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Cleusa Yoshiko Nagamachi - One of the best experts on this subject based on the ideXlab platform.
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Karyotypic Diversity and Evolution in a Sympatric Assemblage of Neotropical Electric Knifefish.
Frontiers in genetics, 2018Co-Authors: Adauto Lima Cardoso, Julio Cesar Pieczarka, William G. R. Crampton, Joseph C. Waddell, Jonathan Stuart Ready, Wilsea M. B. De Figueiredo Ready, Jonas Alves De Oliveira, Cleusa Yoshiko NagamachiAbstract:Chromosome changes can perform an important role in speciation by acting as post-zygotic reproductive barriers. The Neotropical electric fish genus Brachyhypopomus (Gymnotiformes, Hypopomidae) has 28 described species, but cytogenetic data are hitherto available only for four of them. To understand karyotype evolution and investigate the possible role of chromosome changes in the diversification of this genus, we describe here the karyotype of eight species of Brachyhypopomus from a sympatric assemblage in the central Amazon basin. We analysed cytogenetic data in the context of a phylogenetic reconstruction of the genus and known patterns of geographical distribution. We found a strong phylogenetic signal for chromosome number, and noted that sympatric species have exclusive karyotypes. Additional insights into the role of chromosome changes in the diversification of Brachyhypopomus are discussed.
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The Karyotype of Microsternarchus aff. bilineatus: A First Case of Y Chromosome Degeneration in Gymnotiformes
Zebrafish, 2017Co-Authors: Jéssica Almeida Batista, Julio Cesar Pieczarka, Adauto Lima Cardoso, Susana Suely Rodrigues Milhomem-paixão, Jonathan Stuart Ready, Cleusa Yoshiko NagamachiAbstract:Various species and lineages that until recently were identified as Microsternarchus bilineatus (Hypopomidae, Gymnotiformes) have a widespread distribution in the Amazon and Orinoco River basins and across the Guiana shield. Recent molecular studies show five distinct lineages for Microsternarchus from different localities. These results suggest that this previously monotypic genus actually consists of more than one species. Here, we describe the karyotype of M. aff. bilineatus from the Cururutuia River (Braganca, Para, Brazil). The diploid number of 48 chromosomes (14 meta-submetacentric/34 subtelo-acrocentric) is found for males and females, with an XX/XY sex chromosome system. The nucleolar organizer region is found in the short arm of pair 9. Constitutive heterochromatin occurs in the pericentromeric region of all chromosomes, in the distal region of 3p, 5p, 7p, 8q, 9q, 16q, and Xq, in the interstitial region in 2p, 10q, 11q, and 12q and all along 4p, and in a large block of the Y chromosome. These results indicate extensive karyotype divergence between this population and samples from Igarape Taruma Grande (Negro River, Amazonas, Brazil) studied by other researchers. Moreover, despite the diversity of sex chromosome systems found in Gymnotiformes, the XX/XY sex chromosome system of M. aff. bilineatus is the first case of Y chromosome degeneration in this order. The present data are valuable to help understand karyotype evolution in Hypopomidae.
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X1X1X2X2/X1X2Y sex chromosome systems in the Neotropical Gymnotiformes electric fish of the genus Brachyhypopomus.
Genetics and molecular biology, 2015Co-Authors: Adauto Lima Cardoso, Julio Cesar Pieczarka, Cleusa Yoshiko NagamachiAbstract:Several types of sex chromosome systems have been recorded among Gymnotiformes, including male and female heterogamety, simple and multiple sex chromosomes, and different mechanisms of origin and evolution. The X1X1X2X2/X1X2Y systems identified in three species of this order are considered homoplasic for the group. In the genus Brachyhypopomus, only B. gauderio presented this type of system. Herein we describe the karyotypes of Brachyhypopomus pinnicaudatus and B. n. sp. FLAV, which have an X1X1X2X2/X1X2Y sex chromosome system that evolved via fusion between an autosome and the Y chromosome. The morphology of the chromosomes and the meiotic pairing suggest that the sex chromosomes of B. gauderio and B. pinnicaudatus have a common origin, whereas in B . n. sp. FLAV the sex chromosome system evolved independently. However, we cannot discard the possibility of common origin followed by distinct processes of differentiation. The identification of two new karyotypes with an X1X1X2X2/X1X2Y sex chromosome system in Gymnotiformes makes it the most common among the karyotyped species of the group. Comparisons of these karyotypes and the evolutionary history of the taxa indicate independent origins for their sex chromosomes systems. The recurrent emergence of the X1X1X2X2/X1X2Y system may represent sex chromosomes turnover events in Gymnotiformes.
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x1x1x2x2 x1x2y sex chromosome systems in the neotropical Gymnotiformes electric fish of the genus brachyhypopomus
Genetics and Molecular Biology, 2015Co-Authors: Adauto Lima Cardoso, Julio Cesar Pieczarka, Cleusa Yoshiko NagamachiAbstract:Several types of sex chromosome systems have been recorded among Gymnotiformes, including male and female heterogamety, simple and multiple sex chromosomes, and different mechanisms of origin and evolution. The X1X1X2X2/X1X2Y systems identified in three species of this order are considered homoplasic for the group. In the genus Brachyhypopomus, only B. gauderio presented this type of system. Herein we describe the karyotypes of Brachyhypopomus pinnicaudatus and B. n. sp. FLAV, which have an X1X1X2X2/X1X2Y sex chromosome system that evolved via fusion between an autosome and the Y chromosome. The morphology of the chromosomes and the meiotic pairing suggest that the sex chromosomes of B. gauderio and B. pinnicaudatus have a common origin, whereas in B . n. sp. FLAV the sex chromosome system evolved independently. However, we cannot discard the possibility of common origin followed by distinct processes of differentiation. The identification of two new karyotypes with an X1X1X2X2/X1X2Y sex chromosome system in Gymnotiformes makes it the most common among the karyotyped species of the group. Comparisons of these karyotypes and the evolutionary history of the taxa indicate independent origins for their sex chromosomes systems. The recurrent emergence of the X1X1X2X2/X1X2Y system may represent sex chromosomes turnover events in Gymnotiformes.
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Are NORs always located on homeologous chromosomes? A FISH investigation with rDNA and whole chromosome probes in Gymnotus fishes (Gymnotiformes).
PloS one, 2013Co-Authors: Susana Suely Rodrigues Milhomem, Julio Cesar Pieczarka, Fausto Foresti, Priscilla Cardim Scacchetti, Patricia C. M. O’brien, Malcolm A. Ferguson-smith, Jose ́ C. Pansonato-alves, Cleusa Yoshiko NagamachiAbstract:Gymnotus (Gymnotiformes, Gymnotidae) is the most diverse known Neotropical electric knife fish genus. Cytogenetic studies in Gymnotus demonstrate a huge karyotypic diversity for this genus, with diploid numbers ranging from 34 to 54. The NOR are also variable in this genus, with both single and multiple NORs described. A common interpretation is that the single NOR pair is a primitive trait while multiple NORs are derivative. However this hypothesis has never been fully tested. In this report we checked if the NOR-bearing chromosome and the rDNA site are homeologous in different species of the genus Gymnotus: G. carapo (2n = 40, 42, 54), G. mamiraua (2n = 54), G. arapaima (2n = 44), G. sylvius (2n = 40), G. inaequilabiatus (2n = 54) and G. capanema (2n = 34), from the monophyletic group G. carapo (Gymnotidae-Gymnotiformes), as well as G. jonasi (2n = 52), belonging to the G1 group. They were analyzed with Fluorescence in situ hybridization (FISH) using 18S rDNA and whole chromosome probes of the NOR-bearing chromosome 20 (GCA20) of G. carapo (cytotype 2n = 42), obtained by Fluorescence Activated Cell Sorting. All species of the monophyletic G. carapo group show the NOR in the same single pair, confirmed by hybridization with CGA20 whole chromosome probe. In G. jonasi the NORs are multiple, and located on pairs 9, 10 and 11. In G. jonasi the GCA20 chromosome probe paints the distal half of the long arm of pair 7, which is not a NOR-bearing chromosome. Thus these rDNA sequences are not always in the homeologous chromosomes in different species thus giving no support to the hypothesis that single NOR pairs are primitive traits while multiple NORs are derived. The separation of groups of species in the genus Gymnotus proposed by phylogenies with morphologic and molecular data is supported by our cytogenetic data.
Julio Cesar Pieczarka - One of the best experts on this subject based on the ideXlab platform.
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Karyotypic Diversity and Evolution in a Sympatric Assemblage of Neotropical Electric Knifefish.
Frontiers in genetics, 2018Co-Authors: Adauto Lima Cardoso, Julio Cesar Pieczarka, William G. R. Crampton, Joseph C. Waddell, Jonathan Stuart Ready, Wilsea M. B. De Figueiredo Ready, Jonas Alves De Oliveira, Cleusa Yoshiko NagamachiAbstract:Chromosome changes can perform an important role in speciation by acting as post-zygotic reproductive barriers. The Neotropical electric fish genus Brachyhypopomus (Gymnotiformes, Hypopomidae) has 28 described species, but cytogenetic data are hitherto available only for four of them. To understand karyotype evolution and investigate the possible role of chromosome changes in the diversification of this genus, we describe here the karyotype of eight species of Brachyhypopomus from a sympatric assemblage in the central Amazon basin. We analysed cytogenetic data in the context of a phylogenetic reconstruction of the genus and known patterns of geographical distribution. We found a strong phylogenetic signal for chromosome number, and noted that sympatric species have exclusive karyotypes. Additional insights into the role of chromosome changes in the diversification of Brachyhypopomus are discussed.
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Table_2.docx
2018Co-Authors: Adauto L. Cardoso, Julio Cesar Pieczarka, William G. R. Crampton, Joseph C. Waddell, Wilsea M. B. De Figueiredo Ready, Jonas Alves De Oliveira, Jonathan S. Ready, Cleusa Y. NagamachiAbstract:Chromosome changes can perform an important role in speciation by acting as post-zygotic reproductive barriers. The Neotropical electric fish genus Brachyhypopomus (Gymnotiformes, Hypopomidae) has 28 described species, but cytogenetic data are hitherto available only for four of them. To understand karyotype evolution and investigate the possible role of chromosome changes in the diversification of this genus, we describe here the karyotype of eight species of Brachyhypopomus from a sympatric assemblage in the central Amazon basin. We analyzed cytogenetic data in the context of a phylogenetic reconstruction of the genus and known patterns of geographical distribution. We found a strong phylogenetic signal for chromosome number and noted that sympatric species have exclusive karyotypes. Additional insights into the role of chromosome changes in the diversification of Brachyhypopomus are discussed.
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The Karyotype of Microsternarchus aff. bilineatus: A First Case of Y Chromosome Degeneration in Gymnotiformes
Zebrafish, 2017Co-Authors: Jéssica Almeida Batista, Julio Cesar Pieczarka, Adauto Lima Cardoso, Susana Suely Rodrigues Milhomem-paixão, Jonathan Stuart Ready, Cleusa Yoshiko NagamachiAbstract:Various species and lineages that until recently were identified as Microsternarchus bilineatus (Hypopomidae, Gymnotiformes) have a widespread distribution in the Amazon and Orinoco River basins and across the Guiana shield. Recent molecular studies show five distinct lineages for Microsternarchus from different localities. These results suggest that this previously monotypic genus actually consists of more than one species. Here, we describe the karyotype of M. aff. bilineatus from the Cururutuia River (Braganca, Para, Brazil). The diploid number of 48 chromosomes (14 meta-submetacentric/34 subtelo-acrocentric) is found for males and females, with an XX/XY sex chromosome system. The nucleolar organizer region is found in the short arm of pair 9. Constitutive heterochromatin occurs in the pericentromeric region of all chromosomes, in the distal region of 3p, 5p, 7p, 8q, 9q, 16q, and Xq, in the interstitial region in 2p, 10q, 11q, and 12q and all along 4p, and in a large block of the Y chromosome. These results indicate extensive karyotype divergence between this population and samples from Igarape Taruma Grande (Negro River, Amazonas, Brazil) studied by other researchers. Moreover, despite the diversity of sex chromosome systems found in Gymnotiformes, the XX/XY sex chromosome system of M. aff. bilineatus is the first case of Y chromosome degeneration in this order. The present data are valuable to help understand karyotype evolution in Hypopomidae.
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Are NORs Always Located on Homeologous Chromosomes? A FISH Investigation with rDNA and Whole Chromosome Probes in Gymnotus Fishes (Gymnotiformes)
2016Co-Authors: Susana Suely Rodrigues Milhomem, Julio Cesar Pieczarka, Fausto Foresti, Patricia C. M. O’brien, Malcolm A. Ferguson-smith, Priscilla C. Scacchetti, Jose ́ C. Pansonato-alves, Cleusa Y. NagamachiAbstract:Gymnotus (Gymnotiformes, Gymnotidae) is the most diverse known Neotropical electric knife fish genus. Cytogenetic studies in Gymnotus demonstrate a huge karyotypic diversity for this genus, with diploid numbers ranging from 34 to 54. The NOR are also variable in this genus, with both single and multiple NORs described. A common interpretation is that the single NOR pair is a primitive trait while multiple NORs are derivative. However this hypothesis has never been fully tested. In this report we checked if the NOR-bearing chromosome and the rDNA site are homeologous in different species of the genus Gymnotus: G. carapo (2n = 40, 42, 54), G. mamiraua (2n = 54), G. arapaima (2n = 44), G. sylvius (2n = 40), G. inaequilabiatus (2n = 54) and G. capanema (2n = 34), from the monophyletic group G. carapo (Gymnotidae-Gymnotiformes), as well as G. jonasi (2n = 52), belonging to the G1 group. They were analyzed with Fluorescence in situ hybridization (FISH) using 18S rDNA and whole chromosome probes of the NOR-bearing chromosome 20 (GCA20) of G. carapo (cytotype 2n = 42), obtained by Fluorescence Activated Cell Sorting. All species of the monophyletic G. carapo group show the NOR in the same single pair, confirmed by hybridization with CGA20 whole chromosome probe. In G. jonasi the NORs are multiple, and located on pairs 9, 10 and 11. In G. jonasi the GCA20 chromosome probe paints the distal half of the long arm of pair 7, which is not a NOR-bearing chromosome. Thus these rDNA sequences are not always in the homeologous chromosomes in different species thus giving no support to the hypothesis that single NOR pairs are primitive traits while multiple NORs ar
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X1X1X2X2/X1X2Y sex chromosome systems in the Neotropical Gymnotiformes electric fish of the genus Brachyhypopomus.
Genetics and molecular biology, 2015Co-Authors: Adauto Lima Cardoso, Julio Cesar Pieczarka, Cleusa Yoshiko NagamachiAbstract:Several types of sex chromosome systems have been recorded among Gymnotiformes, including male and female heterogamety, simple and multiple sex chromosomes, and different mechanisms of origin and evolution. The X1X1X2X2/X1X2Y systems identified in three species of this order are considered homoplasic for the group. In the genus Brachyhypopomus, only B. gauderio presented this type of system. Herein we describe the karyotypes of Brachyhypopomus pinnicaudatus and B. n. sp. FLAV, which have an X1X1X2X2/X1X2Y sex chromosome system that evolved via fusion between an autosome and the Y chromosome. The morphology of the chromosomes and the meiotic pairing suggest that the sex chromosomes of B. gauderio and B. pinnicaudatus have a common origin, whereas in B . n. sp. FLAV the sex chromosome system evolved independently. However, we cannot discard the possibility of common origin followed by distinct processes of differentiation. The identification of two new karyotypes with an X1X1X2X2/X1X2Y sex chromosome system in Gymnotiformes makes it the most common among the karyotyped species of the group. Comparisons of these karyotypes and the evolutionary history of the taxa indicate independent origins for their sex chromosomes systems. The recurrent emergence of the X1X1X2X2/X1X2Y system may represent sex chromosomes turnover events in Gymnotiformes.
Adauto Lima Cardoso - One of the best experts on this subject based on the ideXlab platform.
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Karyotypic Diversity and Evolution in a Sympatric Assemblage of Neotropical Electric Knifefish.
Frontiers in genetics, 2018Co-Authors: Adauto Lima Cardoso, Julio Cesar Pieczarka, William G. R. Crampton, Joseph C. Waddell, Jonathan Stuart Ready, Wilsea M. B. De Figueiredo Ready, Jonas Alves De Oliveira, Cleusa Yoshiko NagamachiAbstract:Chromosome changes can perform an important role in speciation by acting as post-zygotic reproductive barriers. The Neotropical electric fish genus Brachyhypopomus (Gymnotiformes, Hypopomidae) has 28 described species, but cytogenetic data are hitherto available only for four of them. To understand karyotype evolution and investigate the possible role of chromosome changes in the diversification of this genus, we describe here the karyotype of eight species of Brachyhypopomus from a sympatric assemblage in the central Amazon basin. We analysed cytogenetic data in the context of a phylogenetic reconstruction of the genus and known patterns of geographical distribution. We found a strong phylogenetic signal for chromosome number, and noted that sympatric species have exclusive karyotypes. Additional insights into the role of chromosome changes in the diversification of Brachyhypopomus are discussed.
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The Karyotype of Microsternarchus aff. bilineatus: A First Case of Y Chromosome Degeneration in Gymnotiformes
Zebrafish, 2017Co-Authors: Jéssica Almeida Batista, Julio Cesar Pieczarka, Adauto Lima Cardoso, Susana Suely Rodrigues Milhomem-paixão, Jonathan Stuart Ready, Cleusa Yoshiko NagamachiAbstract:Various species and lineages that until recently were identified as Microsternarchus bilineatus (Hypopomidae, Gymnotiformes) have a widespread distribution in the Amazon and Orinoco River basins and across the Guiana shield. Recent molecular studies show five distinct lineages for Microsternarchus from different localities. These results suggest that this previously monotypic genus actually consists of more than one species. Here, we describe the karyotype of M. aff. bilineatus from the Cururutuia River (Braganca, Para, Brazil). The diploid number of 48 chromosomes (14 meta-submetacentric/34 subtelo-acrocentric) is found for males and females, with an XX/XY sex chromosome system. The nucleolar organizer region is found in the short arm of pair 9. Constitutive heterochromatin occurs in the pericentromeric region of all chromosomes, in the distal region of 3p, 5p, 7p, 8q, 9q, 16q, and Xq, in the interstitial region in 2p, 10q, 11q, and 12q and all along 4p, and in a large block of the Y chromosome. These results indicate extensive karyotype divergence between this population and samples from Igarape Taruma Grande (Negro River, Amazonas, Brazil) studied by other researchers. Moreover, despite the diversity of sex chromosome systems found in Gymnotiformes, the XX/XY sex chromosome system of M. aff. bilineatus is the first case of Y chromosome degeneration in this order. The present data are valuable to help understand karyotype evolution in Hypopomidae.
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X1X1X2X2/X1X2Y sex chromosome systems in the Neotropical Gymnotiformes electric fish of the genus Brachyhypopomus.
Genetics and molecular biology, 2015Co-Authors: Adauto Lima Cardoso, Julio Cesar Pieczarka, Cleusa Yoshiko NagamachiAbstract:Several types of sex chromosome systems have been recorded among Gymnotiformes, including male and female heterogamety, simple and multiple sex chromosomes, and different mechanisms of origin and evolution. The X1X1X2X2/X1X2Y systems identified in three species of this order are considered homoplasic for the group. In the genus Brachyhypopomus, only B. gauderio presented this type of system. Herein we describe the karyotypes of Brachyhypopomus pinnicaudatus and B. n. sp. FLAV, which have an X1X1X2X2/X1X2Y sex chromosome system that evolved via fusion between an autosome and the Y chromosome. The morphology of the chromosomes and the meiotic pairing suggest that the sex chromosomes of B. gauderio and B. pinnicaudatus have a common origin, whereas in B . n. sp. FLAV the sex chromosome system evolved independently. However, we cannot discard the possibility of common origin followed by distinct processes of differentiation. The identification of two new karyotypes with an X1X1X2X2/X1X2Y sex chromosome system in Gymnotiformes makes it the most common among the karyotyped species of the group. Comparisons of these karyotypes and the evolutionary history of the taxa indicate independent origins for their sex chromosomes systems. The recurrent emergence of the X1X1X2X2/X1X2Y system may represent sex chromosomes turnover events in Gymnotiformes.
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x1x1x2x2 x1x2y sex chromosome systems in the neotropical Gymnotiformes electric fish of the genus brachyhypopomus
Genetics and Molecular Biology, 2015Co-Authors: Adauto Lima Cardoso, Julio Cesar Pieczarka, Cleusa Yoshiko NagamachiAbstract:Several types of sex chromosome systems have been recorded among Gymnotiformes, including male and female heterogamety, simple and multiple sex chromosomes, and different mechanisms of origin and evolution. The X1X1X2X2/X1X2Y systems identified in three species of this order are considered homoplasic for the group. In the genus Brachyhypopomus, only B. gauderio presented this type of system. Herein we describe the karyotypes of Brachyhypopomus pinnicaudatus and B. n. sp. FLAV, which have an X1X1X2X2/X1X2Y sex chromosome system that evolved via fusion between an autosome and the Y chromosome. The morphology of the chromosomes and the meiotic pairing suggest that the sex chromosomes of B. gauderio and B. pinnicaudatus have a common origin, whereas in B . n. sp. FLAV the sex chromosome system evolved independently. However, we cannot discard the possibility of common origin followed by distinct processes of differentiation. The identification of two new karyotypes with an X1X1X2X2/X1X2Y sex chromosome system in Gymnotiformes makes it the most common among the karyotyped species of the group. Comparisons of these karyotypes and the evolutionary history of the taxa indicate independent origins for their sex chromosomes systems. The recurrent emergence of the X1X1X2X2/X1X2Y system may represent sex chromosomes turnover events in Gymnotiformes.
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Chromosomal characterization of two species of genus Steatogenys (Gymnotiformes: Rhamphichthyoidea: Steatogenini) from the Amazon basin: sex chromosomes and correlations with Gymnotiformes phylogeny
Reviews in Fish Biology and Fisheries, 2011Co-Authors: Adauto Lima Cardoso, Eliana Feldberg, Danillo Dos Santos Silva, Julio Cesar Pieczarka, Susana Suely Rodrigues Milhomem, Thiago Moreira-almeida, Patrícia Corrêa Da Silva, Cleusa Yoshiko NagamachiAbstract:Gymnotiformes are an important component of the Neotropical ichthyofauna and they are known for their ability to generate and detect electrical discharges. Phylogenetic relationships of Gymnotiformes are still not well understood. However, the monophyly of the superfamily Rhamphichthyoidea is well accepted, despite the position of tribe Steatogenini (Steatogenys, Hypopygus and Stegostenopos) within this superfamily is unclear. The genus Steatogenys includes three species that, together with Hypopygus and Stegostenopos, form tribe Steatogenini. Cytogenetic information is currently only available for Hypopygus lepturus. Here, we describe the karyotypes of Steatogenys elegans from four localities and S. duidae from two localities. S. elegans was found to have 2n = 50, ZZ/ZW (12m-sm/38st-a), while S. duidae had 2n = 50 (50m-sm). In S. elegans, constitutive heterochromatin (CH) was observed in the centromeric regions of all chromosomes, in the interstitial region of 1q, and in two blocks of Wq. In S. duidae, CH was observed in the centromeric and pericentromeric regions of all chromosomes, and in the interstitial regions of 2q, 3q, 5q, and 7q. Nucleolar organizer regions (NORs) were identified in the distal regions of one chromosome pair in each species. The CMA3 fluorochrome (specific to G-C rich regions) coincided with the NORs in both species, and with the HC of S. elegans except on chromosome pair 5 and the W. The DAPI fluorochrome (specific to A-T rich regions) coincided with the CH of both species, and was very intense for chromosome pair 5 and the W of S. elegans. Our observations suggest that the ZZ/ZW system observed in S. elegans likely evolved through CH addition followed by a paracentric inversion. The chromosomal data described herein are consistent with the phylogenetic hypothesis that tribe Steatogenini should be positioned within family Ramphychthyidae.
M Winslow - One of the best experts on this subject based on the ideXlab platform.
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A quantitative analysis of passive electrolocation behavior in electric fish.
Brain Behavior and Evolution, 2008Co-Authors: C D Hopkins, K T Shieh, D W Mcbride, M WinslowAbstract:Weakly electric fish of the families Gymnotidae and Hypopomidae (Gymnotiformes) are able to locate the electric discharges from conspecifics or from dipole electrodes, and they demonstrate this by mak
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A Quantitative Analysis of Passive Electrolocation Behavior in Electric Fish; pp. 45–59
Brain Behavior and Evolution, 1997Co-Authors: C D Hopkins, K T Shieh, D W Mcbride, M WinslowAbstract:Weakly electric fish of the families Gymnotidae and Hypopomidae (Gymnotiformes) are able to locate the electric discharges from conspecifics or from dipole electrodes, and they demonstrate this by mak
James S. Albert - One of the best experts on this subject based on the ideXlab platform.
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Molecular phylogeny of the ghost knifefishes (Gymnotiformes: Apteronotidae).
Molecular phylogenetics and evolution, 2019Co-Authors: Maxwell J. Bernt, Victor A. Tagliacollo, James S. AlbertAbstract:Abstract Ghost knifefishes (Gymnotiformes: Apteronotidae) are weakly electric fishes that possess a high-frequency, neurogenic electric organ discharge. They are found throughout the humid Neotropics from Panama to Argentina and are most diverse and abundant in the channels of large lowland rivers. Apteronotidae is the most species-rich family of Neotropical electric knifefishes with 96 valid species in 15 genera. We present a phylogenetic hypothesis based on molecular sequence data from three mitochondrial genes (16S, coi, cytb) and four nuclear loci (glyt, rag2, ryr3, zic1). Our analysis includes sequence data for 203 samples in 54 species and 14 genera, making it the most densely-sampled and data-rich phylogeny of the Apteronotidae to date. Our results corroborate previous phylogenetic hypotheses with the placement of Orthosternarchus + Sternarchorhamphus sister to all other apteronotids, a non-monophyletic Apterontotus, and a sister relationship between Sternarchorhynchus and the Navajini. We also report several novel relationships, particularly within the Navajini and among several species of the nominal genus Apteronotus not previously included in phylogenetic analyses. We additionally provide a new classification for the family.
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A New Species of Deep-channel Electric Knifefish Compsaraia (Apteronotidae, Gymnotiformes) from the Amazon River
2017Co-Authors: Maxwell J. Bernt, James S. AlbertAbstract:Maxwell J. Bernt, James S. Albert (2017): A New Species of Deep-channel Electric Knifefish Compsaraia (Apteronotidae, Gymnotiformes) from the Amazon River. Copeia 105 (2): 211-219, DOI: 10.1643/CI-16-52
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Fluctuations in Evolutionary Integration Allow for Big Brains and Disparate Faces
Scientific Reports, 2017Co-Authors: Kory M. Evans, Victor A. Tagliacollo, Brandon T. Waltz, Brian L. Sidlauskas, James S. AlbertAbstract:In theory, evolutionary modularity allows anatomical structures to respond differently to selective regimes, thus promoting morphological diversification. These differences can then influence the rate and direction of phenotypic evolution among structures. Here we use geometric morphometrics and phenotypic matrix statistics to compare rates of craniofacial evolution and estimate evolvability in the face and braincase modules of a clade of teleost fishes (Gymnotiformes) and a clade of mammals (Carnivora), both of which exhibit substantial craniofacial diversity. We find that the face and braincase regions of both clades display different degrees of integration. We find that the face and braincase evolve at similar rates in Gymnotiformes and the reverse in Carnivora with the braincase evolving twice as fast as the face. Estimates of evolvability and constraints in these modules suggest differential responses to selection arising from fluctuations in phylogenetic integration, thus influencing differential rates of skull-shape evolution in these two clades.
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Data supporting phylogenetic reconstructions of the Neotropical clade Gymnotiformes.
Data in brief, 2016Co-Authors: Victor A. Tagliacollo, Claudio Oliveira, Maxwell J. Bernt, Jack M. Craig, James S. AlbertAbstract:Data is presented in support of model-based total evidence (MBTE) phylogenetic reconstructions of the Neotropical clade of Gymnotiformes "Model-based total evidence phylogeny of Neotropical electric knifefishes (Teleostei, Gymnotiformes)" (Tagliacollo et al., 2016) [1]). The MBTE phylogenies were inferred using a comprehensive dataset comprised of six genes (5277 bp) and 223 morphological characters for an ingroup taxon sample of 120 of 218 valid species and 33 of the 34 extant genera. The data in this article include primer sequences for gene amplification and sequencing, voucher information and GenBank accession numbers, descriptions of morphological characters, morphological synapomorphies for the recognized clades of Gymnotiformes, a supermatrix comprised of concatenated molecular and morphological data, and computer scripts to replicate MBTE inferences. We also included here Maximum-likelihood and Bayesian topologies, which support two main gymnotiform clades: Gymnotidae and Sternopygoidei, the latter comprised of Rhamphichthyoidea (Rhamphichthyidae+Hypopomidae) and Sinusoidea (Sternopygidae+Apteronotidae).
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A New Species of Gymnorhamphichthys (Gymnotiformes
2011Co-Authors: Tiago P. Carvalho, Cristiane S. Ramos, James S. AlbertAbstract:pigment bars over the dorsal midline, extending between the nape and a vertical with the end of the anal fin, and sometimes reaching to or slightly below the lateral line. The new species differs from G. hypostomus in having 141–172 vs. 178–211 anal-fin rays; a shorter snout, preorbital distance 48.1–60.3% of head length (mean 54.6%) vs. 58.3–68.6% (mean 63.9%); a larger eye, diameter 5.7–9.0% of head length (mean 7.0%) vs. 3.3–5.9% (mean 4.3%); a longer distance from tip of snout to posterior nares, 17.1–22.0% of head length (mean 19.2%) vs. 11.2–17.1% (mean 13.8%); 7 vs. 9–13 displaced hemal spines; and 64–69 vs. 71–75 vertebrae to end of anal fin.