The North Mediterranean Barbus lineage: phylogenetic hypotheses and taxonomic implications based on allozyme data

On the basis of distinct ecological and morphological characters, the European Barbus taxa have been clustered in two groups: a fluvio-lacustrine and a rheophilic or strictly riverine one. These two groups (or ecophenotypes) were recognized in different parts of Europe, and formed either a species assemblage ( Barbus barbus group) or a polytypic species ( Barbus meridionalis ). The hypothesis was that species of the same group belong to the same phylogenetic lineage (clade) and are the result of the same transcontinental colonization event. The analysis, using allozyme markers, of 10 taxa of the genus Barbus from France, Italy, Greece, the Czech Republic and Slovakia, showed that the taxa thought to belong to the fluvio-lacustrine and the rheophilic groups are not monophyletic. The results suggest that probably in each sub-region, the founding taxon has diverged independently to form species of two different ecophenotypes, one occupying the upstream rivers and the other the lowland rivers. Accordingly, Barbus species groups represent clusters of morphologically convergent taxa living in equivalent biotopes.     

Monogenic inheritance of trunk banding patterns in Barbus tetrazona

The Sumatra barb Barbus tetrazona exhibits two trunk banding patterns: a four-banded and a five-banded pattern characteristic of B. t. tetrazona and B. t. partipentazona , respectively. Segregation patterns in the progenies from 11 different matings suggest monogenic inheritance of trunk banding in this species.     

Karyological study of some cyprinid species from Ethiopia. The ploidy differences between large and small Barbus of Africa

Chromosome sets of nine species of Barbus and a species of Varicorhinus from Ethiopia were investigated. All large Barbus ( B. bynni, B. intermedius, B. ethiopicus ) and V. beso are shown to have 2N =150, whereas all small Barbus ( B. anema, B. kerstenii, B. paludinosus , and three unidentified (probably undescribed) species have 2N = 50. Based on the karyological data and on the published morphological data, an independent origin of small and large Barbus of Africa is suggested. The authors believe that large Barbus of Africa constitute a monophyletic group and that this group has no sister-group relationships with any of the small Barbus of Africa.     

Ecological and genetic differentiation of Barbus callensis populations in Tunisia

Enzyme electrophoresis on horizontal starch gel was carried out on 356 barbel individuals. The sampling comprised 278 individuals of the species Barbus callensis from 10 rivers in Tunisia. The other individuals belonged to reference species (outgroups) from France and Morocco. An ecological study was also carried out on Tunisian rivers. The results show a clear differentiation of the two samples from northwestern Tunisia, which was only partly correlated with ecological characteristics of the rivers they inhabit. There is no genetic cline, but rather a discontinuity between populations in the northwestern-most watershed and all the other Tunisian populations. This differentiation probably has a paleohistoric origin not only related to adaptation to ecological conditions but also to difficulties in colonizing the watersheds. The results do not indicate clearly a colonization direction for the genus Barbus in North Africa. Analysis of the Algerian populations would appear to be indispensable. Lastly, in contrast with the usual taxonomy, Morocco and Tunisia are populated by two closely related species, but B. callensis should remain the name of the Tunisian species, which was the first to be described in the small El Kebir basin, a river that flows from Tunisia to Algeria.     

New evidence of hexaploidy in' large' African Barbus with some considerations on the origin of hexaploidy

Three species of' large' African Barbus from the Republic of Guinea (West Africa), were characterized by the chromosome numbers (2N) of 148 (B. bynni occidentalis and B. wurtzi ) and 150 (B. petitjeani Daget, 1962). All these species have a karyotype which corresponds to the evolutionary hexaploid level. The karyotype of B. petitjeani is composed of chromosomes clearly grouped into morphologically homomorphic sextets which may document the origin of hexaploidy via an autopolyploidic event. Present findings extend the known distribution of evolutionary hexaploidy in' large' African Barbus to West Africa and show evidence of the pan-African distribution of this phenomenon.     

Polymorphism of white muscle myosin and parvalbumins in the genus Barbus (Teleostei: Cyprinidae)

Muscle proteins were investigated in two large European barbels, Barbus barbus and B. meridionalis , and in four small tropical barbels native to SE Asia: B. conchonius , B. tetrazona , B. sachsi and B. titteya . Polyacrylamide gel electrophoresis was used to analyse myosin heavy and light chains and parvalbumin isotypes from white trunk muscle. Each species could be biochemically identified. The myosin subunit and parvalbumin isotype patterns obtained for the two European barbels were similar. The Asian barbels, on the other hand, not only differed from the European species but displayed a greater diversity within their group. These biochemical results are largely in agreement with morphological and genetic data, but fail to substantiate suggested close relationships between Asian barbel species.     

Effect of river regulation on the life-history patterns of Barbus sclateri in the Segura river basin (south-east Spain)

The age structure, growth and reproduction of Barbus sclateri in a non-regulated section of the Segura River were similar to previously studied populations of undisturbed areas. Differences in the duration of the growth period or the reproductive cycle are considered evidence of the plasticity of the species as it adapts to different latitudes and local habitat characteristics. However, this population differed from one in a section with artificial water flow regulation. The non-regulated river population had a greater number of age groups, displayed a regular condition cycle, reached maturity earlier at lower ages and lengths and showed greater fecundity than the regulated river population. The mean lengths at age were longer in the regulated river population, possibly owing to the longer river section studied and/or to selective mortality of smaller specimens within a particular age group from the high water velocity when sluices are opened.     

Phylogeny and evolution of the genus Barbus in the Iberian Peninsula as revealed by allozyme electrophoresis

Variation of 14 enzyme systems encoded by 31 presumptive loci in different barbel species was studied using starch gel electrophoresis. Eighteen samples representing 11 Barbus tetraploid taxa were taken, including 10 populations from the Iberian Peninsula, six from other parts of western and southern Europe, one from northern Africa and one diploid species as outgroup from Asia Minor. The genetic analysis reassessed of the taxonomic status of the Iberian barbels into two distinct species groups. The first group included B. bocagei, B. comiza, B. graellsii, B. gulraonis, B. microcephalus , and B. sclateri , that aligned with B. callensis from northern Africa and with B. apoensis from Asia Minor; the other group included B. haasi and B. merldlonahs that was related to the European species, B. barbus, B. plebejus and B. peloponnesius . These groups are probably not monophyletic. It is suggested that the isolation of the Iberian Peninsula from Europe since the Oligocene-Miocene may explain the genetic affinities of the Iberian barbels with those of North African rather than with the European group.     

Feeding ecology of the Iberian cyprinid Barbus bocagei Steindachner, 1865 in a lowland river

Patterns of food resource utilization by Barbus bocagei in a lowland river in the central part of the Iberian Peninsula are presented and discussed. Focal points include feeding activity, diet composition and seasonal and ontogenetic diet shifts. Striking features of overall feeding pattern of barbel are its continuous feeding activity, bottom habits, high consumption of detritus and dipteran larvae and narrow diet breadth. Seasonal changes in food resource availability elicited changes in food utilization patterns, revealing a trend to more generalist feeding during spring. Barbel increase consumption of plant material and large prey during ontogeny, but overlap in prey resource utilization between size classes is high. The versatility of barbel foraging behaviour may be an important feature in its exploitation of Iberian lotic systems.     

Anthropogenic changes in the freshwater fish fauna of Italy, with reference to the central region and Barbus graellsii, a newly established alien species of Iberian origin

In a survey of the west-central Italian rivers Ombrone, Fiora, Albegna and Bruna, among established exotic species, the Iberian barbel Barbus graellsti was recorded in Italian fresh waters for the first time. Morphological identification was supported by comparison of cytochrome b sequences with those from related barbel species. Other exotics of particular note were Barbus barbus, Pseudorasbora parva and Leuciscus cephalus , together with the Padano-Venetian Chondrostoma genei and Padogobius bonelli. Native species still present included Leuciscus lucumonis, Telestes muticellus, Rutilus rubilio and Padogobius nigricans , but were now more restricted to upper reaches and smaller watercourses. The deleterious effect of alien species on native forms is discussed with particular reference to probable competition between C. genei and L. lucumonis , and between the two gobies. The checklist of species introduced to the fresh waters of Italy is now updated to 34. For the Italian freshwater fish fauna in general, the conservation status of three native species ( Acipenser naccari, Salmo marmoratus and Knipowitschia punctatissima ) has been improved but five species are believed to be at risk ( Salmo carpio, L. lucumonis, Scardinius scardafa, Gobio benacensis and P. nigricans ) and four anadromous species ( Petromyzon marinus, Lampetra fluviatilis, Acipenser sturio and Huso huso ) no longer breed in Italian fresh waters. The processes of change in the composition of the Italian freshwater fish fauna as a whole may be summarized as successively 'padanization', 'danubization' and now 'globalization'.     

Genetic relationships between Marico barb (Barbus motebensis, Steindacher 1894), Redtail barb (B. gurneyi, Günther 1868) and Amatola barb (B. amatolicus, Skelton 1990)

Starch gel-electrophoresis was used to assess genetic differences between two populations of Barbus motebensis and two other taxonomic related and morphologically similar barb species. Ten of the 29 protein coding loci studied were polymorphic. In spite of the small bio-metric and meristic differences between the species studied, the extent of genetic differences suggests four distinct species. The evidence in support of a new barb species in the Ohrigstad River further adds to the current conservation importance of the rivers of the eastern Transvaal escarpment as a ‘hotspot’ for endemic fish species.     

Phylogeography of the barbel (Barbus barbus) assessed by mitochondrial DNA variation

Using the phylogeographic framework, we assessed the DNA sequence variation at the mitochondrial cytochrome b gene across the distribution range of the barbel Barbus barbus, a widely distributed European cyprinid. Reciprocal monophyly of non-Mediterranean European and Balkan/Anatolian populations is taken as evidence for a long-term barrier to gene flow, and interpreted as a consequence of survival of the species in two separate refugia during several later glacial cycles. Lack of profound genealogical divergence across Europe from western France to the northwestern Black Sea basin is consistent with recent colonization of this area from a single glacial refuge, which was probably located in the Danube River basin. This may have occurred in two steps: into the Western European river basins during the last interglacial, and throughout the Central European river basins after the last glacial. The populations from the Balkans and Anatolia apparently did not contribute mitochondrial DNA to the post-Pleistocene colonization of non-Mediterranean Europe. Lack of detectable variation within the Balkans/Anatolia is attributed mainly to recent expansion throughout these regions, facilitated by the freshwater conditions and seashore regression in the Black Sea during the Late Pleistocene and Early Holocene.     

Dry-season spawning in a cyprinid fish of southern India

Synopsis A population of the S. Indian cyprinid fishBarbus melanampyx was sampled monthly through 24 months. Seasonal cycles of the gonado-somatic index (GSI), ovarian stages, male breeding tubercles, spawning behaviour and population structure were assessed. These fish breed strictly seasonally during the main dry period: December/January through April. Comparison with other Barbus species of the same general region led to the conclusion that the patterns of reproductive investment ofB. melanampyx are similar to those of perennial species, and different from those of wet-season spawners. The reasons for this rather unexpected result were found in the more constant conditions prevailing during a dry season as compared to the monsoon. It was argued thatB. melanampyx and the species spawning perennially are in effect small-brood spawners, rather than partial spawners.     

Haplotype diversity and phylogenetic relationships among the Iberian barbels (Barbus,Cyprinidae) reveal two evolutionary lineages

The phylogenetic relationships and haplotype diversity of all Iberian barbels were examined by analyzing the complete mitochondrial cytochrome b gene sequence (1141 bp) of 72 specimens from 59 Iberian localities. Phylogenetic findings demonstrated a clear distinction between two mitochondrial lineages and confirmed the existence of two previously considered subgenera: Barbus and Luciobarbus: The first subgenus, Barbus, is represented on the Iberian Peninsula by Barbus haasi and Barbus meridionalis. The second subgenus, Luciobarbus, includes the remaining endemic Iberian species: Barbus comizo, Barbus bocagei, Barbus microcephalus, Barbus sclateri, Barbus guiraonis, and Barbus graellsii. Mean haplotype divergence between these subgenera was 10.40%, providing evidence of a clear subdivision within the Iberian barbels. Our results conflict with those reported in a recent study, based on 307 cytochrome b base pairs, that failed to identify any division within the genus Barbus in the Iberian Peninsula. The inclusion of nine further species belonging to this genus (used as outgroups) allowed us to establish a closer relationship of the Iberian species of the subgenus Barbus with other European taxa than with the Iberian Luciobarbus, which was found to cluster with North African, Caucasian, and Greek species. At the population level, no biogeographic structure was shown by specimens of each species (only 5.98% of the variation was attributable to differences among populations of each species). Given the discrete amount of divergence found among the Luciobarbus species, the formation of current hydrographic basins during the Plio-Pleistocene seems to have played a major role in their isolation and evolution.     

Identification of Spanish barbel species using the RAPD technique

The RAPD-PCR technique was employed to identify three endemic Spanish species of Barbus: Barbus bocagei, B. graellsii and B. sclateri , that present very similar morphologies. Using seven primers, six diagnostic bands were found in B. bocagei , 11 in B. graellsii and nine in B. sclateri . Cluster analysis of the genetic similarity values obtained from RAPD data indicated that the species B. bocagei and B. graellsii are more related to each other than to B. sclateri .     

Molecular identification (RAPD) of the eight species of the genus Barbus (Cyprinidae) in the Iberian Peninsula

Random amplified polymorphic DNA (RAPD) analysis has been used to identify the eight Barbus species of the Iberian Peninsula, whose morphological differentiation is difficult. Ten random primers were employed to generate RAPD markers. Different RAPD profiles were observed for the different species. Four species-specific markers were found in B. bocagei , seven in B. comizo , five in B. graellsii , three in B. guiraonis , eight in B. haasi , 13 in B. meridionalis , four in B. microcephalus and four in B. sclateri. Evidence is presented that RAPD markers constitute useful tools for accurate taxonomic identification of Spanish barbels which is one of the first prerequisites in effective conservation programmes.     

The reproductive strategy of a barb, Barbus anoplus (Pisces: Cyprinidae), colonizing a man-made lake in South Africa

The barb, Barbus anoplus . successfully colonized the marginal habitat of the newly created Lake le Roux on the Orange River system in South Africa. Early maturity and a high reproductive effort facilitated this success. It is suggested that the reproductive strategy which evolved in a seasonally fluctuating riverine environment was advantageous to a species colonizing a newly created man-made lake.     

Early development of the cephalic skeleton of Barbus barbus (Teleostei, Cyprinidae)

The inception, and development of the cephalic skeleton of Barbus barbus from hatching to 24 days passes through periods of fast and slow growth; these rates are not the same in different parts of the skull. Trabeculae, parachordal plates, Meckelian cartilages and hyposymplectics are present at hatching. Then the cartilaginous floor of the neurocranium develops, the pars quadrata, the hyoid bars and branchial arches elements appear shortly before the first movable dermal bones, the dentaries, maxillae and opercles. The first bone of the braincase to appear is the parasphenoid; other bones develop subsequently and at the same time: the angular, quadrate, interopercle and fifth ceratobranchial. Later the splanchnocranium continues to develop at a relatively fast rate while the neurocranium shows little growth. The braincase does not begin to close before the 24th day, nor do the first bones of the skull roof appear, while the bucco-pharyngeal apparatus is complete, having the adult shape. The early constitution of the latter structures seems to be linked with the mechanical demands of biological functions such as breathing and feeding.