Development of the cranium in the large African hexaploid barb Labeobarbus (=Barbus) intermedius (Cyprinidae; Teleostei)

Developmental information on the structure and composition of the cartilaginous and bony skull in the large African barb Labeobarbus (=Barbus) intermedius (Teleostei; Cyprinidae) is provided. Sequences of cartilages and bones appearance from a large series of cleared and Alizarin red- and Alcian blue-stained laboratory-reared specimens ranging from prehatching larvae to juvenile stages are described. Comparisons of cranial development are made among cyprinids: L. intermedius, Danio rerio, Barbus barbus, and Cyprinus carpio.     

Molecular phylogeny of the subfamily Schizothoracinae (Teleostei: Cypriniformes: Cyprinidae) inferred from complete mitochondrial genomes

The schizothoracine fishes, members of the Teleost order Cypriniformes, are one of the most diverse group of cyprinids in the Qinghai–Tibetan Plateau and surrounding regions. However, taxonomy and phylogeny of these species remain unclear. In this study, we determined the complete mitochondrial genome of Schizopygopsis malacanthus. We also used the newly obtained sequence, together with 31 published schizothoracine mitochondrial genomes that represent eight schizothoracine genera and six outgroup taxa to reconstruct the phylogenetic relationships of the subfamily Schizothoracinae by different partitioned maximum likelihood and partitioned Bayesian inference at nucleotide and amino acid levels. The schizothoracine fishes sampled form a strongly supported monophyletic group that is the sister taxon to Barbus barbus. A sister group relationship between the primitive schizothoracine group and the specialized schizothoracine group + the highly specialized schizothoracine group was supported. Moreover, members of the specialized schizothoracine group and the genera Schizothorax, Schizopygopsis, and Gymnocypris were found to be paraphyletic.     

A new cavefish of Sinocyclocheilus (Teleostei: Cypriniformes: Cyprinidae) from the Nanpanjiang River in Guizhou,China

A new species, Sinocyclocheilus xingyiensis, is described based on specimens collected from a karst cave in Guizhou Province, China. The authors used an integrated taxonomic approach, including morphological and molecular data, to identify the new species as a member of the Sinocyclocheilu angularis group, and it can be distinguished from all other members of this group by a combination of the following features: two pairs of long barbels and long pectoral fins, 42–46 lateral-line scales, 7 (13–14) on outer (inner) side of the first gill arch and 35 (14–15 + 4 + 16 − 17) vertebrae. Phylogenetic analyses based on the cytochrome b (cyt b) gene fragment suggest that S. xingyiensis is a sister lineage to Sinocyclocheilus flexuosdorsalis. The genetic distance (Kimura 2-parameter) between the S. xingyiensis and S. angularis groups of Sinocyclocheilus species based on cyt b gene fragment ranged from 1.2% to 15.4%.     

Homologies of the branchial arch muscles in Zacco platypus (Teleostei: Cypriniformes: Cyprinidae): Evidence from innervation pattern

Homologies of the branchial arch muscles in the cyprinid Zacco platypus are assessed based on their innervation. Muscles serving the first gill arch are innervated by branches of the glossopharyngeal (IX) nerve and those serving other arches by the vagal (X) nerve. Absence of the levator posterior is confirmed. Five pairs of muscles originating from the cranium and inserted onto the specialized 5th ceratobranchial, all unique to cyprinids, are innervated by the 4th branchial trunks of X, indicating that all pairs are derivatives of the sphincter oesophagi, involving reorganization from intrinsic to extrinsic elements. Homologies of some ventral branchial muscles are also discussed and the criteria for homology improved by clarifying the innervation pattern. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.     

Spawning migrations of the endemic Labeobarbus (Cyprinidae, Teleostei) species of Lake Tana, Ethiopia: status and threats

The reproductive biology of the only known intact species flock of large cyprinids, the 16 Labeobarbus species of Lake Tana (Ethiopia), has been extensively studied for the past two decades. Seven species of Labeobarbus are known to migrate >50 km upstream into tributary rivers for spawning during the rainy season (July to October), whereas eight other species are absent from these rivers and probably developed a new strategy of lacustrine spawning (macro-spatial segregation). One species (L. intermedius) probably spawns in the lake as well as in the rivers. Between the early 1990s and 2000s, the riverine spawners showed a decline of 75% in both biomass and number in both fishery independent surveys and in commercial catches. Reproductive migration makes fishes vulnerable to fisheries and other threats like habitat modifications. Lacustrine spawners are probably more resilient as they are not known to form spawning aggregations that can easily be exploited by fishermen. In addition, upstream rivers and catchments around Lake Tana are highly degraded by erosion and recently subjected to intensive habitat modification for irrigation and hydroelectric power generation. This article reviews results of field studies on the Labeobarbus spawning migration from Lake Tana to spawning rivers, giving emphasis on segregation and homing. It also summarizes existing and emerging threats which form potential causes for the decline of the migratory Labeobarbus species. Knowledge gaps on the reproductive biology are identified for further investigation.     

Association between Labeobarbus spp. (Teleostei: Cyprinidae) and environmental variables in the Luhoho basin (Eastern Congo River basin; DRC)

The African cyprinid genus Labeobarbus is characterized by a high polymorphism in mouth morphology. The association between four species of this genus (two chiselmouths, one rubberlip with a well-developed fleshy mental lobe on the lower jaw, i.e., a fleshy appendage on the chin, and one usually with a poorly developed one) and 26 environmental variables was investigated in four affluents of the Luhoho River in the Albertine Highlands of the Upper Congo basin. A combination of univariate and multivariate analyses suggested that differences exist in habitat composition at localities where different Labeobarbus species were reported, and within different mouth phenotypes. The association of L. longidorsalis with the presence of cobbles and pebbles and of L. brauni with the presence of boulders suggests that the occurrence of chiselmouths phenotype is associated with stony habitats, whereas phenotypes with a mental lobe, i.e., Labeobarbus longifilis and L. paucisquamatus, mostly occupy habitats without stones. Differences in the distribution between these two species appear to be linked to physico-chemical parameters such as electrical conductivity and water temperature rather than substrate type. The findings of this study are relevant for developing guidelines that aim effective local preservation and conservation of these Labeobarbus species.     

滇池金线鲃形态度量学分析(Cypriniformes:Cyprinidae)

运用多变量形态度量学和框架结构形态学的方法,测量了采自滇池流域6个不同地点的149尾滇池金线鲃（Sinocyclocheilus grahami）的标本。应用多变量形态度量学分析,选择了20个框架结构性状和19个常规性状,进行主成成分分析。主成成分分析结果的散布图显示,6个不同地点的标本聚在一起没有分开,表明滇池金线鲃的各居群之间在可数性状和可量性状上均未表现出明显的差异,说明滇池金线鲃在形态上还未发生明显的种下分化。     

Asymmetry of the behavioral response in roach Rutilus rutilus (L.) (Teleostei: Cyprinidae) to a new object

The young roach Rutilus rutilus (L.) (Cyprinidae) displays lateralized behavior when facing a barrier through which a simulated bigger fish was visible. The asymmetry consists in a significant tendency to detour a barrier rightwards in the presence of a dummy fish. However, asymmetry is insignificant without the model. A comparison with the available literature shows that the roach has the same direction of this lateral bias as some other shoaling cyprinid fishes, which also preferentially turn to the right in the presence of a dummy fish. This seems to be a characteristic of cyprinids, as opposed to species of some other families displaying a leftward bias or a lack of asymmetry. The results of the study testify to the hypothesis that behavioral lateralization is associated with the taxonomic status of fishes. Currently, it is unclear whether the asymmetry found in roach in a detour test is due to the preferential use of the lateral fields of the right and left eyes as in some other fishes, or if it is a result of motor lateralization, which becomes evident in the presence of an unfamiliar and potentially dangerous object.     

Phylogeny of the gudgeons (Teleostei: Cyprinidae: Gobioninae)

The members of the cyprinid subfamily Gobioninae, commonly called gudgeons, form one of the most well-established assemblages in the family Cyprinidae. The subfamily is a species-rich group of fishes, these fishes display diverse life histories, appearances, and behavior. The phylogenetic relationships of Gobioninae are examined using sequence data from four loci: cytochrome b, cytochrome c oxidase I, opsin, and recombination activating gene 1. This investigation produced a data matrix of 4114 bp for 162 taxa that was analyzed using parsimony, maximum likelihood, and Bayesian inference methods. The phylogenies our analyses recovered corroborate recent studies on the group. The subfamily Gobioninae is monophyletic and composed of three major lineages. We find evidence for a Hemibarbus-Squalidus group, and the tribes Gobionini and Sarcocheilichthyini, with the Hemibarbus-Squalidus group sister to a clade of Gobionini-Sarcocheilichthyini. The Hemibarbus-Squalidus group includes those two genera; the tribe Sarcocheilichthyini includes Coreius, Coreoleuciscus, Gnathopogon, Gobiocypris, Ladislavia, Paracanthobrama, Pseudorasbora, Pseudopungtungia, Pungtungia, Rhinogobio, and Sarcocheilichthys; the tribe Gobionini includes Abbottina, Biwia, Gobio, Gobiobotia, Huigobio, Microphysogobio, Platysmacheilus, Pseudogobio, Romanogobio, Saurogobio, and Xenophysogobio. The monotypic Acanthogobio is placed into the synonymy of Gobio. We tentatively assign Belligobio to the Hemibarbus-Squalidus group and Mesogobio to Gobionini; Paraleucogobio and Parasqualidus remain incertae sedis. Based on the topologies presented, the evolution of swim bladder specializations, a distinctive feature among cyprinids, has occurred more than once within the subfamily.     

Vertebral Dimensions in the Genus Carasobarbus (Teleostei: Cyprinidae)

Journal of Ichthyology - The morphological study of the axial skeleton of the nine species of the genus Carasobarbus Karaman, 1971 enabled to confirm the division of this bony structure into five...     

广西南宁渐新世基于咽齿的鲤亚科一新属

记述了产自广西南宁盆地渐新世早—中期的鲤科鲤亚科一新属种——伍氏南宁鲤(+Nanningocyprinus wui gen.et sp.nov).化石材料包括一些咽喉骨和咽齿.这些咽喉骨和咽齿的以下特征组合明显不同于其他鲤科鱼类:齿式-3·2·1,主行第一枚咽齿大小是第二枚的3～4倍,第二枚咽齿及第二行第一枚咽齿咀嚼面上各仅有一条沟纹,咽骨前角很发育.该属种的发现进一步证明鲤亚科是鲤科中较早的分支,中国南方很有可能是鲤亚科的起源和分化中心.     

Phylogenetic analysis of the genus Rasbora (Teleostei: Cyprinidae)

Liao, T. Y., Kullander, S. O. & Fang, F. (2009). Phylogenetic analysis of the genus Rasbora (Teleostei: Cyprinidae).—Zoologica Scripta, 39, 155–176. A phylogenetic analysis was conducted based on 35 cyprinid taxa, including 29 species of Rasbora, and 41 morphological characters. A strict consensus tree from four equally parsimonious trees recovered rasborins as a monophyletic group characterized by (i) presence of dark supra‐anal pigment and subpeduncular streak, (ii) 5–6 branched anal‐fin rays, (iii) dorsal‐fin insertion 1–3 scales behind pelvic‐fin insertion, (iv) lateral process of second vertebra more or less straight, (v) 1–5 more abdominal than caudal vertebrae, (vi) absence of foramen in anterior wall of horizontal limb of the cleithrum, (vii) presence of rasborin process on epibranchial 4, and (viii) interhyal well ossified. Rasbora sensu stricto can be distinguished from all other rasborin genera by the presence of an opercular canal. Four new genera, viz. Brevibora, n. gen., Kottelatia, n, gen., Rasbosoma, n. gen. and Trigonopoma, n. gen., are recognized and described.     

Body shape evolution among ploidy levels of the Squalius alburnoides hybrid complex (Teleostei,Cyprinidae)

Hybridization, ploidy level and genomic constitution may be important to respond to different environments, by producing different phenotypes and thus reducing competitive interaction. Through geometric morphometrics, we examined variation in body size and shape among biotypes of the Squalius alburnoides hybrid complex and their sperm donor (Squalius carolitertii). Results showed that S. carolitertii is significantly larger in size than the biotypes of the complex. No significant relationship was observed between ploidy and body size among S. alburnoides biotypes. Significant variation in body shape was found between S. carolitertii and S. alburnoides, and between tetraploids and the other biotypes. These differences in biotypes may reduce resource competition, highlighting the potential importance of resource availability favouring one biotype over another. In S. alburnoides, the adaptation to different trophic niches through modification of trophic morphology, body shapes, and feeding behaviour, may result from an increase in ploidy and genomic constitution. This adaptation may account also for the formation and maintenance of this nonsexual complex.     

Molecular phylogeny of the cyprinid tribe Labeonini (Teleostei: Cypriniformes)

The cyprinid tribe Labeonini (sensuRainboth, 1991) is a large group of freshwater fishes containing around 40 genera and 400 species. They are characterized by an amazing diversity of modifications to their lips and associated structures. In this study, a total of 34 genera and 142 species of putative members of this tribe, which represent most of the generic diversity and more than one third of the species diversity of the group, were sampled and sequenced for four nuclear genes and five mitochondrial genes (totaling 9465bp). Phylogenetic relationships and subdivision of this tribe were investigated and the placement and status of most genera are discussed. Partitioned maximum likelihood analyses were performed based on the nuclear dataset, mitochondrial dataset, combined dataset, and the dataset for each nuclear gene. Inclusion of the genera Paracrossochilus, Barbichthys, Thynnichthys, and Linichthys in the Labeonini was either confirmed or proposed for the first time. None of the genera Labeo, Garra, Bangana, Cirrhinus, and Crossocheilus are monophyletic. Taxonomic revisions of some genera were made: the generic names Gymnostomus Heckel, 1843, Ageneiogarra Garman, 1912 and Gonorhynchus McClelland, 1839 were revalidated; Akrokolioplax Zhang and Kottelat, 2006 becomes a junior synonym of Gonorhynchus; the species Osteochilus nashii was found to be a member of the barbin genus Osteochilichthys. Five historical hypotheses on the classification of the Labeonini were tested and rejected. We proposed to subdivide the tribe, which is strongly supported as monophyletic, into four subtribes: Labeoina, Garraina, Osteochilina, and Semilabeoina. The taxa included in each subtribe were listed and those taxa that need taxonomic revision were discussed.     

Masculinization mechanism of hybrids in bitterlings (Teleostei: Cyprinidae)

The sex ratio of bitterling hybrids (subfamily: Acheilognathinae) is often likely to be biased toward males. Artificial hybridization was carried out in 10 species of bitterlings (three genera) in order to elucidate the masculinization mechanism of hybrids. Tanakia himantegus never produced viable F1 hybrids with other species, while hybrids of most other species were viable. In terms of sex ratio and fertility, hybrids were clearly divided into two groups: congeneric Tanakia hybrids and others. Both male and female congeneric Tanakia hybrids were fertile. The sex ratio was nearly 1:1 in all groups of Tanakia hybrids. Except for the congeneric Tanakia hybrids, sterile males appeared predominantly in groups of hybrids in which females were very rare but remained fertile. Sterile intersexes were also observed in five hybrid groups: T. lanceolata (female) x Acheilognathus cyanostigma (male), Rhodeus uyekii (female) x T. lanceolata (male), A. rhombeus (female) x T. lanceolata (male), A. rhombeus (female) x T. limbata (male), and A. tabira tabira (female) x A. cyanostigma (male). In the development of male-predominant hybrids, although hybrid and control (parental species) hatching and survival rates do not differ, no females appeared in hybrids, contrary to the controls. Taking the female heterogametic sex-determining system (ZW) and the phylogenetic relationship of bitterlings into consideration, the masculinization mechanism of hybrids in bitterlings can be explained by the interaction of two sex chromosomes, derived from each parental species. The basic genetic sex in bitterlings is male (ZZ) and the derivative is female (ZW). When parental species are related, the sex phenotype of hybrids coincides with the genetic sex. However, when the parental species differ, the sex phenotype of the ZW genotype is reversed to become male by an abnormal interaction between the Z and W chromosomes. The rare appearance of females and intersexes in male-predominant hybrids might be due to complete or partial functional expression of the W chromosome.     

Low genetic differentiation among morphologically distinct Labeobarbus species (Teleostei: Cyprinidae) in the Lake Victoria and Albertine basins,Uganda: insights from mitochondrial DNA

Labeobarbus altianalis and L. bynni bynni are hexaploid cyprinid fishes in the genus Labeobarbus. In the Great Lakes region of Africa, these two large-bodied barbs exhibit considerable morphological variations. Their intraspecific classification, currently based on geographical distribution and morphological variation, is of limited application due to the overlapping nature of the water systems. Patterns of genetic variation in the Albertine and Victoria drainage basins in Uganda were assessed using mitochondrial sequences of the control region (470 basepairs) and the cytochrome b gene (627 basepairs). At the control region 36 distinct haplotypes were observed in a total of 177 individuals. Relatively low overall nucleotide diversity (π = 0.010) was observed. Hierarchical analysis of the molecular variance revealed significant differentiation between populations in the total sample (F _ST = 0.172, p < 0.001), among populations within each basin (F _SC = 0.047, p < 0.001), but no significant subdivision among basins (F _CT = 0.131, p > 0.05). Phylogenetic analysis of the control region haplotypes resulted in a star-shaped phylogeny, with no clusters that reflect current taxonomic designation, morphotypes or basins. Phylogenetic analysis of cytochrome b gene sequences resulted in a tree topology similar to that observed for the control region. Thus the morphological characteristics separating the two species are intraspecific variation and the whole sample probably belongs to the same species.     

Development of the pharyngeal arch skeleton in Catostomus commersonii (Teleostei: Cypriniformes)

Skeletal elements of the gill arches of adult cypriniform fishes vary widely in number, size, and shape and are important characters in morphologically based phylogenetic studies. Understanding the developmental basis for this variation is thus phylogenetically significant but also important in relation to the many developmental genetic and molecularly based studies of the early developing and hence experimentally tractable gill arches in the zebrafish, a cyprinid cypriniform. We describe the sequence of the chondrification and ossification of the pharyngeal arches and associated dermal bones from Catostomus commersonii (Catostomidae, Cypriniformes) and make selected comparisons to other similarly described pharyngeal arches. We noted shared spatial trends in arch development including the formation of ventral cartilages before dorsal and anterior cartilages before posterior. Qualitatively variable gill arch elements in Cypriniformes including pharyngobranchial 1, pharyngobranchial 4, and the sublingual are the last such elements to chondrify in C. commersonii. We show that the sublingual bone in C. commersonii has two cartilaginous precursors that fuse and ossify to form the single bone in adults. This indicates homology of the sublingual in catostomids to the two sublingual bones in the adults of cobitids and balitorids. Intriguing patterns of fusion and segmentation of the cartilages in the pharyngeal arches were discovered. These include the individuation of the basihyal and anterior copula through segmentation of a single cartilage rod, fusion of cartilaginous basibranchials 4 and 5, and fusion of hypobranchial 4 with ceratobranchial 4. Such “fluidity” in cartilage patterning may be widespread in fishes and requires further comparative developmental studies. J. Morphol., 2009. © 2008 Wiley‐Liss, Inc.     

Threatened fishes of the world: Cyprinus micristius Regan 1906 (Cypriniformes: Cyprinidae)

Conservation status, identification, distribution, abundance, habitat and ecology, conservation actions and recommendations of a endemic cyprinid fish, Cyprinus micristius were introduced based on data and knowledge from a GEF project in Lake Dianchi, Yunnan, China.