Incomplete knowledge of biodiversity remains a stumbling block for conservation planning and even occurs within globally important Biodiversity Hotspots (BH). Although technical advances have boosted the power of molecular biodiversity assessments, the link between DNA sequences and species and the analytics to discriminate entities remain crucial. Here, we present an analysis of the first DNA barcode library for the freshwater fish fauna of the Mediterranean BH (526 spp.), with virtually complete species coverage (498 spp., 98% extant species). In order to build an identification system supporting conservation, we compared species determination by taxonomists to multiple clustering analyses of DNA barcodes for 3165 specimens. The congruence of barcode clusters with morphological determination was strongly dependent on the method of cluster delineation, but was highest with the general mixed Yule-coalescent (GMYC) model-based approach (83% of all species recovered as GMYC entity). Overall, genetic morphological discontinuities suggest the existence of up to 64 previously unrecognized candidate species. We found reduced identification accuracy when using the entire DNA-barcode database, compared with analyses on databases for individual river catchments. This scale effect has important implications for barcoding assessments and suggests that fairly simple identification pipelines provide sufficient resolution in local applications. We calculated Evolutionarily Distinct and Globally Endangered scores in order to identify candidate species for conservation priority and argue that the evolutionary content of barcode data can be used to detect priority species for future IUCN assessments. We show that large-scale barcoding inventories of complex biotas are feasible and contribute directly to the evaluation of conservation priorities.

Large African barbs of the genus Labeobarbus constitute a hexaploid lineage (2n = 150). This group is widely distributed in African freshwaters, and exhibits profound phenotypic variation that could be a prerequisite for adaptive radiation. Using morphological, molecular, and stable isotope analyses, we investigated whether an adaptive radiation has occurred in a riverine assemblage of the Labeobarbus gananensis complex. This complex is composed of six phenotypically distinct sympatric forms inhabiting the Genale River (Ethiopian highlands, East Africa) in the Juba and Wabe–Shebelle drainages (Indian Ocean basin). Of the six forms, five were divergent in their mouth morphology, corresponding to generalised, lipped, scraping (two forms), and large‐mouthed phenotypes. One form had no mouth specialisation, but differed from the others in body shape (short and deep body; short form). Stable isotope analysis revealed differences in 15N among these forms, representing different foraging strategies (omnivorous, scraping, and piscivorous). Phylogenetic analysis of two mitochondrial DNA markers confirmed the monophyly of L. gananensis, suggesting an intra‐riverine radiation. However, the Genale assemblage appears to have originated through a combination of allopatric and sympatric events. Some of the specialised forms within the Juba and Wabe–Shebelle drainage originated independently from the local generalised forms in three different river regions. Each of these cases could be considered as a small species flock composed of two or three sympatric forms. Our study shows that adaptive radiation in rivers can be enhanced by a combination of sympatric speciation and temporal geographic isolation, leading to local sympatric speciation followed by migration.

The genus Luciobarbus Heckel, 1843 is characterized by medium to large fish species occurring in large rivers and downstream zones with slow-moving waters. Remarkably also rheophilic Luciobarbus occur in Morocco, which are of small size and exhibit distinct morphological traits as well as different habitat requirements. These rheophilic species have traditionally been assigned to Luciobarbus nasus (Günther, 1874) and L. magniatlantis (Pellegrin, 1919), although some authors consider L. magniatlantis as a junior synonym of L. nasus. This lack of consensus on the taxonomy of rheophilic barbs is constrained by limited population studies that do not encompass their entire distribution range. Using molecular, morphometric, and osteological data we studied populations of rheophilic barbs of three drainage basins in which they are currently present: Tensift, Moulouya and Oum er Rbia. Our results clearly identified the rheophilic barbs of each basin as different species. The species Luciobarbus magniatlantis is a well-recognized species endemic to Tensift Basin. In contrast, the investigated populations from the Moulouya and Oum er Rbia basins could not be assigned to any previously described species. Consequently, we describe two new Luciobarbus species in the Moulouya and Oum er Rbia basins.

The genus Luciobarbus in Morocco presents high diversification, in contrast to the generally impoverished freshwater fish fauna from North Africa. Within Morocco the northern area is one of the least studied territories, due to both its historical background and the limited accessibility of many regions. Previous phylogenetic studies identified Luciobarbus populations that are morphologically and genetically differentiated, to the same extent as others already recognized as separate species. The aim of this work is to describe these populations as distinct species, based on morphological, meristic, and genetic traits.

Since the Cenozoic Era, the southern Iberian Peninsula has undergone a series of complex geological and climatic changes that have shaped the hydrographic configuration of the freshwater network, influencing the present‐day distribution of primary freshwater species and favoring a high level of local endemicity. The cyprinid species Luciobarbus sclateri (Günther, 1968) is an endemic species confined to the southern Iberian Peninsula and characterized by a complex evolutionary history. Previous studies linked the structure of L. sclateri populations to the effects of climate change during glaciations and were not able to explain the genetic discordance found between nuclear and mitochondrial markers. The results of this study show that the structure of L. sclateri populations is a reflection of diversification processes linked to the geological history of the region. Thus, we found three main mitochondrial phylogroups: the first one corresponding to small basins in southern Iberian Peninsula, a second one in eastern Iberian Peninsula, corresponding to Segura population, and a third one including the rest of the basins where the species is distributed. The southern group began diverging in the Pliocene as result of tectonic dynamics characterized by the emersion of the basins around the Strait of Gibraltar. The other two groups began diverging with the formation of the current Iberian hydrographic system during Pleistocene. So, the isolation of the hydrographic basins was the main factor driving intraspecific differentiation, followed by recent secondary contacts, admixture, and re‐isolation of the populations.

Aim: The current configuration of the Mediterranean Basin is the result of a complex geological history that promoted a drastic change of biological diversity, richness and distribution of freshwater organisms. Currently cyprinids of the genus Luciobarbus are the only representative of primary freshwater fishes widely distributed in the Mediterranean Basin, showing its highest diversity in the Western Mediterranean. Within this context, our objective was to explore the biogeographical patterns of the genus Luciobarbus in the context of the drastic geological changes during the Messinian. Location: Western Mediterranean, including southern Iberia and North Africa. Methods: Sampling covered the range of all known populations of Luciobarbus present in North Africa and southern Iberian Peninsula. Molecular data included mitochondrial and nuclear markers (mt-cyb and actinII). Time-calibrated phylogenies were inferred and a dispersal-extinction-cladogenesis model was used to reconstruct the biogeographical history. Results: Our results suggest that the two western lineages of Luciobarbus originated during the Messinian, one including most of the North African species from Morocco and western Algeria and another composed of Iberian, one Moroccan and one Algerian species.Main conclusion: During the Messinian, we found that two main events shaped the distribution of the western lineages of Luciobarbus. The first is associated with the end of the Messinian, which has previously been claimed to explain the difference between sister groups of freshwater fish fauna from both sides of the Gibraltar Strait.The second older and previously undetected event is associated with the existence of the last gateways connecting the Mediterranean Sea and the Atlantic Ocean.

Large African barbs of the genus Labeobarbus are widely distributed in African freshwaters, and exhibit profound phenotypic plasticity that could be a prerequisite for adaptive radiation. Using morphological, molecular, and stable isotope analyses, we investigated whether an adaptive radiation has occurred in a riverine assemblage of the L. gananensis complex. This complex is composed of six phenotypically distinct sympatric forms inhabiting the Genale River (Ethiopian highlands, East Africa). Of the six forms, five were divergent in their mouth morphology, corresponding to 'generalized', 'lipped', 'scraping' (two forms) and 'large-mouthed' phenotypes.Stable isotope analysis revealed differences in 15N and 13C among these forms, representing different foraging strategies (omnivorous, scraping and piscivorous). Phylogenetic analysis of two mtDNA markers confirmed the monophyly of L. gananensis, suggesting an intra-riverine radiation. However, the Genale assemblage appears to have originated through a combination of allopatric and sympatric events. Some of the specialized forms within this drainage originated independently from the local generalized forms in three different river regions within local 'miniflocks' composed of two to three sympatric forms. Our study shows that adaptive radiation in rivers can be enhanced by a combination of sympatric speciation and temporal geographic isolation, leading to local sympatric speciation followed by migration.

En los últimos años ha sido revisada la taxonomia de Barbus Cuvier and Cloquet, 1816 y como consecuencia de esta revisión algunas especies incluidas tradicionalmente en el género Barbus sensu lato han sido asignadas a otros géneros. En el Norte de África las especies del antiguo género Barbus han sido adscritas a los géneros Luciobarbus Heckel, 1843, Carasobarbus Karaman, 1971 y Enteromius Cope, 1867. Nosotros estudiamos las especies del antiguo género Barbus en la cuenca del río Moulouya en Marruecos a través de datos moleculares, morfométricos y osteológicos. Nuestros datos muestran claramente que las poblaciones de la cuenca del río Moulouya descritas como Barbus moulouyensis Pellegrin, 1924 pertenecen al género Carasobarbus y no al género Luciobarbus. Sin embargo, poblaciones del género Luciobarbus existen en la cuenca del río Moulouya y no pudieron ser asignadas a ninguna de las especies previamente descritas. En consecuencia nosotros describimos una nueva especie de la cuenca del río Moulouya.