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590 results for “Neotropical fish”
FIGURE 4 in Areas of endemism for Anablepidae (Teleostei: Cyprinodontiformes): A monophyletic family of freshwater fishes in the Neotropics
FIGURE 4. Consensus areas of endemism (CAs) delimited for Anablepidae by endemicity analysis with grid size of 1.5º.
Riverscape properties contribute to the origin and structure of a hybrid zone in a Neotropical freshwater fish
Understanding the structure of hybrid zones provides valuable insights about species boundaries and speciation, such as the evolution of barriers to gene flow and the strength of selection. In river networks, studying evolutionary processes in hybrid zones can be especially challenging, given the influence of past and current river properties along with biological species-specific traits. Here, we suggest that a natural hybrid zone between two divergent lineages of the sexually dimorphic Neotropical fish Nematocharax venustus was probably established by secondary contact as a result of a river capture event between the Contas and Pardo river basins. This putative river capture is supported by hydrogeological evidence of elbows of capture, wind gaps, and geological faults. The morphological (color pattern) and genetic (mtDNA and RADseq) variation reveal a clinal transition between parental lineages along the main river, with predominance of F2 hybrids at the centre of the hybrid zone, absence of early generation backcrosses, and different levels of hybridization in the tributaries. We highlight that different sources of information are crucial for understanding how the riverscape spatial history influences the connectivity between and within rivers systems and, consequently, the dynamics of gene flow between freshwater lineages/species.
Data from: Testing for ancient adaptive radiations in Neotropical cichlid fishes
Most contemporary studies of adaptive radiation focus on relatively recent and geographically restricted clades. It is less clear whether diversification of ancient clades spanning entire continents is consistent with adaptive radiation. We used novel fossil calibrations to generate a chronogram of Neotropical cichlid fishes and to test whether patterns of lineage and morphological diversification are congruent with hypothesized adaptive radiations in South and Central America. We found that diversification in the Neotropical cichlid clade and the highly diverse tribe Geophagini was consistent with diversity-dependent, early bursts of divergence followed by decreased rates of lineage accumulation. South American Geophagini underwent early rapid differentiation in body shape, expanding into novel morphological space characterized by elongate-bodied predators. Divergence in head-shape attributes associated with trophic specialization evolved under strong adaptive constraints in all Neotropical cichlid clades. The South American Cichlasomatini followed patterns consistent with constant rates of morphological divergence. Although morphological diversification in South American Heroini was limited, Eocene invasion of Central American habitats was followed by convergent diversification mirroring variation observed in Geophagini. Diversification in Neotropical cichlids was influenced by the early adaptive radiation of Geophagini, which potentially limited differentiation in other cichlid clades.
Data from: Assessing species boundaries using multilocus species delimitation in a morphologically conserved group of Neotropical freshwater fishes, the Poecilia sphenops species complex (Poeciliidae)
Accurately delimiting species is fundamentally important for understanding species diversity and distributions and devising effective strategies to conserve biodiversity. However, species delimitation is problematic in many taxa, including 'non-adaptive radiations' containing morphologically cryptic lineages. Fortunately, coalescent-based species delimitation methods hold promise for objectively estimating species limits in such radiations, using multilocus genetic data. Using coalescent-based approaches, we delimit species and infer evolutionary relationships in a morphologically conserved group of Central American freshwater fishes, the Poecilia sphenops species complex. Phylogenetic analyses of multiple genetic markers (sequences of two mitochondrial DNA genes and five nuclear loci) from 10/15 species and genetic lineages recognized in the group support the P. sphenops species complex as monophyletic with respect to outgroups, with eight mitochondrial 'major-lineages' diverged by ≥2% pairwise genetic distances. From general mixed Yule-coalescent models, we discovered (conservatively) 10 species within our concatenated mitochondrial DNA dataset, 9 of which were strongly supported by subsequent multilocus Bayesian species delimitation and species tree analyses. Results suggested species-level diversity is underestimated or overestimated by at least ~15% in different lineages in the complex. Nonparametric statistics and coalescent simulations indicate genealogical discordance among our gene tree results has mainly derived from interspecific hybridization in the nuclear genome. However, mitochondrial DNA show little evidence for introgression, and our species delimitation results appear robust to effects of this process. Overall, our findings support the utility of combining multiple lines of genetic evidence and broad phylogeographical sampling to discover and validate species using coalescent-based methods. Our study also highlights the importance of testing for hybridization versus incomplete lineage sorting, which aids inference of not only species limits but also evolutionary processes influencing genetic diversity.
Data from: Selection is stronger in early-versus-late stages of divergence in a Neotropical livebearing fish
How selection acts to drive trait evolution at different stages of divergence is of fundamental importance in our understanding of the origins of biodiversity. Yet, most studies have focused on a single point along an evolutionary trajectory. Here, we provide a case study evaluating the strength of divergent selection acting on life-history traits at early-versus-late stages of divergence in Brachyrhaphis fishes. We find that the difference in selection is stronger in the early-diverged population than the late-diverged population, and that trait differences acquired early are maintained over time.
Data from: Unique evolutionary trajectories in repeated adaptation to hydrogen sulphide-toxic habitats of a neotropical fish (Poecilia mexicana)
Replicated ecological gradients are prime systems to study processes of molecular evolution underlying ecological divergence. Here, we investigated the repeated adaptation of the neotropical fish Poecilia mexicana to habitats containing toxic hydrogen sulphide (H2S) and compared two population pairs of sulphide-adapted and ancestral fish by sequencing population pools of >200 individuals (Pool-Seq). We inferred the evolutionary processes shaping divergence and tested the hypothesis of increase of parallelism from SNPs to molecular pathways. Coalescence analyses showed that the divergence occurred in the face of substantial bidirectional gene flow. Population divergence involved many short, widely dispersed regions across the genome. Analyses of allele frequency spectra suggest that differentiation at most loci was driven by divergent selection, followed by a selection-mediated reduction of gene flow. Reconstructing allelic state changes suggested that selection acted mainly upon de novo mutations in the sulphide-adapted populations. Using a corrected Jaccard index to quantify parallel evolution, we found a negligible proportion of statistically significant parallel evolution of Jcorr = 0.0032 at the level of SNPs, divergent genome regions (Jcorr = 0.0061) and genes therein (Jcorr = 0.0091). At the level of metabolic pathways, the overlap was Jcorr = 0.2545, indicating increasing parallelism with increasing level of biological integration. The majority of pathways contained positively selected genes in both sulphide populations. Hence, adaptation to sulphidic habitats necessitated adjustments throughout the genome. The largely unique evolutionary trajectories may be explained by a high proportion of de novo mutations driving the divergence. Our findings favour Gould's view that evolution is often the unrepeatable result of stochastic events with highly contingent effects.
FIGURE 5 in Gymnotus ardilai: a new species of Neotropical electric fish (Ostariophysi: Gymnotidae) from the Rio Magdalena Basin of Colombia
FIGURE 5. Map of Colombia illustrating the type locality () of Gymnotus ardilai and 1: Bucaramanga city; 2: Pie de Cuesta; 3: Girón.
FIGURE 2. Gymnotus ardilai. Paratypes IAvHP 4001 in Gymnotus ardilai: a new species of Neotropical electric fish (Ostariophysi: Gymnotidae) from the Rio Magdalena Basin of Colombia
FIGURE 2. Gymnotus ardilai. Paratypes IAvHP 4001, males, (A) 219.2 mm TL, (B) 329 mm TL. Lateral view.
FIGURES 43–52 in Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus
FIGURES 43–52. Male genital complex (MGC) and haptor armature of 5 species of Characithecium. 43–44. C. chascomusensis n. comb. 43. MGC, ventral view. 44. haptor, ventral view. 45–46.C. longianchoratum n. sp. 45. MGC, dorsal view. 46. haptor, ventral view. 47–48. C. robustum n. sp. 47. MGC, dorsal view. 48. haptor, ventral view. 49–50. C. quadratum n. sp. 49. MGO, dorsal view. 50. haptor, ventral view. 51–52.C. chelatum n. sp. 51. MGC, dorsal view. 52. haptor, ventral view. Scale bars: 43, 45, 47, 49, 51 = 10 µm; 44, 46, 48, 50, 52 = 20 µm.
FIGURES 27–34. Characithecium quadratum n in Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus
FIGURES 27–34. Characithecium quadratum n. sp. 27. whole mount, ventral view. 28. male genital complex, ventral view. 29. vagina, ventral view. 30. ventral bar. 31. dorsal bar. 32. ventral anchor. 33. dorsal anchor. 34. hook. Scale bars: 27= 125 Μm; 28= 10 Μm; 29–34= 20 Μm.
FIGURES 1–8. Characithecium chascomusensis n in Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus
FIGURES 1–8. Characithecium chascomusensis n. comb. (Suriano 1981). 1.whole mount, ventral view. 2. copulatory complex, ventral view. 3. vagina, ventral view. 4. ventral bar. 5. dorsal bar. 6. ventral anchor. 7. dorsal anchor. 8. hook. Scale bars: 1 = 50 Μm; 2 = 10 Μm; 3–8 = 20 Μm.
FIGURES 18–26.Characithecium robustum n in Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus
FIGURES 18–26.Characithecium robustum n. sp. 18. whole mount, ventral view. 19. male genital complex, ventral view. 20. Egg. 21. vagina, ventral view. 22. ventral bar. 23. dorsal bar. 24. ventral anchor. 25. dorsal anchor. 26. hook. Scale bars: 18 = 125 Μm; 19 = 10 Μm;20–26 = 20 Μm.
FIGURES 35–42.Characithecium chelatum n in Characithecium (Monogenoidea: Dactylogyridae) parasitic on the Neotropical fish Oligosarcus jenynsii (Teleostei: Characidae) from the Pampasic region, Argentina, with the emendation of the genus
FIGURES 35–42.Characithecium chelatum n. sp. 35. whole mount, ventral view. 36. male genital complex, ventral view. 37. vagina, ventral view. 38. ventral bar. 39. dorsal bar. 40. ventral anchor. 41.dorsal anchor. 42. hook. Scale bars: 35 = 50 Μm; 36 = 10 Μm; 37–42 = 20 Μm.
FIGURE 6. Serrapinnus kriegi, UFRGS 20135, 20.2 in Inventory of the freshwater fishes from a densely collected area in South America — a case study of the current knowledge of Neotropical fish diversity
FIGURE 6. Serrapinnus kriegi, UFRGS 20135, 20.2 mm SL, rio Ibicuí, tributary of the rio Uruguay; new record for the state of Rio Grande do Sul.
FIGURE 14 in Inventory of the freshwater fishes from a densely collected area in South America — a case study of the current knowledge of Neotropical fish diversity
FIGURE 14. Approximate localities of collection of expeditions made in the second half of the XIX Century and beginning of XX Century in Rio Grande do Sul State: Reinhold F. Hensel (1863-1866, pink); Emperor Dom Pedro II (1865-1866, red); Herman von Ihering (1880-1892, blue); Herbert H. Smith (1882, green); John D. Haseman (1909, yellow); Ernst Garbe (1914, black); Herman Kleerekoper (1941, white).
FIGURE 12 in Inventory of the freshwater fishes from a densely collected area in South America — a case study of the current knowledge of Neotropical fish diversity
FIGURE 12. Cumulative number of fish species known to occur in Rio Grande do Sul State grouped by decade according to the year of description.
FIGURE 9 in Inventory of the freshwater fishes from a densely collected area in South America — a case study of the current knowledge of Neotropical fish diversity
FIGURE 9. Total number of species and new species per hydrographic basin, Rio Grande do Sul State, Brazil.
FIGURE 2 in Inventory of the freshwater fishes from a densely collected area in South America — a case study of the current knowledge of Neotropical fish diversity
FIGURE 2. Sampling localities of fishes in the Rio Grande do Sul State catalogued and georeferenced in the collections of the Museu de Ciências Naturais, Fundação Zoobotânica do Rio Grande do Sul (MCN), Museu de Ciências e Tecnologia, Pontifícia Universidade Católica do Rio Grande do Sul (MCP), and Departamento de Zoologia, Universidade Federal do Rio Grande do Sul (UFRGS).
FIGURE 13 in Inventory of the freshwater fishes from a densely collected area in South America — a case study of the current knowledge of Neotropical fish diversity
FIGURE 13. Maximum, mean and minimum body size (standard length in mm) of species known to occur in Rio Grande do Sul State, grouped by decade according to the year of description.
FIGURE 5 in Inventory of the freshwater fishes from a densely collected area in South America — a case study of the current knowledge of Neotropical fish diversity
FIGURE 5. Ctenobrycon cf. alleni, UFRGS 20147, 42.3 mm SL, rio Ibicuí, tributary of the rio Uruguay; new record for the state of Rio Grande do Sul.
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
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DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.