Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
Zootaxa ; 4433(3): 542-560, 2018 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-30313218

RESUMO

Two new species of Luciobarbus are described from the Mediterranean Sea basin in Morocco and Algeria. Their monophyly and phylogenetic placement are resolved by molecular analyses using two mitochondrial markers (cyt b and D-loop). Luciobarbus lanigarensis, new species, from the Tafna River drainage in Algeria and Morocco, is distinguished by having orange fins, a great predorsal length (52-59% SL) and a very long pectoral fin (79-90% HL). Luciobarbus numidiensis, new species, from the El-Kébir River drainage in Algeria, is distinguished by having a golden pectoral-fin margin, 43-47+1-3 lateral line scales and a very long anal-fin (19-23%).


Assuntos
Cyprinidae , Filogenia , África do Norte , Animais , Mar Mediterrâneo
2.
Zootaxa ; 4277(1): 32-50, 2017 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30308659

RESUMO

Cyprinids of the genus Luciobarbus are the most abundant and widespread fishes in most freshwater ecosystems in the Maghreb. In the Mediterranean basin of Morocco, Algeria and Tunisia, all species of Luciobarbus-with exception of L. guercifensis-are superficially very similar and are distinguished mostly by minor morphometric characters. Molecular characters distinguish all species well and nine species are recognised from the area, two of them described here. Luciobarbus chelifensis, from the Chelif River drainage in Algeria, is distinguished by having 41-43+1-2 lateral line scales and a very short anal fin (18-19% SL). Luciobarbus mascarensis, from the Macta River drainage in Algeria, is distinguished by having usually 41+1-2 lateral line scales, a long anal-fin (19-22%) and a short caudal peduncle (15-17% SL). An identification key is given for all African Mediterranean Luciobarbus species except for L. callensis and L. rifensis, which could not be distinguished.


Assuntos
Cyprinidae , Rios , Argélia , Animais , Marrocos , Tunísia
3.
C R Biol ; 339(2): 83-98, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26874458

RESUMO

Climatic variations during the Quaternary period had a considerable impact on landscapes and habitat fragmentation (rivers) in North Africa. These historical events can have significant consequences on the genetic structure of the populations. Indeed, geographically separated and genetically isolated populations tend to differentiate themselves through time, eventually becoming distinct lineages, allowing new species to emerge in later generations. The aim of the present study is to use genetic and morphological techniques to evaluate the major role of the Saalian glaciation (Middle Quaternary) in the establishment of the geographic space and in the evolution of the intraspecific genetic diversity, by tracing the demographic history of barbels belonging to the Luciobarbus pallaryi (Cyprinidae) species in the Guir Basin (Algeria). In this context, two populations, from two distinct and isolated sites, were studied. Analysis of the cytochrome b (cyt b) mitochondrial markers and of the "D-loop" control region has shown that the "upstream" and "downstream" Guir populations are genetically differentiated. The molecular analyses suggest that the upstream population was disconnected from this hydrographic system during the Saalian glaciation period of the Quaternary. Subsequently, it was isolated in the foggaras underground waters in the Great Western Erg, at approximately 320 000 years BP, creating, through a bottleneck effect, a new allopatric lineage referred to as "Adrar". Conversely, the high genetic diversity in the upstream Guir (Bechar) population suggests that the stock is globally in expansion. These barbels (n=52) were also examined with meristic, morphometric, osteological, and biological features. These data also reveal a complete discrimination between the two populations, with a remarkable and distinctive behavioural adaptation for the Adrar specimens: neoteny.


Assuntos
Evolução Biológica , Mudança Climática/história , Cyprinidae/anatomia & histologia , Cyprinidae/genética , Camada de Gelo , Argélia , Animais , Citocromos b/genética , Marcadores Genéticos , Variação Genética , História Antiga , Mitocôndrias/genética
4.
Mol Ecol ; 18(11): 2489-502, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19389172

RESUMO

The Pyrenean region exhibits high levels of endemism suggesting a major contribution to the phylogeography of European species. But, to date, the role of the Pyrenees and surrounding areas as a glacial refugium for temperate species remains poorly explored. In the current study, we investigated the biogeographic role of the Pyrenean region through the analyses of genetic polymorphism and morphology of a typical forest-dwelling small mammal, the bank vole (Myodes glareolus). Analyses of the mitochondrial cytochrome b gene and the third upper molar (M(3)) show a complex phylogeographic structure in the Pyrenean region with at least three distinct lineages: the Western European, Spanish and Basque lineages. The Basque lineage in the northwestern (NW) Pyrenees was identified as a new clearly differentiated and geographically localized bank vole lineage in Europe. The average M(3) shape of Basque bank voles suggests morphological differentiation but also restricted genetic exchanges with other populations. Our genetic and morphological results as well as palaeo-environmental and fossils records support the hypothesis of a new glacial refugium in Europe situated in the NW Pyrenees. The permissive microclimatic conditions that prevailed for a long time in this region may have allowed the survival of temperate species, including humans. Moreover, local differentiation around the Pyrenees is favoured by the opportunity for populations to track the shift of the vegetation belt in altitude rather than in latitude. The finding of the Basque lineage is in agreement with the high level of endemic taxa reported in the NW Pyrenees.


Assuntos
Arvicolinae/genética , Genética Populacional , Filogenia , Animais , Arvicolinae/anatomia & histologia , Citocromos b/genética , DNA Mitocondrial/genética , Europa (Continente) , Evolução Molecular , Geografia , Haplótipos , Polimorfismo Genético , Análise de Sequência de DNA
5.
Emerg Infect Dis ; 13(5): 687-93, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17553245

RESUMO

Domestic fleas were collected in 12 villages in the western Usambara Mountains in Tanzania. Of these, 7 are considered villages with high plague frequency, where human plague was recorded during at least 6 of the 17 plague seasons between 1986 and 2004. In the remaining 5 villages with low plague frequency, plague was either rare or unrecorded. Pulex irritans, known as the human flea, was the predominant flea species (72.4%) in houses. The density of P. irritans, but not of other domestic fleas, was significantly higher in villages with a higher plague frequency or incidence. Moreover, the P. irritans index was strongly positively correlated with plague frequency and with the logarithmically transformed plague incidence. These observations suggest that in Lushoto District human fleas may play a role in plague epidemiology. These findings are of immediate public health relevance because they provide an indicator that can be surveyed to assess the risk for plague.


Assuntos
Doenças Endêmicas , Insetos Vetores/classificação , Peste/epidemiologia , Sifonápteros/classificação , Topografia Médica/métodos , Animais , Estudos de Casos e Controles , Clima , Materiais de Construção/parasitologia , Coleta de Dados , Habitação , Humanos , Controle de Insetos/métodos , Insetos Vetores/microbiologia , Sifonápteros/microbiologia , Tanzânia/epidemiologia
6.
Mol Ecol ; 14(4): 1151-62, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15773942

RESUMO

We used mitochondrial cyt b sequences to investigate the phylogenetic relationships of Crocidura russula (sensu lato) populations across the Strait of Gibraltar, western Europe, Maghreb, and the Mediterranean and Atlantic islands. This revealed very low genetic divergence between European and Moroccan populations. The application of a molecular clock previously calibrated for shrews suggested that the separation of European from Moroccan lineages occurred less than 60 000 bp, which is at least 5 million years (Myr) after the reopening of the Strait of Gibraltar. This means that an overwater dispersal event was responsible for the observed phylogeographical structure. In contrast, genetic analyses revealed that Moroccan populations were highly distinct from Tunisian ones. According to the molecular clock, these populations separated about 2.2 million years ago (Ma), a time marked by sharp alternations of dry and humid climates in the Maghreb. The populations of the Mediterranean islands Ibiza, Pantelleria, and Sardinia were founded from Tunisian populations by overwater dispersal. In conclusion, overwater dispersal across the Strait of Gibraltar, probably assisted by humans, is possible for small terrestrial vertebrates. Moreover, as in Europe, Quaternary climatic fluctuations had a major effect on the phylogeographical structure of the Maghreb biota.


Assuntos
Clima , Variação Genética , Musaranhos/genética , Animais , Citocromos b/genética , Europa (Continente) , Geografia , Haplótipos , Mar Mediterrâneo , Marrocos , Filogenia , Alinhamento de Sequência , Análise de Sequência de DNA , Tunísia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA