Diversification of Neotropical Freshwater Fishes Albert, James S; Tagliacollo, Victor A; Dagosta, Fernando
Annual review of ecology, evolution, and systematics,
11/2020, Volume:
51, Issue:
1
Journal Article
Peer reviewed
Open access
Neotropical freshwater fishes (NFFs) constitute the most diverse continental vertebrate fauna on Earth, with more than 6,200 named species compressed into an aquatic footprint <0.5% of the total ...regional land-surface area and representing the greatest phenotypic disparity and functional diversity of any continental ichthyofauna. Data from the fossil record and time-calibrated molecular phylogenies indicate that most higher taxa (e.g., genera, families) diversified relatively continuously through the Cenozoic, across broad geographic ranges of the South American platform. Biodiversity data for most NFF clades support a model of continental radiation rather than adaptive radiation, in which speciation occurs mainly in allopatry, and speciation and adaptation are largely decoupled. These radiations occurred under the perennial influence of river capture and sea-level oscillations, which episodically fragmented and merged portions of adjacent river networks. The future of the NFF fauna into the Anthropocene is uncertain, facing numerous threats at local, regional, and continental scales.
ABSTRACT We review geological evidence on the origin of the modern transcontinental Amazon River, and the paleogeographic history of riverine connections among the principal sedimentary basins of ...northern South America through the Neogene. Data are reviewed from new geochronological datasets using radiogenic and stable isotopes, and from traditional geochronological methods, including sedimentology, structural mapping, sonic and seismic logging, and biostratigraphy. The modern Amazon River and the continental-scale Amazon drainage basin were assembled during the late Miocene and Pliocene, via some of the largest purported river capture events in Earth history. Andean sediments are first recorded in the Amazon Fan at about 10.1-9.4 Ma, with a large increase in sedimentation at about 4.5 Ma. The transcontinental Amazon River therefore formed over a period of about 4.9-5.6 million years, by means of several river capture events. The origins of the modern Amazon River are hypothesized to be linked with that of mega-wetland landscapes of tropical South America (e.g. várzeas, pantanals, seasonally flooded savannahs). Mega-wetlands have persisted over about 10% northern South America under different configurations for >15 million years. Although the paleogeographic reconstructions presented are simplistic and coarse-grained, they are offered to inspire the collection and analysis of new sedimentological and geochronological datasets.
RESUMO Este trabalho é uma revisão das evidências geológicas sobre a origem do moderno rio Amazonas transcontinental, e a história paleogeográfica das conexões ribeirinhas entre as principais bacias sedimentares do norte da América do Sul durante o Neógeno. São revisados novos conjuntos de dados geocronológicos usando isótopos radiogênicos e estáveis, e de métodos geocronológicos tradicionais, incluindo sedimentologia, mapeamento estrutural, exploração sísmica e bioestratigrafia. O atual rio Amazonas e sua bacia continental se formaram durante o final do Mioceno e do Plioceno, através de alguns dos maiores eventos de captura de rio na história da Terra. Os sedimentos andinos são registrados pela primeira vez no leque fluvial do Amazonas por volta de 10,1-9,4 Ma, com um grande aumento na sedimentação a cerca de 4,5 Ma. O rio Amazonas transcontinental, portanto, se formou durante um período de cerca de 4,9 a 5,6 milhões de anos, por meio de vários eventos de captura de rios. Acredita-se que as origens do moderno rio Amazonas estejam ligadas às paisagens de inundação da América do Sul tropical (por exemplo, várzeas, pantanais, savanas sazonalmente inundadas). As áreas pantanosas persistiram em cerca de 10% do norte da América do Sul sob diferentes configurações por mais de 15 milhões de anos. Embora as reconstruções paleogeográficas apresentadas sejam simplistas, elas são oferecidas para inspirar a coleta e análise de novos conjuntos de dados sedimentológicos e geocronológicos.
The fish faunas of continental South and Central America constitute one of the greatest concentrations of aquatic diversity on Earth, consisting of about 10 percent of all living vertebrate species. ...Historical Biogeography of Neotropical Freshwater Fishes explores the evolutionary origins of this unique ecosystem. The chapters address central themes in the study of tropical biodiversity: why is the Amazon basin home to so many distinct evolutionary lineages? What roles do ecological specialization, speciation, and extinction play in the formation of regional assemblages? How do dispersal barriers contribute to isolation and diversification? Focusing on whole faunas rather than individual taxonomic groups, this volume shows that the area's high regional diversity is not the result of recent diversification in lowland tropical rainforests. Rather, it is the product of species accumulating over tens of millions of years and across a continental arena.
Freshwater ecosystems provide irreplaceable services for both nature and society. The quality and quantity of freshwater affect biogeochemical processes and ecological dynamics that determine ...biodiversity, ecosystem productivity, and human health and welfare at local, regional and global scales. Freshwater ecosystems and their associated riparian habitats are amongst the most biologically diverse on Earth, and have inestimable economic, health, cultural, scientific and educational values. Yet human impacts to lakes, rivers, streams, wetlands and groundwater are dramatically reducing biodiversity and robbing critical natural resources and services from current and future generations. Freshwater biodiversity is declining rapidly on every continent and in every major river basin on Earth, and this degradation is occurring more rapidly than in terrestrial ecosystems. Currently, about one third of all global freshwater discharges pass through human agricultural, industrial or urban infrastructure. About one fifth of the Earth’s arable land is now already equipped for irrigation, including all the most productive lands, and this proportion is projected to surpass one third by midcentury to feed the rapidly expanding populations of humans and commensal species, especially poultry and ruminant livestock. Less than one fifth of the world’s preindustrial freshwater wetlands remain, and this proportion is projected to decline to under one tenth by midcentury, with imminent threats from water transfer megaprojects in Brazil and India, and coastal wetland drainage megaprojects in China. The Living Planet Index for freshwater vertebrate populations has declined to just one third that of 1970, and is projected to sink below one fifth by midcentury. A linear model of global economic expansion yields the chilling prediction that human utilization of critical freshwater resources will approach one half of the Earth’s total capacity by midcentury. Although the magnitude and growth of the human freshwater footprint are greater than is generally understood by policy makers, the news media, or the general public, slowing and reversing dramatic losses of freshwater species and ecosystems is still possible. We recommend a set of urgent policy actions that promote clean water, conserve watershed services, and restore freshwater ecosystems and their vital services. Effective management of freshwater resources and ecosystems must be ranked amongst humanity’s highest priorities.
The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a grave threat to public health and the global economy. SARS-CoV-2 is closely related to the more ...lethal but less transmissible coronaviruses SARS-CoV-1 and Middle East respiratory syndrome coronavirus (MERS-CoV). Here, we have carried out comparative viral-human protein-protein interaction and viral protein localization analyses for all three viruses. Subsequent functional genetic screening identified host factors that functionally impinge on coronavirus proliferation, including Tom70, a mitochondrial chaperone protein that interacts with both SARS-CoV-1 and SARS-CoV-2 ORF9b, an interaction we structurally characterized using cryo-electron microscopy. Combining genetically validated host factors with both COVID-19 patient genetic data and medical billing records identified molecular mechanisms and potential drug treatments that merit further molecular and clinical study.
Neurodevelopmental conditions commonly coexist in children, but compared to adults, childhood multimorbidity attracts less attention in research and clinical practice. We previously reported that ...children treated for attention deficit hyperactivity disorder (ADHD) and depression have more school absences and exclusions, additional support needs, poorer attainment, and increased unemployment. They are also more likely to have coexisting conditions, including autism and intellectual disability. We investigated prevalence of neurodevelopmental multimorbidity (≥2 conditions) among Scottish schoolchildren and their educational outcomes compared to peers.
We retrospectively linked 6 Scotland-wide databases to analyse 766,244 children (390,290 50.9% boys; 375,954 49.1% girls) aged 4 to 19 years (mean = 10.9) attending Scottish schools between 2009 and 2013. Children were distributed across all deprivation quintiles (most to least deprived: 22.7%, 20.1%, 19.3%, 19.5%, 18.4%). The majority (96.2%) were white ethnicity. We ascertained autism spectrum disorder (ASD) and intellectual disabilities from records of additional support needs and ADHD and depression through relevant encashed prescriptions. We identified neurodevelopmental multimorbidity (≥2 of these conditions) in 4,789 (0.6%) children, with ASD and intellectual disability the most common combination. On adjusting for sociodemographic (sex, age, ethnicity, deprivation) and maternity (maternal age, maternal smoking, sex-gestation-specific birth weight centile, gestational age, 5-minute Apgar score, mode of delivery, parity) factors, multimorbidity was associated with increased school absenteeism and exclusion, unemployment, and poorer exam attainment. Significant dose relationships were evident between number of conditions (0, 1, ≥2) and the last 3 outcomes. Compared to children with no conditions, children with 1 condition, and children with 2 or more conditions, had more absenteeism (1 condition adjusted incidence rate ratio IRR 1.28, 95% CI 1.27-1.30, p < 0.001 and 2 or more conditions adjusted IRR 1.23, 95% CI 1.20-1.28, p < 0.001), greater exclusion (adjusted IRR 2.37, 95% CI 2.25-2.48, p < 0.001 and adjusted IRR 3.04, 95% CI 2.74-3.38, p < 0.001), poorer attainment (adjusted odds ratio OR 3.92, 95% CI 3.63-4.23, p < 0.001 and adjusted OR 12.07, 95% CI 9.15-15.94, p < 0.001), and increased unemployment (adjusted OR 1.57, 95% CI 1.49-1.66, p < 0.001 and adjusted OR 2.11, 95% CI 1.83-2.45, p < 0.001). Associations remained after further adjustment for comorbid physical conditions and additional support needs. Coexisting depression was the strongest driver of absenteeism and coexisting ADHD the strongest driver of exclusion. Absence of formal primary care diagnoses was a limitation since ascertaining depression and ADHD from prescriptions omitted affected children receiving alternative or no treatment and some antidepressants can be prescribed for other indications.
Structuring clinical practice and training around single conditions may disadvantage children with neurodevelopmental multimorbidity, who we observed had significantly poorer educational outcomes compared to children with 1 condition and no conditions.
Hearing loss is associated with increased cognitive decline and incident dementia in older adults. We aimed to investigate whether a hearing intervention could reduce cognitive decline in cognitively ...healthy older adults with hearing loss.
The ACHIEVE study is a multicentre, parallel-group, unmasked, randomised controlled trial of adults aged 70–84 years with untreated hearing loss and without substantial cognitive impairment that took place at four community study sites across the USA. Participants were recruited from two study populations at each site: (1) older adults participating in a long-standing observational study of cardiovascular health (Atherosclerosis Risk in Communities ARIC study), and (2) healthy de novo community volunteers. Participants were randomly assigned (1:1) to a hearing intervention (audiological counselling and provision of hearing aids) or a control intervention of health education (individual sessions with a health educator covering topics on chronic disease prevention) and followed up every 6 months. The primary endpoint was 3-year change in a global cognition standardised factor score from a comprehensive neurocognitive battery. Analysis was by intention to treat. This trial was registered at ClinicalTrials.gov, NCT03243422.
From Nov 9, 2017, to Oct 25, 2019, we screened 3004 participants for eligibility and randomly assigned 977 (32·5%; 238 24% from ARIC and 739 76% de novo). We randomly assigned 490 (50%) to the hearing intervention and 487 (50%) to the health education control. The cohort had a mean age of 76·8 years (SD 4·0), 523 (54%) were female, 454 (46%) were male, and most were White (n=858 88%). Participants from ARIC were older, had more risk factors for cognitive decline, and had lower baseline cognitive scores than those in the de novo cohort. In the primary analysis combining the ARIC and de novo cohorts, 3-year cognitive change (in SD units) was not significantly different between the hearing intervention and health education control groups (–0·200 95% CI –0·256 to –0·144 in the hearing intervention group and –0·202 –0·258 to –0·145 in the control group; difference 0·002 –0·077 to 0·081; p=0·96). However, a prespecified sensitivity analysis showed a significant difference in the effect of the hearing intervention on 3-year cognitive change between the ARIC and de novo cohorts (pinteraction=0·010). Other prespecified sensitivity analyses that varied analytical parameters used in the total cohort did not change the observed results. No significant adverse events attributed to the study were reported with either the hearing intervention or health education control.
The hearing intervention did not reduce 3-year cognitive decline in the primary analysis of the total cohort. However, a prespecified sensitivity analysis showed that the effect differed between the two study populations that comprised the cohort. These findings suggest that a hearing intervention might reduce cognitive change over 3 years in populations of older adults at increased risk for cognitive decline but not in populations at decreased risk for cognitive decline.
US National Institutes of Health.
Looked after children are defined as children who are in the care of their local authority. Previous studies have reported that looked after children have poorer mental and physical health, increased ...behavioural problems, and increased self-harm and mortality compared to peers. They also experience poorer educational outcomes, yet population-wide research into the latter is lacking, particularly in the United Kingdom. Education and health share a bidirectional relationship; therefore, it is important to dually investigate both outcomes. Our study aimed to compare educational and health outcomes for looked after children with peers, adjusting for sociodemographic, maternity, and comorbidity confounders.
Linkage of 9 Scotland-wide databases, covering dispensed prescriptions, hospital admissions, maternity records, death certificates, annual pupil census, examinations, school absences/exclusions, unemployment, and looked after children provided retrospective data on 715,111 children attending Scottish schools between 2009 and 2012 (13,898 1.9% looked after). Compared to peers, 13,898 (1.9%) looked after children were more likely to be absent (adjusted incidence rate ratio AIRR 1.27, 95% confidence interval CI 1.24 to 1.30) and excluded (AIRR 4.09, 95% CI 3.86 to 4.33) from school, have special educational need (SEN; adjusted odds ratio AOR 3.48, 95% CI 3.35 to 3.62) and neurodevelopmental multimorbidity (AOR 2.45, 95% CI 2.34 to 2.57), achieve the lowest level of academic attainment (AOR 5.92, 95% CI 5.17 to 6.78), and be unemployed after leaving school (AOR 2.12, 95% CI 1.96 to 2.29). They were more likely to require treatment for epilepsy (AOR 1.50, 95% CI 1.27 to 1.78), attention deficit hyperactivity disorder (ADHD; AOR 3.01, 95% CI 2.76 to 3.27), and depression (AOR 1.90, 95% CI 1.62 to 2.22), be hospitalised overall (adjusted hazard ratio AHR 1.23, 95% CI 1.19 to 1.28) for injury (AHR 1.80, 95% CI 1.69 to 1.91) and self-harm (AHR 5.19, 95% CI 4.66 to 5.78), and die prematurely (AHR 3.21, 95% CI 2.16 to 4.77). Compared to children looked after at home, children looked after away from home had less absenteeism (AIRR 0.35, 95% CI 0.33 to 0.36), less exclusion (AIRR 0.63, 95% CI 0.56 to 0.71), less unemployment (AOR 0.53, 95% CI 0.46 to 0.62), and better attainment (AIRR 0.31, 95% CI 0.23 to 0.40). Therefore, among those in care, being cared for away from home appeared to be a protective factor resulting in better educational outcomes. The main limitations of this study were lack of data on local authority care preschool or before 2009, total time spent in care, and age of first contact with social care.
Looked after children had poorer health and educational outcomes than peers independent of increased neurodevelopmental conditions and SEN. Further work is required to understand whether poorer outcomes relate to reasons for entering care, including maltreatment and adverse childhood events, neurodevelopmental vulnerabilities, or characteristics of the care system.
The main objectives of this study are estimate a species-dense, time-calibrated molecular phylogeny of Hypoptopomatinae, Neoplecostominae, and Otothyrinae, which together comprise a group of armoured ...catfishes that is widely distributed across South America, to place the origin of major clades in time and space, and to demonstrate the role of river capture on patterns of diversification in these taxa. We used maximum likelihood and Bayesian methods to estimate a time-calibrated phylogeny of 115 loricariid species, using three mitochondrial and one nuclear genes to generate a matrix of 4,500 base pairs, and used parametric biogeographic analyses to estimate ancestral geographic ranges and to infer the effects of river capture events on the geographic distributions of these taxa. Our analysis recovered Hypoptopomatinae, Neoplecostominae, and Otothyrinae as monophyletic with strong statistical support, and Neoplecostominae as more closely related to Otothyrinae than to Hypoptopomatinae. Our time-calibrated phylogeny and ancestral-area estimations indicate an origin of Hypoptopomatinae, Neoplecostominae, and Otothyrinae during the Lower Eocene in the Atlantic Coastal Drainages, from which it is possible to infer several dispersal events to adjacent river basins during the Neogene. In conclusion we infer a strong influence of river capture in: (1) the accumulation of modern clade species-richness values; (2) the formation of the modern basin-wide species assemblages, and (3) the presence of many low-diversity, early-branching lineages restricted to the Atlantic Coastal Drainages. We further infer the importance of headwater stream capture and marine transgressions in shaping patterns in the distributions of Hypoptopomatinae, Neoplecostominae and Otothyrinae throughout South America.
Evolutionary transitions across abiotic gradients can occur among habitats at multiple spatial scales, and among taxa and biotas through a range of ecological and evolutionary time frames. Two ...diverse groups of electric fishes, Neotropical Gymnotiformes and Afrotropical Mormyroidea, offer interesting examples of potentially convergent evolution in aspects of morphological, physiological, and life history traits. We examined biogeographical, morphological, and functional patterns across these two groups to assess the degree of convergence in association with abiotic environmental variables. While there are superficial similarities across the groups and continents, we found substantially more differences in terms of habitat occupancy, electric signal diversity, and morphological disparity. These differences likely correlate to differences in biogeographical histories across the Neotropics and Afrotropics, biotic factors associated with aquatic life and electric signals, and sampling issues plaguing both groups. Additional research and sampling are required to make further inferences about how electric fishes transition throughout diverse freshwater habitats across both microevolutionary and macroevolutionary scales. We find little evidence that abiotic gradients in the freshwater habitat medium have driven convergent evolution of functional traits in these two continental radiations of electric fishes.
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