Fig. 4. Cnesterodon raddai. UMMZ 207503, small stream at bridge on dirt road to Ayolas, Misiones,... more Fig. 4. Cnesterodon raddai. UMMZ 207503, small stream at bridge on dirt road to Ayolas, Misiones, Paraguay: (a) male, 16.9 mm SL; (b) female, 23.2 mm SL.
Fig. 2. Intrageneric relationships of Phalloptychus. The numbers on the branches refer to the cha... more Fig. 2. Intrageneric relationships of Phalloptychus. The numbers on the branches refer to the character state transformations series listed by Lucinda & Reis (2005).
Fig. 6. Tukey box plot of number of bars along flanks in female specimens of Phalloptychus januar... more Fig. 6. Tukey box plot of number of bars along flanks in female specimens of Phalloptychus januarius and P. iheringii. Significant differences were found between P. januarius (Rio de Janeiro, São Paulo and Paraná) and P. iheringii populations (Santa Catarina and Rio Grande do Sul). * Type locality of P. januarius, ** type locality of P. iheringii.
FIGURE 3. Distribution of Moenkhausia hysterosticta. Some symbols represent more than one lot or ... more FIGURE 3. Distribution of Moenkhausia hysterosticta. Some symbols represent more than one lot or locality. T = Typelocality.
The geometry of the dangling base in 105 published structures (from X-ray/NMR) containing single-... more The geometry of the dangling base in 105 published structures (from X-ray/NMR) containing single-stranded overhangs has been analyzed and correlated to the thermodynamic stabilization found (UV) for the corresponding dangling base/closing basepair combination in short oligonucleotides. The study considers most combinations of closing basepairs, sequence and dangling base residue type, attached in both the 3′-and 5′-ends of both DNA and RNA. Linear regression analysis showed a straightforward correlation (R ) 0.873) between the degree of screening for the hydrogen bonds of the closing basepair provided by the dangling base and the resulting thermodynamic stabilization in both DNA and RNA series with dangling ends either at the 3′-or at the 5′-terminus. Regression analysis of only the datasets from RNA gives an improved correlation, R ) 0.934, showing that dangling ends on RNA are more ordered than the dangling ends on DNA, R ) 0.376. This study highlights the gain in the free energy of stabilization owing to the favorable stacking between the dangling nucleobase and the neighboring basepair and the resulting strengthening of the hydrogen bond of the closing basepair. By acting as a hydrophobic cap on the terminal of the DNA or RNA duplex, the dangling-end residue restricts the bulk water access to the terminal basepair, thereby providing it with a microenvironment devoid of water, which consequently enhances its thermodynamic stability, making it energetically comparable to the corresponding internal basepair. Thus, one single structural model consisting of the interplay of the above electrostatic interactions can be used to explain the molecular basis of the observed thermodynamic effects for dangling-end attachment to the 3′-and 5′-ends of both DNA and RNA duplexes, which is a key step toward accurate dangling-end effect prediction.
FIGURE 1. Geophagus sveni, new species. Holotype, MCP 43666, 130.3 mm SL; Rio Tocantins, Lajeado ... more FIGURE 1. Geophagus sveni, new species. Holotype, MCP 43666, 130.3 mm SL; Rio Tocantins, Lajeado Hydroelectric Reservoir, Porto Nacional, Tocantins, Brazil.
A new species of the genus Bryconops , subgenus Bryconops , is described from the rio Conceição, ... more A new species of the genus Bryconops , subgenus Bryconops , is described from the rio Conceição, a tributary to the rio Palma, upper rio Tocantins drainage, Tocantins State, Brazil. The new species is distinguished from all its congeners, except B. humeralis and B. vibex by the color pattern in vivo (dorsal, adipose, and caudal fins entirely orange). The new species is easily distinguished from B. humeralis and B. vibex by the absence of a humeral spot and by the lack of maxillary teeth (vs . presence of a single humeral spot and presence of 1-3 maxillary teeth on both sides). Furthermore, the new species is distinguished from B. vibex by the number of perforated lateral line scales (38-41 vs. 44-46).
A new characid species, Jupiaba elassonaktis, is described from the rio Tocantins drainage. The n... more A new characid species, Jupiaba elassonaktis, is described from the rio Tocantins drainage. The new species is distinguished from its congeners by the following combination of characters: medial cusps of premaxillary teeth much larger than remaining cusps, dentary teeth decreasing abruptly in size from the fifth tooth backwards, first dorsal-and anal-fin rays not prolonged by an elongate filament, presence of a vertically elongate humeral spot, 33-39 scales on lateral line, 5-7 scales series above lateral line, 9-11 pectoral-fin rays, and a incomplete series of median predorsal scales.
A recent study based on genomic data by Roxo et al. (2019) provided a phylogeny of the Loricariid... more A recent study based on genomic data by Roxo et al. (2019) provided a phylogeny of the Loricariidae, the largest catfish family and second largest Neotropical fish family with approximately 1,000 species. The study represents a valuable and innovative contribution for understanding higher-level relationships within the family. The phylogenetic tree inferred by Roxo et al. (2019) thoroughly corroborates the monophyly and relationships of most currently accepted subfamilies of Loricariidae, based on a fair taxon sampling (nearly 14% of the species in the family) representing most genera of each but one of the subfamilies, the Lithogeninae, the sister-group of the remaining members of the family (Pereira & Reis, 2017; Reis et al., 2017). In addition to a hypothesis of relationships, Roxo et al. (2019) also proposed a series of lower-level taxonomic changes, which are deemed premature considering that the taxonomic sampling of the study targeted higher-level clades, and go against one o...
The Lajeado HR is the fourth hydroelectric power plant constructed in the rio Tocantins. The impl... more The Lajeado HR is the fourth hydroelectric power plant constructed in the rio Tocantins. The implementation of hydroelectric plants in the rio Tocantins basin is of high environmental concern because they may result in severe damage to the ichthyofauna. A species list of the area of influence of the Lajeado HR is provided, in the hope that it will contribute to the knowledge of this potentially threatened ichthyofauna. A few comments on the ichthyofauna of the rio Tocantins drainage are also provided.
Fig. 4. Cnesterodon raddai. UMMZ 207503, small stream at bridge on dirt road to Ayolas, Misiones,... more Fig. 4. Cnesterodon raddai. UMMZ 207503, small stream at bridge on dirt road to Ayolas, Misiones, Paraguay: (a) male, 16.9 mm SL; (b) female, 23.2 mm SL.
Fig. 2. Intrageneric relationships of Phalloptychus. The numbers on the branches refer to the cha... more Fig. 2. Intrageneric relationships of Phalloptychus. The numbers on the branches refer to the character state transformations series listed by Lucinda & Reis (2005).
Fig. 6. Tukey box plot of number of bars along flanks in female specimens of Phalloptychus januar... more Fig. 6. Tukey box plot of number of bars along flanks in female specimens of Phalloptychus januarius and P. iheringii. Significant differences were found between P. januarius (Rio de Janeiro, São Paulo and Paraná) and P. iheringii populations (Santa Catarina and Rio Grande do Sul). * Type locality of P. januarius, ** type locality of P. iheringii.
FIGURE 3. Distribution of Moenkhausia hysterosticta. Some symbols represent more than one lot or ... more FIGURE 3. Distribution of Moenkhausia hysterosticta. Some symbols represent more than one lot or locality. T = Typelocality.
The geometry of the dangling base in 105 published structures (from X-ray/NMR) containing single-... more The geometry of the dangling base in 105 published structures (from X-ray/NMR) containing single-stranded overhangs has been analyzed and correlated to the thermodynamic stabilization found (UV) for the corresponding dangling base/closing basepair combination in short oligonucleotides. The study considers most combinations of closing basepairs, sequence and dangling base residue type, attached in both the 3′-and 5′-ends of both DNA and RNA. Linear regression analysis showed a straightforward correlation (R ) 0.873) between the degree of screening for the hydrogen bonds of the closing basepair provided by the dangling base and the resulting thermodynamic stabilization in both DNA and RNA series with dangling ends either at the 3′-or at the 5′-terminus. Regression analysis of only the datasets from RNA gives an improved correlation, R ) 0.934, showing that dangling ends on RNA are more ordered than the dangling ends on DNA, R ) 0.376. This study highlights the gain in the free energy of stabilization owing to the favorable stacking between the dangling nucleobase and the neighboring basepair and the resulting strengthening of the hydrogen bond of the closing basepair. By acting as a hydrophobic cap on the terminal of the DNA or RNA duplex, the dangling-end residue restricts the bulk water access to the terminal basepair, thereby providing it with a microenvironment devoid of water, which consequently enhances its thermodynamic stability, making it energetically comparable to the corresponding internal basepair. Thus, one single structural model consisting of the interplay of the above electrostatic interactions can be used to explain the molecular basis of the observed thermodynamic effects for dangling-end attachment to the 3′-and 5′-ends of both DNA and RNA duplexes, which is a key step toward accurate dangling-end effect prediction.
FIGURE 1. Geophagus sveni, new species. Holotype, MCP 43666, 130.3 mm SL; Rio Tocantins, Lajeado ... more FIGURE 1. Geophagus sveni, new species. Holotype, MCP 43666, 130.3 mm SL; Rio Tocantins, Lajeado Hydroelectric Reservoir, Porto Nacional, Tocantins, Brazil.
A new species of the genus Bryconops , subgenus Bryconops , is described from the rio Conceição, ... more A new species of the genus Bryconops , subgenus Bryconops , is described from the rio Conceição, a tributary to the rio Palma, upper rio Tocantins drainage, Tocantins State, Brazil. The new species is distinguished from all its congeners, except B. humeralis and B. vibex by the color pattern in vivo (dorsal, adipose, and caudal fins entirely orange). The new species is easily distinguished from B. humeralis and B. vibex by the absence of a humeral spot and by the lack of maxillary teeth (vs . presence of a single humeral spot and presence of 1-3 maxillary teeth on both sides). Furthermore, the new species is distinguished from B. vibex by the number of perforated lateral line scales (38-41 vs. 44-46).
A new characid species, Jupiaba elassonaktis, is described from the rio Tocantins drainage. The n... more A new characid species, Jupiaba elassonaktis, is described from the rio Tocantins drainage. The new species is distinguished from its congeners by the following combination of characters: medial cusps of premaxillary teeth much larger than remaining cusps, dentary teeth decreasing abruptly in size from the fifth tooth backwards, first dorsal-and anal-fin rays not prolonged by an elongate filament, presence of a vertically elongate humeral spot, 33-39 scales on lateral line, 5-7 scales series above lateral line, 9-11 pectoral-fin rays, and a incomplete series of median predorsal scales.
A recent study based on genomic data by Roxo et al. (2019) provided a phylogeny of the Loricariid... more A recent study based on genomic data by Roxo et al. (2019) provided a phylogeny of the Loricariidae, the largest catfish family and second largest Neotropical fish family with approximately 1,000 species. The study represents a valuable and innovative contribution for understanding higher-level relationships within the family. The phylogenetic tree inferred by Roxo et al. (2019) thoroughly corroborates the monophyly and relationships of most currently accepted subfamilies of Loricariidae, based on a fair taxon sampling (nearly 14% of the species in the family) representing most genera of each but one of the subfamilies, the Lithogeninae, the sister-group of the remaining members of the family (Pereira & Reis, 2017; Reis et al., 2017). In addition to a hypothesis of relationships, Roxo et al. (2019) also proposed a series of lower-level taxonomic changes, which are deemed premature considering that the taxonomic sampling of the study targeted higher-level clades, and go against one o...
The Lajeado HR is the fourth hydroelectric power plant constructed in the rio Tocantins. The impl... more The Lajeado HR is the fourth hydroelectric power plant constructed in the rio Tocantins. The implementation of hydroelectric plants in the rio Tocantins basin is of high environmental concern because they may result in severe damage to the ichthyofauna. A species list of the area of influence of the Lajeado HR is provided, in the hope that it will contribute to the knowledge of this potentially threatened ichthyofauna. A few comments on the ichthyofauna of the rio Tocantins drainage are also provided.
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