52 research outputs found
Diversificação do complexo Allobates femoralis (Anura, Dendrobatidae) em florestas da Amazônia brasileira: desvendando padrões atuais e históricos.
In this study, I analyze aspects of the diversity and evolution of a group of
phylogenetically related anuran species, which are widely distributed along the Amazon
basin, and which have been historically recognized as belonging to a single taxon:
Allobates femoralis. The first chapter addresses the systematic relationships between
several allopatric populations of this group and formalizes the recognition and description
of a new species: Allobates hodli. It also highlights the occurrence of additional
monophyletic lineages, which present particular acoustic and morphological phenotypes,
and are indicated as potential cryptic species. In the second chapter, I evaluate the effect
of the Madeira River on the genetic, morphological, and acoustic differentiation between
A. femoralis populations distributed along both interfluves, applying phylogeographic
analyses in order to verify the congruence between observed differentiation patterns and
those expected if the Madeira River has functioned as a vicariant barrier since its origin.
Phylogenetic and population analyses based on mitochondrial molecular markers
suggests patterns that are coincident with the hypothesis that the Madeira River channel
represents a historical barrier causing the isolation between populations from opposite
riverbanks. However, the effectiveness of the river as a vicariant barrier is variable along
its course, and possible events of dispersal between riverbanks are reported for localities
between its middle and upper course. Morphology and calls of populations sampled on
the same interfluve are not more similar to each other in when compared to populations
sampled on the opposite riverbank, suggesting that differentiation of phenotypic
characters is influenced by additional evolutionary mechanisms. In the third chapter, I
present the genetic characterization of a contact zone between A. femoralis and A. hodli,
located on the upper Madeira River. Analyses of mitochondrial and microsatellite
molecular markers suggest that natural hybridization between the two species is more
frequent along the geographic central line of the contact zone, decaying abruptly less than
two kilometers downstream and upstream of this area. Genetic diversity estimates
measured at sites adjacent to the contact zone support the existence of selection against
hybrids originating from direct crosses between parental individuals belonging to the two
species.Neste estudo, analiso aspectos da diversidade e evolução de um grupo de espécies
de anuros filogeneticamente relacionados, amplamente distribuídos na bacia Amazônica e
historicamente reconhecidos como um único táxon: Allobates femoralis. O primeiro
capítulo aborda as relações sistemáticas entre diversas populações alopátricas deste grupo
e formaliza o reconhecimento e descrição de uma nova espécie: Allobates hodli. Também
é apontada a ocorrência de outras linhagens monofiléticas, possuidoras de fenótipos
acústicos e morfológicos característicos, indicadas como potenciais espécies crípticas. No
segundo capítulo, avalio o efeito do rio Madeira sobre a diferenciação genética,
morfológica e acústica de populações de A. femoralis distribuídas ao longo de seus
interflúvios, além de aplicar análises filogeográficas para verificar a congruência entre os
padrões de diferenciação observados e os padrões esperados caso o rio Madeira tenha
funcionado como uma barreira vicariante desde sua formação. Análises filogenéticas e
populacionais baseadas em marcadores moleculares mitocondriais apontam padrões
condizentes com a hipótese de que o leito do rio Madeira represente uma barreira
histórica proporcionando o isolamento entre populações de margens opostas. Porém, a
eficácia do rio como barreira vicariante é variável ao longo de seu curso, sendo
reportados prováveis eventos de dispersão entre margens em pontos entre o médio e o
alto curso do rio. Populações amostradas em um mesmo interflúvio não possuem
morfologia ou vocalizações mais similares entre si do que quando comparadas a
populações amostradas na margem oposta, indicando que a diferenciação de caracteres
fenotípicos é influenciada por outros mecanismos evolutivos. No terceiro capítulo,
apresento a caracterização genética de uma zona de contato entre A. femoralis e A. hodli,
localizada no alto rio Madeira. A análise de marcadores moleculares mitocondriais e
microssatélites sugerem que hibridização natural entre as duas espécies é mais freqüente
na linha central geográfica da zona de contato, decaindo abruptamente em um raio
inferior a dois quilômetros à jusante e à montante desta área. Estimativas de diversidade
genética obtidos em áreas adjacentes à zona de contato suportam a existência de seleção
contra híbridos oriundos do cruzamento direto entre indivíduos parentais pertencentes às
duas espécies
Distribution extension of Hyalinobatrachium cappellei (van Lidth de Jeude, 1904) (Anura: Centrolenidae) across Central Amazonia
We report the occurrence of the centrolenid frog Hyalinobatrachium cappellei in Careiro, Amazonas, Brazil (Central Amazonia). Our records reduce a gap of approximately 1,500 km between the closest known records for this glassfrog, and confirm H. cappellei as geographically widespread in the Amazon Basin. © 2012 Check List and Authors
Predation of Ameivula ocellifera (Squamata, Teiidae) by Oxybelis aeneus (Squamata, Colubridae), in the Caatinga, Northeastern Brazil, including a list of saurophagy by this snake
Familial hypercholesterolaemia in children and adolescents from 48 countries: a cross-sectional study
Background: Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies. Methods: For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia. Findings: Of 63 093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11 476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11 848 individuals. Median age at registry entry was 9·6 years (IQR 5·8-13·2). 10 099 (89·9%) of 11 235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10 428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05-6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50-75% of children and adolescents with familial hypercholesterolaemia not being identified. Interpretation: Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life
Divergência acústica e morfológica em populações de Allobates femoralis (Anura, Dendrobatidae) do alto Rio Madeira.
Since the 19th century, researchers have hypothesized that large Amazonian rivers function as barriers to dispersal. However, case studies using anurans detected no river effect to date in the region. This study aimed to determine the influence of the upper Madeira River on acoustic and morphological divergence patterns in populations of the dart-poison frog Allobates femoralis. Seventeen collecting sites were established in forested areas on both margins of the upper Madeira River, in the Brazilian State of Rondônia, where I recorded the advertisement calls, weights and external morphological variables of E. femoralis males. I encountered two very distinct morphotypes, which probably represent distinct taxa. One, with a 2-note advertisement call, occurs only on the left bank of the upper Madeira River, up to a parapatric contact zone with the second morphotype, where there are presently no apparent barriers to dispersal. The second morphotype, with a 4-note advertisement call, occurs on both sides of the river.
Multivariate analysis of variance (MANOVA) showed that, once the effects of body size, air temperature and distances between collecting sites have been removed, there are 3 distinct groups relative to vocalizations and morphology: Group 1: populations belonging to the 2-note call morphotype; Group 2: populations belonging to the 4-note
calls morphotype inhabiting the left riverbank; and Group 3: populations belonging to the 4-note calls morphotype inhabiting the right riverbank. Differences between relative
finger lengths and body condition among samples of the 4-note morph corroborated those results. We conclude that there is evidence for the upper Madeira River delimiting
distinct populations. However, at least one population sample included in the acoustic analysis and another included in the morphological analysis did not correspond to the general divergence pattern, suggesting that the river effect has not been sufficient to result in fixed differences between populations of A. femoralis on opposite riverbanks.
Therefore, besides the separation of population by the riverbed, geological features such as a limit between two geo-morphological units found on the left bank, are necessary to
explain the vocal and morphological divergence between the A. femoralis morphotypes found in this region.Desde o século XIX, pesquisadores investigam a hipótese de que os grandes rios amazônicos funcionam como barreiras à dispersão de animais. Entretanto, estudos de caso usando anuros não detectaram este efeito dos rios da região até o momento. Este estudo buscou avaliar a influência do alto Rio Madeira sobre a divergência acústica e morfológica do dendrobatídeo Allobates femoralis. Para isso, foram estabelecidas 17 áreas de coleta em ambas as margens do Rio Madeira, no Estado de Rondônia, onde registrei os cantos de anúncio, peso e variáveis morfológicas externas de machos.
Encontrei dois morfotipos distintos, que provavelmente representam táxons diferentes.
Um, com cantos de anúncio de 2 notas, ocorreu apenas na parte ocidental da margem esquerda do rio, alcançando uma zona de contato parapátrica com o segundo morfotipo,
onde atualmente não existem barreiras aparentes à dispersão. O segundo morfotipo, com cantos de 4 notas, ocorreu nos dois lados do rio. Análises de variância multivariadas
(MANOVA) mostraram que, mesmo considerados os efeitos do tamanho do corpo, temperatura do ar e distância entre áreas de coleta, existem 3 grupos distintos em relação a características acústicas do canto e morfologia: Grupo 1: populações pertencentes ao morfotipo com cantos de 2 notas; Grupo 2: populações pertencentes ao morfotipo de 4 notas da margem esquerda; e Grupo 3: populações do morfotipo de 4 notas da margem direita. Diferenças nos comprimentos relativos dos dedos palmares e fator de condição em amostras do morfotipo de 4 notas corroboraram esses resultados.
Concluí que existe evidência de que o alto Rio Madeira delimite populações distintas de A. femoralis. No entanto, uma população incluída nas análises acústicas e outra incluída
nas análises morfológicas não corresponderam ao padrão encontrado, sugerindo que o efeito do rio não foi suficiente para resultar em diferenças totalmente fixas entre
populações de margens opostas. Além da separação de populações pelo leito do rio, fatores geológicos como o limite entre dois domínios geo-morfológicos na margem
esquerda do alto Rio Madeira, parecem ser necessários para explicar a divergência vocal e morfológica entre os morfotipos de A. femoralis encontrados na região
A new species of nurse-frog (Aromobatidae, Allobates) from the Madeira River basin with a small geographic range
I describe the seventh species of nurse-frog (Allobates) from the Madeira River basin in Brazilian Amazonia. The new species is distinguished from similar congeneric species by its small body size (snout-to-vent length ranging between 14.0-14.7 mm in adult males and between 14.7-14.9 mm in adult females), by the absence of dark brown regular shapes (e.g. hourglass, "X" or polygon-like marks) on the dorsum, by the absence of transverse dark bars on the dorsal surface of the thigh, and by the light gray to white ventral surfaces, light to dark gray only on throat in live male and female specimens. Males have a distinctive advertisement call characterized by the emission of long (7-11 s) trills of short notes (0.04 s in average) with dominant frequency at 5.9-6.3 kHz and emission rate ranging between 6.7-8.7 notes/s. DNA barcode analyses based on a fragment of the 16S rDNA mitochondrial gene provides additional support to the recognition of the new taxon, which is probably distributed on the east riverbank of the Madeira River, in the interfluve between the Aripuanã and Ji-Paraná rivers. Copyright © 2016 Magnolia Press
FIGURE 8 in A new species of nurse-frog (Aromobatidae, Allobates) from the Madeira River basin with a small geographic range
FIGURE 8. Advertisement calls of Allobates bacurau´s holotype (INPA-H 35398), recorded at 25.2°C. Advertisement calls of A. bacurau are characterized by the emission of short notes is long trills. (A) Waveform (upper graph) and sonogram (lower graph) of a 12 s long note trill. (B) Detailed view of a 1 s long section of the same recording. Note ascending frequency modulation of notes
http://zoobank.org/urn:lsid:zoobank.org:pub:52938026-61EF-43C5-8159-3859A07139DB
www.mapress.com/zootaxa
- …