tests. Genomic contributions of the Atlantic lineage brown trout were found in all major sea basins excluding the North African and Aral Sea basins, suggesting introgressive hybridization of native brown trouts driven by stocking using strains of the Atlantic lineage. After removing the phylogenetic noise caused by the Atlantic brown trout, admixture clusters and DAPC clustering based on GBS data, respectively, resolved 11 and 13 clusters among the previously described brown trout species, which were also supported by BFD test results. Our results suggest that natural hybridization between different brown trout lineages has probably played an important role in the origin of several of the putative species, including S. marmoratus, S. carpio, S. farioides, S. pellegrini, S. caspius (in the Kura River drainage) and Salmo sp. in the Danube River basin. Overall, our results support a multi-species taxonomy for brown trouts. They also resolve some species in the Adriatic-Mediterranean and Black Sea drainages as members of very closely related genomic clusters that may need taxonomic revision. However, any final conclusions pertaining to the taxonomy of the brown trout complex should be based on an integrative approach combining genomic, morphological, and ecological data. To avoid challenges in taxonomy and conservation of species complexes like brown trouts, it is suggested to describe species based on genomic clusters of populations instead of describing species based only on morphologically differentiated single type populations.

The Glyptothorax catfishes of the Euphrates and Tigris with the description of a new species (Teleostei: Sisoridae)

The Glyptothorax species inhabiting the Euphrates and Tigris drainages are reviewed and six species are recognised, one of which is described herein as new species. Glyptothorax armeniacus is endemic to headwater streams in the Euphrates drainage. Glyptothorax kurdistanicus is endemic to the upper Tigris downstream to the Lesser Zab drainage. Glyptothorax cous and G. steindachneri are riverine species widespread in both the Euphrates and Tigris drainages. Glyptothorax silviae is endemic to Iran. Glyptothorax daemon, new species, from the Greater Zab and Yanarsu in the upper Tigris drainage, is distinguished by having the thoracic adhesive apparatus strongly elevated, 1.11.2 times longer than wide, without tubercles on the head, well developed anteromedial striae, the medial pit without striae, and a short adipose fin. Glyptothorax daemon is separated into two mitochondrial lineages, externally indistinguishable and separated by a minimum K2P distance of 2.0% in the DNA barcode region. These lineages are paraphyletic in our analysis indicating past introgressive hybridisation with G. cous. All six species are diagnosed and all, except unstudied G. steindachneri, form distinct mitochondrial clades with between 1.2% and 3.4% minimum K2P distance between them. Species from the Euphrates and Tigris form a monophyletic mitochondrial group separated from 53 other Glyptothorax species studied from India and areas further east.

Oxynoemacheilus sarus/, a new nemacheilid loach from the lower Ceyhan and Seyhan in southern Anatolia (Teleostei: Nemacheilidae)

Oxynoemacheilus sarus, new species, is described from the lower Ceyhan and Seyhan drainages in southern Anatolia. It is distinguished from other Oxynoemacheilus species in Cilicia (including the Göksu, Seyhan and Ceyhan drainages) by possession of a series of irregularly shaped midlateral blotches, 3-5 dark-brown bands on the caudal fin, a complete lateral line, a forked caudal fin (shortest middle caudal-fin ray is 56-70% of longest ray of the upper caudal-fin lobe), the caudal peduncle depth 1.4-1.8 times in its length, and a suborbital groove in male individuals. The new species occurs in sympatry with superficially similar O. seyhanicola and O. evreni, and is distinguished by colour pattern as well as morphometric and molecular characters. Molecular data suggest that the closest relatives to the new species in our dataset are O. euphraticus and O. shehabi, which is characterised by a minimum K2P distance of 3.6% and 3.8%, respectively, in the COI mtDNA barcode region.

A metric for spatially explicit contributions to science-based species targets

The Convention on Biological Diversity's post-2020 Global Biodiversity Framework will probably include a goal to stabilize and restore the status of species. Its delivery would be facilitated by making the actions required to halt and reverse species loss spatially explicit. Here, we develop a species threat abatement and restoration (STAR) metric that is scalable across species, threats and geographies. STAR quantifies the contributions that abating threats and restoring habitats in specific places offer towards reducing extinction risk. While every nation can contribute towards halting biodiversity loss, Indonesia, Colombia, Mexico, Madagascar and Brazil combined have stewardship over 31% of total STAR values for terrestrial amphibians, birds and mammals. Among actions, sustainable crop production and forestry dominate, contributing 41% of total STAR values for these taxonomic groups. Key Biodiversity Areas cover 9% of the terrestrial surface but capture 47% of STAR values. STAR could support governmental and non-state actors in quantifying their contributions to meeting science-based species targets within the framework.

emOxynoemacheilus/em emphasicus/em, a new nemacheilid loach from the eastern Black Sea basin with some remarks on other Caucasian emOxynoemacheilus/em (Teleostei: Nemacheilidae)

Oxynoemacheilus phasicus, new species, is described from the Rioni and Enguri River drainages in Georgia. It is distinguished from other Oxynoemacheilus species in the O. brandtii group by a mottled or marbled flank pattern in adults, a slightly emarginate caudal fin, and a deep caudal peduncle. Molecular data suggest that the new species is characterized by a minimum K2P distance of 7.5% from O. brandtii from the Kura drainage in the mtDNA COI barcode region. Oxynoemacheilus brandtii and O. elsae are re-diagnosed. A very slender Oxynoemacheilus from the Aras drainage clusters as sister to O. elsae in our molecular analysis and not with O. brandtii from the Kura River. However, it is identified as O. brandtii as it is indistinguishable from this species in morphological characters.

emGarra/em emorontesi/em, a new species from the Orontes River drainage (Teleostei: Cyprinidae)

Garra orontesi, new species, is described from the Orontes River drainage in the eastern Mediterranean Sea basin in Turkey and Syria. It is distinguished from its congeners in the Mediterranean Sea basin and adjacent Mesopotamia by possessing 17-21 gill rakers on the lower part of the first gill arch, the pelvic-fin origin usually below the second branched dorsal-fin ray, 8½ branched dorsal-fin rays, usually 2-3 scales between the tip of the pectoral and pelvic-fin origins, and no tubercles behind the upper posterior eye margin. It is also distinguished by a minimum K2P distance of 2.7% in its COI barcode region against G. rufa, and 3.9% against the geographically adjacent G. turcica.

Oxynoemacheilus amanos, a new nemacheilid loach from the Orontes River drainage (Teleostei: Nemacheilidae)

Oxynoemacheilus amanos, new species, is described from İncesu spring in the upper Hupnik drainage, a northern tributary of the lower Orontes in Turkey. It is distinguished from the other Oxynoemacheilus species in the Eastern Mediterranean Sea basin by possession of an incomplete lateral line with 23-45 pores, terminating between the vertical through the dorsal fin origin and the anus, 10-13 pores in the infraorbital canal, a deeply emarginate caudal fin, no suborbital groove in the male, and a series of irregularly shaped and set dark-brown bars on the flank, not connected to saddles on the back.

Oxynoemacheilus shehabi, a new nemacheilid loach from the upper Orontes in southern Syria (Teleostei: Nemacheilidae)

Oxynoemacheilus shehabi, new species, is described from the upper Orontes in southern Syria. It is distinguished from other Oxynoemacheilus species in the Levant by possession of a complete lateral line, a deeply emarginate caudal fin, a narrow caudal peduncle, a suborbital groove in male individuals, a well-developed pelvic axillary lobe, and 5-7 dark-brown bars on the flank. Molecular data suggest that the new species is characterised by a minimum K2P distance of 3.8% to O. "seyhanicola" in the COI mtDNA barcode region.

Revision of the Garra species of the Hajar Mountains in Oman and the United Arab Emirates with the description of two new species (Teleostei: Cyprinidae)

The Garra species inhabiting the Hajar Mountains are revised and five species are recognised, two of which are newly species described herein. Garra barreimiae, from the United Arab Emirates (UAE) and Northern Oman, is distinguished from other Garra species in the Hajar Mountains by a strongly mottled flank pattern with individual or series of midlateral orange scales, a white dorsal-fin tip, an orange spot at the upper operculum, and more gill rakers on the lower limb of the first gill arch. Garra barreimiae shawkahensis is a synonym of G. barreimiae. Garra gallagheri, from the Wadi Bani Khalid drainage in Oman, is distinguished by flank-scale margins the same colour or slightly darker than the centre of the scales. Garra longipinnis, from the interior wadis in the Central Hajar Mountains in Oman, is distinguished by flank-scale margins being clearly darker than the centre of scales. The original description of G. longipinnis was based on a few individuals with very large fins, which are here considered aberrant. Garra shamal, new species, from the coastal drainages around Muscat in Oman, is distinguished by a strongly mottled flank pattern usually without orange midlateral scales, a white dorsal-fin tip, no orange spot at the upper operculum, and middle caudal-fin rays and membranes the same colour or slightly darker than the rest of the fins in colouration. Garra sharq, new species, from the Wadi Kabbah drainage and a few interior springs in Oman, is distinguished by a strongly mottled flank pattern with individual or series of orange midlateral scales, no orange spot at the upper opercle, and dorsal-fin tip and membranes between central caudal-fin rays the same colour as the rest of the fins. All five species are well differentiated genetically and form distinct mitochondrial clades with between 2.1 and 9.2% differences (p-distances) in the mitochondrial COI.

Garra roseae, a new species from the Makran region in southern Iran (Teleostei: Cyprinidae)

Garra roseae, new species, is described from the stream Tang-e-Sarhe in the Iranian Makran region. It is distinguished from its congeners in the Middle East by lacking barbels, having a small mental disc, 42-58 total scales along the lateral line, 24-30 scales along the predorsal midline, and 20-24 circumpeduncular scales. It is further characterised by having five diagnostic nucleotide substitutions and a minimum K2P distance of 5.39% to G. rossica and 5.49% to G. nudiventris in the mtDNA COI barcode region. Garra phryne from eastern Iran is considered to be a synonym of G. nudiventris.

Pseudophoxinus cilicicus, a new spring minnow from southern Anatolia (Teleostei: Leuciscidae)

Pseudophoxinus cilicicus, new species, is described from the Arsuz, Ceyhan and Seyhan river drainages in the Gulf of İskenderun. It is distinguished from other members of the Pseudophoxinus zeregi species group by having a complete lateral line with 38-45 + 2-3 scales, the lower lip usually slightly projecting beyond the tip of the upper lip, a prominent black stripe along the flank, and no black pigments below the lateral line. Pseudophoxinus cilicicus is distinguished from P. zekayi by a minimum K2P distance of 3.8% based on the mitochondrial DNA barcode region. Pseudophoxinus atropatenus and P. sojuchbulagi are returned to the genus Rutilus.

Paraschistura makranensis, a new loach from the Jegin River drainage in southern Iran with comments on P. ilamensis and P. pasatigris (Teleostei: Nemacheilidae)

Paraschistura makranensis, new species, is described from the Jegin River drainage in southern Iran. It is distinguished from its congeners in Iran by having a plain brown or slightly mottled colour pattern on the flanks, a very slender body with a relatively short head, a complete lateral line extending almost to the caudal-fin base, the caudal peduncle covered by scales, and a suborbital flap in males. Paraschistura makranensis is distinguished from P. bampurensis and P. hormuzensis, its closest relatives in our dataset, by an uncorrected-pairwise distance based on the COI data of 4.0 and 5.4%, respectively. We treat Paraschistura pasatigris as a synonym of P. ilamensis.

DNA barcode reference libraries for the monitoring of aquatic biota in Europe: Gap-analysis and recommendations for future work

Effective identification of species using short DNA fragments (DNA barcoding and DNA metabarcoding) requires reliable sequence reference libraries of known taxa. Both taxonomically comprehensive coverage and content quality are important for sufficient accuracy. For aquatic ecosystems in Europe, reliable barcode reference libraries are particularly important if molecular identification tools are to be implemented in biomonitoring and reports in the context of the EU Water Framework Directive (WFD) and the Marine Strategy Framework Directive (MSFD). We analysed gaps in the two most important reference databases, Barcode of Life Data Systems (BOLD) and NCBI GenBank, with a focus on the taxa most frequently used in WFD and MSFD. Our analyses show that coverage varies strongly among taxonomic groups, and among geographic regions. In general, groups that were actively targeted in barcode projects (e.g. fish, true bugs, caddisflies and vascular plants) are well represented in the barcode libraries, while others have fewer records (e.g. marine molluscs, ascidians, and freshwater diatoms). We also found that species monitored in several countries often are represented by barcodes in reference libraries, while species monitored in a single country frequently lack sequence records. A large proportion of species (up to 50%) in several taxonomic groups are only represented by private data in BOLD. Our results have implications for the future strategy to fill existing gaps in barcode libraries, especially if DNA metabarcoding is to be used in the monitoring of European aquatic biota under the WFD and MSFD. For example, missing species relevant to monitoring in multiple countries should be prioritized for future collaborative programs. We also discuss why a strategy for quality control and quality assurance of barcode reference libraries is needed and recommend future steps to ensure full utilisation of metabarcoding in aquatic biomonitoring.

Alburnus zagrosensis, a junior synonym of Alburnus sellal (Teleostei: Leuciscidae)

Morphometric, meristic and molecular (COI) characters of Alburnus zagrosensis, from the upper Karun River drainage in Iran, largely overlap or are identical with those of A. sellal, a species widely distributed in the Qweik River and the Persian Gulf basin, including the Karun River drainage. As no character states could be found to clearly distinguish these species, A. zagrosensis should be treated as a junior synonym of A. sellal.

Review of the Oxynoemacheilus tigris group with the description of two new species from the Euphrates drainage (Teleostei: Nemacheilidae)

The Oxynoemacheilus tigris species group is reviewed, resulting in the recognition of six species, of which two are described herein as new. Oxynoemacheilus tigris is known from the endorheic Qweik River and the Merziman River, which is a tributary of the western Euphrates. Oxynoemacheilus ercisianus is endemic to the endorheic Lake Van basin and O. hazarensis is endemic to Lake Hazar basin in the upper Tigris drainage. Oxynoemacheilus kaynaki is widespread in the Euphrates drainage. The two undescribed species occur in the Euphrates drainage. Oxynoemacheilus arsaniasus, new species, from the Murat River and the upper Karasu (Muş) River drainage, is distinguished from other species of the O. tigris group by having a bold, black, irregularly-shaped bar at the caudal-fin base, an incomplete lateral line and a scaleless body. Oxynoemacheilus muefiti, new species, from the upper Murat River drainage and a tributary to the Atatürk reservoir, is most similar to O. ercisianus, from which it is distinguished by a more slender body and a shallower dorsal adipose crest. According to our molecular data, the Qweik population of O. tigris is suspected to be introgressed by O. namiri from the Orontes drainage. Oxynoemacheilus erdali is identified as a synonym of O. bergianus as we were unable to find differences between the two species.

Testing the devil's impact on southern Baltic and North Sea basins whitefish (Coregonus spp.) diversity

Background

The diversity and phylogeny of whitefish of the genus Coregonus is complex, and includes many endemic species of high conservation concern. However, because of commercial importance of whitefish fisheries, stockings and translocations have occurred repeatedly, which challenges the identification of local populations as conservation units. This study analyses the phylogenetic relationships of 15 contemporary and two historical populations of lake-resident and anadromous whitefish (Coregonus spp.) from the southern Baltic and North Sea basins. We elucidated the complex history of Lake Schaal (northern Germany) whitefish, for which a local tale suggests that the devil threw whitefish from the Central European Lake Constance into this lake. Studies from the early twentieth century indeed suggested numerous stocking events for Lake Schaal from Lake Constance, from Estonian/Russian Lake Peipsi and from the anadromous whitefish of the Baltic Sea.

Results

Analyses of 13 microsatellite markers showed that Lake Constance whitefish are unrelated to any northern Germany whitefish population, including the contemporary whitefish population from Lake Schaal. Comparison with four historical specimens further showed that the native Lake Schaal whitefish (C. holsatus) vanished from the lake, but has survived as a non-native population in the north German Lake Drewitz. The whitefish currently occurring in Lake Schaal and three adjacent lakes are identified as C. maraenoides, introduced from Lake Peipsi. The contemporary anadromous whitefish populations from the Baltic (German and Finnish coast) and the German River Treene (North Sea basin, stocked from Danish River Vida) grouped together, but showed significant genetic differentiation. The 14 historical specimens of C. oxyrinchus from Rivers Rhine and Schelde were assigned to several contemporary whitefish populations, but among them only one specimen was assigned to the contemporary River Treene population. Therefore, we do not support the view that the whitefish from River Vida/Treene are identical with the historical C. oxyrinchus.

Conclusions

Our study demonstrates that lake and anadromous whitefish in the Baltic and North Sea basins reflect a complex phylogeography, which is further blurred by the effects of repeated stocking and translocations. To identify conservation units, the genetic identity of each population has to be scrutinized.

Electronic supplementary material

The online version of this article (10.1186/s12862-018-1339-2) contains supplementary material, which is available to authorized users.

Diversity of spined loaches from Asia Minor in a phylogenetic context (Teleostei: Cobitidae)

Accurate determination of species diversity in areas of high endemicity, particularly those lacking comprehensive systematic knowledge, represents a challenge for both taxonomists and conservationists. This need is particularly evident in areas greatly affected by anthropogenic disturbances such as the Eastern Mediterranean and its freshwater environments. To improve our knowledge of Eastern Mediterranean freshwater fishes, we phylogenetically studied Western Palearctic Cobitis species, focusing on those found in Turkey. Overall, our results provide a robust framework to assess the number of species of Cobitis. Phylogenetic reconstructions based on mitochondrial (cyt b) and nuclear (RAG1) sequences show seven major clades (Clades 1-7) grouping all Western Palearctic Cobitis species, except C. melanoleuca. In general, each major clade comprises Cobitis species that inhabit geographically close areas and have similar secondary sexual characters. Multiple divergent lineages were identified in our analyses, some of which were highly divergent such as the ones inhabiting Turkish freshwaters. Moreover, in some analyses, several of the identified lineages were incongruent with a priori defined species. Furthermore, our analyses identified eight potentially new candidate species, six that had been suggested in previous studies and two that are reported here for the first time. Our results reveal Turkey as the area with the greatest diversity of spined loaches in the Mediterranean.

Freshwater Megafauna: Flagships for Freshwater Biodiversity under Threat

Freshwater biodiversity is highly threatened and is decreasing more rapidly than its terrestrial or marine counterparts; however, freshwaters receive less attention and conservation investment than other ecosystems do. The diverse group of freshwater megafauna, including iconic species such as sturgeons, river dolphins, and turtles, could, if promoted, provide a valuable tool to raise awareness and funding for conservation. We found that freshwater megafauna inhabit every continent except Antarctica, with South America, Central Africa, and South and Southeast Asia being particularly species rich. Freshwater megafauna co-occur with up to 93% of mapped overall freshwater biodiversity. Fifty-eight percent of the 132 megafauna species included in the study are threatened, with 84% of their collective range falling outside of protected areas. Of all threatened freshwater species, 83% are found within the megafauna range, revealing the megafauna's capacity as flagship and umbrella species for fostering freshwater conservation.

<i>Oxynoemacheilus</i> <i>zarzianus</i>, a new loach from the Lesser Zab River drainage in Iraqi Kurdistan (Teleostei: Nemacheilidae)

Oxynoemacheilus zarzianus, new species, is described from the Lesser Zab River drainage, a tributary of the lower Tigris. It is distinguished from other Oxynoemacheilus species in the Tigris drainage by having a slightly emarginate caudal fin, no suborbital groove in males, a complete lateral line, the posterior process of the bony air-bladder capsule directed posteriorly, the flank and posterior part of back covered by scales, short barbels and a deep caudal peduncle. It is the fourth Oxynoemacheilus species known from the Lesser Zab drainage, where such loaches seem to be highly isolated in headwaters. Oxynoemacheilus species diversity in the Euphrates and Tigris drainage is exceptional high. Today 22 species are known from the entire Euphrates and Tigris drainage and 15 from the Tigris drainage alone.

Redescription of Garra elegans (Günther, 1868), a poorly known species from the Tigris River drainage (Teleostei: Cyprinidae)

Tylognathus elegans, from the lower Tigris River drainage in Iraq, was previously placed in Pseudogarra and Hemigrammocapoeta. Studies based on mitochondrial (COI) and nuclear molecular markers (Rhodopsin) place T. elegans in Garra. As the species is poorly known, it is redescribed here.

Eidinemacheilus proudlovei, a new subterranean loach from Iraqi Kurdistan (Teleostei; Nemacheilidae)

Eidinemacheilus proudlovei, new species, is described from subterranean waters in the Little Zab River drainage in Iraqi Kurdistan. After the discovery of E. smithi in 1976, E. proudlovei is the second troglomorphic nemacheilid loach found in the Middle East and the second species placed in Eidinemacheilus. Eidinemacheilus proudlovei is distinguished from E. smithi by having 8+8 or 8+7 branched caudal-fin rays, no adipose keel on the caudal peduncle, enlarged jaws and a fully developed head canal system. It furthers differs substantially in its DNA barcode (&gt;8% K2P distance) from all other nemacheilid loaches in the Middle East, Europe and Western India.

Squalius namak, a new chub from Lake Namak basin in Iran (Teleostei: Cyprinidae)

Squalius namak, new species, from the endorheic Lake Namak and Kavir basins in Iran, is distinguished from the species of the genus Squalius in the Persian Gulf and the southern Caspian Sea basins by having a wide and thick symphysial knob on the lower jaw, a convex posterior anal-fin margin, a bold, dark-grey or brown, roundish or crescent-shaped blotch at the posterior tip of each flank scale and orange caudal-, anal- and pelvic-fin rays in life. Squalius namak is also characterized by four fixed, diagnostic nucleotide substitutions in the mtDNA COI barcode region.

Garra sindhi, a new species from the Jebel Samhan Nature Reserve in Oman (Teleostei: Cyprinidae)

Garra sindhi, new species, is described from Wadi Andhur in the Dhofar province of the Sultanate of Oman. It is closely related to G. dunsirei and G. smarti, two other species from the same Omani province. It differs from these species by the following combination of characters: breast covered by scales, a shallow hump on back, eyes normally developed and 8-12 gill rakers on the lower limb of the first gill arch.

Eidinemacheilus, a new generic name for Noemacheilus smithi Greenwood (Teleostei; Nemacheilidae)

Eidinemacheilus, new genus, is described for the troglomorphic Noemacheilus smithi Greenwood. The sole species of the genus is endemic to an aquifer in the Karun River drainage in the Iranian Zagros Mountains. Eidinemacheilus smithi was identified as a species in Paracobitis as both genera share an elevated dorsal adipose crest, a character state being widespread in nemacheilid loaches. Eidinemacheilus is distinguished from all other genera of Nemacheilidae in the Middle East by having 7+7 branched caudal-fin rays, a strongly reduced head canal system, no pigmentation and no eyes. Eidinemacheilus smithi is also distinguished from other genera in the Middle East by a combination of the following character states: pelvic-fin origin behind of a vertical of the dorsal-fin origin, anus slightly in front of the anal-fin origin and no sexual dimorphism in the length of the paired fins. Eidinemacheilus, as a valid genus, is supported by the analysis of mitochondrial DNA data that shows no close affinity to Paracobitis or other nemacheilid genera from Europe, the Middle East and Western India.

Redescription of Gobio nigrescens from the Hari River drainage (Teleostei: Cyprinidae)

Gobio nigrescens, from the Hari River drainage, is redescribed. It represents a valid species distinguished from congeners in the adjacent Caspian and Aral Sea basins by a combination of characters: a naked breast, 16 circumpeduncular scales and 6-7 irregularly shaped, black or brown blotches on back behind dorsal-fin base.

Sasanidus, a new generic name for Noemacheilus kermanshahensis Bănărescu & Nalbant, with discussion of Ilamnemacheilus and Schistura (Teleostei; Nemacheilidae)

Sasanidus, new genus, is described for Noemacheilus kermanshahensis Bănărescu & Nalbant, endemic to the Karkheh and Karun drainages in Iran. Sasanidus kermanshahensis was initially identified as a species in Oxynoemacheilus, from which it is distinguished by the absence of an external sexual dimorphism (i.e. longer pectoral fin, and nuptial tubercles on fins, head and back in males). Sasanidus is distinguished from all other genera of Nemacheilidae in the Middle East by a combination of the following character states: pelvic-fin origin behind of a vertical of the dorsal-fin origin, anus about one eye diameter in front of the anal-fin origin, dorsal adipose keel absent, a high crest on the bony capsule of the swim bladder present and colour pattern marbled or mottled or with an irregularly shaped midlateral stripe. Ilamnemacheilus longipinnis was examined and no difference could be found between Ilamnemacheilus and Oxynoemacheilus. Therefore, Ilamnemacheilus is treated as a synonym of Oxynoemacheilus. COI barcode sequences from all nemacheilid loach genera occurring in the Middle East and western India are analysed jointly for the first time. The view that Schistura is a paraphyletic assemblage is supported by the clustering of DNA sequences from 45 specimens placed in at least 20 species in the genus Schistura analysed here.

Capoeta anamisensis, a new species from the Minab and Hasan Langhi River drainages in Iran (Teleostei: Cyprinidae)

Capoeta anamisensis, from the Minab and Hasal Langhi River drainages in southern Iran, belongs to the C. trutta species group. Capoeta anamisensis is distinguished from other species of the C. trutta species group by the combination of the following characters: flank silvery without black spots; 56-67 scales in total along the lateral series; 11-12 scales above the lateral line and 21-25 gill rakers. Capoeta anamisensis is also distinguished from all other congeners in the Persian Gulf basin by having four fixed, diagnostic nucleotide substitutions in the mtDNA COI barcode region and five fixed, diagnostic nucleotide substitutions in the mtDNA cyt b region. The type of Capoeta barroisi persica is identified as an aberrant individual of C. trutta and is considered as a synonym of that species.

Garra mondica, a new species from the Mond River drainage with remarks on the genus Garra from the Persian Gulf basin in Iran (Teleostei: Cyprinidae)

Garra mondica, new species, from the Mond River drainage in Iran is distinguished from its congeners by having 7½ branched dorsal-fin rays; the breast, belly and back in front of the dorsal-fin origin naked and 9+8 branched caudal-fin rays. Garra mondica is also distinguished from all other congeners in the Persian Gulf basin, except an unidentified species from the Kol River, by having two fixed, diagnostic nucleotide substitutions in the mtDNA COI barcode region. The identity of G. gymnothorax, a nominal species from the Karun River drainage, and G. crenulata, a nominal species from Central Iran, are discussed. Garra populations examined from the Karun have a unique mtDNA COI barcode sequence, but their diagnostic characters are not consistent with the description and syntypes of G. gymnothorax. G. crenulata is considered as a synonym of G. rufa. Two populations of Garra from the Kol River have a sequence of the COI barcode region very similar to G. mondica, but cannot be identified as G. mondica and their identity cannot be resolved here.

Cobitis avicennae, a new species of spined loach from the Tigris River drainage (Teleostei: Cobitidae)

Cobitis avicennae, new species, from the Karkheh and Karun sub-drainages in the Tigris catchment is distinguished from other Cobitis species in the Persian Gulf, Kor and the southern Caspian Sea basins by having a single lamina circularis in males, a small comma-shaped black spot on the upper caudal-fin base, 5½ branched anal-fin rays, 5-6 rows of dark spots on the dorsal and caudal fins, scales below the dorsal-fin base with a small focal zone and pigmentation zone Z4 with 12-17 large, partly fused blotches. It is also distinguished from other Cobitis species in the comparison group by six fixed, diagnostic nucleotide substitutions in the mtDNA COI barcode region.