Diversity, distribution and conservation of land mammals in Mauritania, North-West Africa.

Detailed knowledge about biodiversity distribution is critical for monitoring the biological effects of global change processes. Biodiversity knowledge gaps hamper the monitoring of conservation trends and they are especially evident in the desert biome. Mauritania constitutes a remarkable example on how remoteness and regional insecurity affect current knowledge gaps. Mammals remain one of the least studied groups in this country, without a concerted species checklist, the mapping of regions concentrating mammal diversity, or a national assessment of their conservation status. This work assessed the diversity, distribution, and conservation of land mammals in Mauritania. A total of 6,718 published and original observations were assembled in a spatial database and used to update the occurrence status, distribution area, and conservation status. The updated taxonomic list comprises 107 species, including 93 extant, 12 Regionally Extinct, and 2 Extinct in the Wild. Mapping of species distributions allowed locating concentrations of extant mammal species richness in coastal areas, along the Senegal River valley, and in mountain plateaus. Recent regional extinction of large-sized Artiodactyla and Carnivora has been very high (11% extinct species). From the extant mammals, 11% are threatened, including flagship species (e.g., Addax nasomaculatus and Panthera pardus). Species richness is poorly represented by the current protected areas. Despite the strong advances made, 23% of species categorise as Data Deficient. Persisting systematics and distribution uncertainties require further research. Field surveys in currently unexplored areas (northern and south-eastern regions) are urgently needed to increase knowledge about threatened mammals. The long-term conservation of land mammals in Mauritania is embedded in a complex web of socioeconomic and environmental factors that call for collaborative action and investment in sustainable human development. The current work sets the baseline for the future development of detailed research studies and to address the general challenges faced by mammals and biodiversity in the country.

Should I stay or should I go? Dispersal and population structure in small, isolated desert populations of West African crocodiles.

The maintenance of both spatial and genetic connectivity is paramount to the long-term persistence of small, isolated populations living in environments with extreme climates. We aim to identify the distribution of genetic diversity and assess population sub-structuring and dispersal across dwarfed desert populations of Crocodylus suchus, which occur in isolated groups, usually less than five individuals, along the mountains of Mauritania (West Africa). We used both invasive and non-invasive sampling methods and a combination of mitochondrial DNA (12 S and ND4) and microsatellite markers (32 loci and a subset of 12 loci). Our results showed high genetic differentiation and geographic structure in Mauritanian populations of C. suchus. We identified a metapopulation system acting within four river sub-basins (high gene flow and absence of genetic structure) and considerable genetic differentiation between sub-basins (FST range: 0.12-0.24) with rare dispersal events. Effective population sizes tend to be low within sub-basins while genetic diversity is maintained. Our study suggests that hydrographic networks (temporal connections along seasonal rivers during rainy periods) allow C. suchus to disperse and maintain metapopulation dynamics within sub-basins, which attenuate the loss of genetic diversity and the risk of extinction. We highlight the need of hydrographic conservation to protect vulnerable crocodiles isolated in small water bodies. We propose C. suchus as an umbrella species in Mauritania based on ecological affinities shared with other water-dependent species in desert environments.

Large spatial scale of the phenotype-environment color matching in two cryptic species of african desert jerboas (dipodidae: jaculus).

We tested the camouflage hypothesis, or the linkage between animal (Saharan rodent) and habitat coloration, on the largest geographical scale yet conducted. We aimed to determine whether phenotypic variation is explained by micro-habitat variation and/or genetic polymorphism to determine 1) the strength of linkage between fur color and local substrate color, and 2) the divergence in fur coloration between two genetic clades, representing cryptic species, throughout the complete range of the African desert jerboas (Jaculus jaculus). We used a combination of museum and field-collected specimens, remote sensing tools, satellite and digital photography and molecular genetic and phylogenetic methods to investigate the above hypotheses. Along with showing that the two divergent genetic clades of jerboas occur sympatrically throughout their African distribution, we showed significant covariation between dorsal fur coloration of the animals and the color of their habitat. We also described significant phenotypic divergence in fur color, consistent with genetic divergence between the sympatric clades. The linkage between environment and phenotype supports the idea that the selection promoting cryptic coloration is persistent in contemporary populations of jerboas, however the phenotypic divergence indicates that it has different strengths (or optima) in the two clades. The mosaic distribution of micro-habitats occupied by geographically sympatric clades suggests that it may influence both ecological and evolutionary dynamics between these two cryptic species.

Intracranial meningiomas in children: ten-year experience.

Meningiomas are central nervous system neoplasms derived from arachnoid cap cells. They are the second most common brain tumors after gliomas, but are rare in children. Furthermore, meningiomas exhibit different behavior in this age group. From 1997-2007, 7 children with brain meningiomas were treated at the Department of Neurosurgery, Brazilian National Cancer Institute, Rio de Janeiro, Brazil. They represented 2.7% of all brain meningiomas, and 2.1% of all brain tumors, in children followed during this period at our institution. There were 4 boys, and the mean age at diagnosis was 7.3 years. Headaches, seizures, and motor deficits were the most frequent signs at presentation. All patients underwent surgery, and total resection was achieved in 6 of 7 patients. Most lesions were World Health Organization class I meningiomas. There were no deaths, and patients were asymptomatic or demonstrated mild motor or sensory signs at follow-up. In conclusion, meningiomas are rare in the pediatric population. Most of the lesions are low-grade, and the prognosis in this setting is good.

Bilateral ptosis and supranuclear downgaze paralysis.

The purpose of this article is to highlight an uncommon combination of supranuclear downward gaze paralysis with bilateral eyelid ptosis in a 53-year-old man with a radiation induced midbrain tumor and to discuss the aspects regarding the centers and pathways that mediate supranuclear vertical gaze movements.

Bilateral ptosis and supranuclear downgaze paralysis

The purpose of this article is to highlight an uncommon combination of supranuclear downward gaze paralysis with bilateral eyelid ptosis in a 53-years-old man with a radiation induced midbrain tumor and to discuss the aspects regarding the centers and pathways that mediate supranuclear vertical gaze movements.

O objetivo deste artigo é ressaltar uma rara condição caracterizada por paralisia supranuclear do olhar conjugado para baixo associada a ptose palpebral bilateral em um homem de 53 anos, causada por tumor mesencefálico radio-induzido, e discutir os aspectos relacionados ao controle supranuclear dos movimentos oculares verticais.

Obstruçäo intestinal: caso incomun por membrana congênita de duodeno / Intestinal obstruction: unusual case by duodenal congenital WEB

Os autores descrevem um caso incomum de obstruçäo intestinal, causada por uma membrana congênita na terceira porçäo do arco duodenal, analisam de forma sucinta a literatura e discutem os métodos diagnósticos assim, como o tratamento. Paciente de 26 anos de idade, casada caucasiana, coucasiana, com história de dispepsia gástrica e plenitude-prandial há 20 anos, com quadro de obstruçäo intestinal há 3, foi internada e submetida a exames subsidiários. Os exames radiológicos e endoscópico evidenciaram restos alimentares no estômago e duodeno, divertículo na terceira porçäo do arco duodenal e megabulbo. Foi indicada cirurgia de urgência onde encontrou-se o estômago e o duodeno como causa mecânica da obstruçäo, com pequeno pertuito central de 4 a 5 mm de diâmetro associado a úlcera adjacente e litíase biliar. Foi realizada gastrectomia à Biltroth II e colecistectomia sendo que aproximadamente em 40 dias de pós-operatório a paciente já se alimentava normalmente sem apresentar nenhum sintomatologia. Atualmente, 2 anos e 8 meses após a cirurgia, a paciente alimenta-se sem restriçöes, näo apresenta nenhum sintoma de moléstia gastrointestinal e suas funçöes fisiológicas säo normais