A Maeotian (Late Miocene) freshwater fish-fauna from Romania

Isolated pharyngeal teeth, pectoral, dorsal and suborbital fish spines were unearthed in a new outcrop located on the right bank of the Prut River, at F?lciu, Romania. They document Late Miocene aquatic ecosystems of the Dacian basin. Seven taxa were identified and described, six of them belonging to the order Cypriniformes and one to Siluriformes. The Cobitidae is here firstly reported in the fossil record of Romania. All the fish teeth and skeletal remains are from representatives marking shallow water. The fossils were probably buried into sediments accumulated near the mouth of a rather fast-flowing river that drained into a brackish body of water, part of the Dacian basin. The composition of the fauna is similar to the coeval ones from the North (Ukraine and Republic of Moldova) and from the South (Turkey) of the Black Sea basin.     

Miniatures,morphology and molecules: Paedocypris and its phylogenetic position (Teleostei,Cypriniformes)

We review the morphological and molecular evidence that Mayden & Chen recently used to infer that the developmentally truncated fish genus Paedocypris is not a member of the teleost order Cypriniformes or carp‐like fishes, but is ‘the basal sister group to all Cypriniformes’. This hypothesis contradicts several previous studies that used molecular sequence data or morphological characters. A review of the morphological characters that Mayden & Chen discussed and mapped onto their ‘simplified tree’ shows that these, analysed alone, rather support a close relationship of the cyprinids Sundadanio, Danionella, and Paedocypris. We also present four additional analyses of morphological data, which all contradict Mayden & Chen's result. Despite its highly reductive skeleton, posing a serious problem when analysing its phylogenetic position with skeletal characters, the presence in Paedocypris of the basioccipital masticatory plate is compelling evidence that it is a member of the Cyprinoidei (Cyprinidae plus Psilorhynchidae). Our reanalysis and exploration of their molecular sequence data shows that only a single gene, EGR3, of the six nuclear genes analysed by Mayden & Chen, is responsible for the position of Paedocypris as ‘the basal sister group to all Cypriniformes’. Three independent methods to visualize and analyse phylogenetic signal and conflict of data sets (phylogenetic networks, splits analysis methods or SAMS, and site‐wise likelihood analyses) reveal a high level of character conflict and noise in Mayden & Chen's data set. The ‘basal’ position of Paedocypris seems to be the outcome of the interplay of two long‐branch effects. We apply the same analytical methods to the data set from Rüber et al.'s molecular analysis of the phylogenetic position of Paedocypris and discuss our findings. We conclude that none of the molecular data sets compiled to date can establish the phylogenetic position of Paedocypris with confidence. Morphological data suggest that Paedocypris and Danionella are sister genera, and that their closest relative is Sundadanio, although the position of these three miniatures among cyprinoids is still unclear. © 2014 The Linnean Society of London     

New primers for amplifying and sequencing the mitochondrial ND4/ND5 gene region of the Cypriniformes (Actinopterygii: Ostariophysi)

We provide 15 new primers for amplifying and sequencing the mitochondrial ND4/ND5 gene region of the Cypriniformes in an attempt to resolve relationships of this diverse group of freshwater fishes with extensive taxonomic sampling. Sequences from this region have the following desirable characteristics for phylogenetic analyses, some of which are lacking from the more commonly used cyt b and 12S/16S rRNA genes: they are (1) easy to align, (2) relatively long (ca. 3.4 kb), and (3) contain more phylogenetically informative variation at 1st and 2nd codon positions. Moreover, the ND4/ND5 gene region is easy to amplify and sequence when employing the protocol suggested herein.     

Alcohol dehydrogenase variability in Hypentelium nigricans

The alcohol dehydrogenase enzyme system of Hypentelium nigricans has been analyzed by means of starch gel electrophoresis yielding two electrophoretically distinct alleles. Clinal variability is suggested with apparent fixation of alleles at the extremes of the sampled range.     

Biochemical systematics of the cyprinid genus Notropis—I. The subgenus Luxilus

Population samples for all taxa in the subgenus Luxilus of Notropis were genetically analysed by vertical starch gel electrophoresis to detect protein variability. A total of 38 alleles were resolved at 17 presumptive loci. Protein systems examined included adenylate kinase, aspartate aminotransferase, creatine kinase, calcium-binding proteins, general protein, glucosephosphate isomerase, glycerol-3-phosphate dehydrogenase, lactate dehydrogenase, malate dehydrogenase, phosphoglucomutase, and superoxide dismutase. A phylogenetic analysis of the molecular data allows the recognition of four species-groups: (a) the cornutus group including Notropis albeolus, N. chrysocephalus chrysocephalus, N. c. isolepis, and N. cornutus: (b) the zonatus group including N. pilsbryi and N. zonatus; (c) the coccogenis group including N. coccogenis and N. zonistius; and (d) the cerasinus group comprised of N. cerasinus alone. Notropis cerasinus exhibits little genetic affinity for the cornutus species-group and is most closely related to the coccogenis species-group. Both phenetic and phylogenetic analyses deny specific status to the isolepis form. A further analysis of isozyme variability at the Pgm-A and Gpi-A loci may clarify the relationship between N. cornutus and N. chrysocephalus.     

Interrelationships of the ostariophysan fishes (Teleostei)

The history of ostariophysan classification is summarized and it is noted that traditional concepts of relationships have never been supported by characters found to be unique to the taxa. We present a new hypothesis of relationships among four of the five major ostariophysan lineages: Cypriniformes, Characiformes, Siluroidei, and Gymnotoidei (Otophysi). Cypriniforms are the sister-group of the remaining three (Characiphysi), and characiforms are the sister-group of siluroids plus gymnotoids (Siluriformes). Placement of the Gonorynchiformes as the sister-group of the Otophysi is supported by additional evidence. Each of the five lineages is monophyletic. Analysis was concentrated upon species thought to be the least specialized within each lineage; choices of these species are discussed. Chanos is determined to be a relatively primitive gonorynchiform morphologically and the sister-group of all other Recent members of the order. Opsariichthys and Zacco are found to be morphologically primitive cypriniforms. We propose that a monophyletic group comprising the Citharinidae and Distichodontidae forms the sister-group of all other characiforms. Within the two families, Xenocharax is the least specialized. We suggest that Hepsetus, the erythrinids, and the ctenoluciids are more derived than the distichodontids and citharinids, and may form a monophyletic group within die characiforms. The traditional hypothesis that Diplomystes is the primitive sister-group of all Recent siluroids is substantiated. Our evidence suggests that Sternopygus is the most primitive gymnotoid morphologically; but rather than being the sister-group of all other gymnotoids, it is the primitive sister-group within a lineage called the Sternopygidae by Mago-Leccia. Previous explanations of otophysan distribution have been based on notions of relationships which are unsupported by the evidence presented herein. Our own analysis of relationships serves primarily to make clear the extent of sympatry, and therefore the probability of dispersal, among the major ostariophysan lineages. The extent of sympatry, together with the widespread distribution of ostariophysans, suggests that the group is older than previously supposed, and our hypotheses of relationships among the characiforms implies that many of the extent characiform lineages evolved before the separation of Africa and South America. Further understanding of ostariophysan distribution must await phylogenetic analysis within each of the five major lineages so that distributions linked with vicariance patterns and dispersal events can be sorted out.     

Biochemical identification of Moxostoma rhothoecum and M. hamiltoni

The acid phosphatase, glycerol-3-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and glucosephosphate isomerase enzyme systems of Moxostoma rhothoecum and M. hamiltoni have been analyzed by means of starch gel electrophoresis. The Roanoke River population has been biochemically identified as M. rhothoecum. Glycerol-3-phosphate dehydrogenase and glucosephosphate isomerase polymorphisms are described in M. rhothoecum.