64 research outputs found
Diversity, elevational variation, and phylogeographic origin of stump-toed frogs (Microhylidae: Cophylinae: Stumpffia) on the Marojejy massif, northern Madagascar
Stump-toed frogs (genus Stumpffia Boettger, 1881) are a diverse group of small-bodied frogs endemic to Madagascar. Seven species of this genus occur on Marojejy, a steep massif in northeastern Madagascar. Here we examine the elevational distribution, phylogenetic position, biogeographic origin, and genetic differentiation of this Stumpffia assemblage. We show that none of these species is another’s closest relative, but rather they are all independent lineages that probably colonised the Marojejy Massif through repeated immigration events. All of the lineages on Marojejy are most closely related to species south and southwest of the massif, except one lineage, formerly known as Stumpffia sp. Ca07, but here assigned to S. sorata as a deep conspecific lineage (and referred to as S. cf. sorata), which occurs also in Sorata, 90 km north of Marojejy. The species on Marojejy are typically restricted to narrow elevational ranges, but at least two species, S. cf. sorata and S. tridactyla, occur over elevations spanning 1000 metres. We assessed the genetic variability of these populations, and found considerable haplotype separation in fragments of the mitochondrial 16S rRNA and nuclear Rag-1 genes, suggesting some disruption of gene flow associated with elevation. We discuss the biogeographic implications of our findings and, based on previously published data, the evolution of non-overlapping bioacoustic parameters among the diverse assemblage of Stumpffia species on the Marojejy massif
Morphological and ecological convergence at the lower size limit for vertebrates highlighted by five new miniaturised microhylid frog species from three different Madagascan genera
Miniaturised frogs form a fascinating but poorly understood amphibian ecomorph and have been exceptionally prone to taxonomic underestimation. The subfamily Cophylinae (family Microhylidae), endemic to Madagascar, has a particularly large diversity of miniaturised species which have historically been attributed to the single genus Stumpffia largely based on their small size. Recent phylogenetic work has revealed that several independent lineages of cophyline microhylids evolved towards highly miniaturised body sizes, achieving adult snout- vent lengths under 16 mm. Here, we describe five new species belonging to three clades that independently miniaturised and that are all genetically highly divergent from their relatives: (i) a new genus (Mini gen.nov.) with three new species from southern Madagascar, (ii) one species of Rhombophryne, and (iii) one species of Anodonthyla. Mini mum sp. nov. from Manombo in eastern Madagascar is one of the smallest frogs in the world, reaching an adult body size of 9.7 mm in males and 11.3 mm in females. Mini scule sp.nov. from Sainte Luce in southeastern Madagascar is slightly larger and has maxillary teeth. Mini ature sp.nov. from Andohahela in southeast Madagascar is larger than its congeners but is similar in build. Rhombophryne proportionalis sp.nov. from Tsaratanana in northern Madagascar is unique among Madagascar's miniaturised frogs in being a proportional dwarf, exhibiting far less advanced signs of paedomorphism than other species of similar size. Anodonthyla eximia sp.nov. from Ranomafana in eastern Madagascar is distinctly smaller than any of its congeners and is secondarily terrestrial, providing evidence that miniaturisation and terrestriality may be evolutionarily linked. The evolution of body size in Madagascar's microhylids has been more dynamic than previously understood, and future studies will hopefully shed light on the interplay between ecology and evolution of these remarkably diverse frogs
Geography-dependent horizontal gene transfer from vertebrate predators to their prey
Horizontal transfer (HT) of genes between multicellular animals, once thought to be extremely rare, is being more commonly detected, but its global geographic trend and transfer mechanism have not been investigated. We discovered a unique HT pattern of Bovine-B (BovB) LINE retrotransposons in vertebrates, with a bizarre transfer direction from predators (snakes) to their prey (frogs). At least 54 instances of BovB HT were detected, which we estimate to have occurred across time between 85 and 1.3 Ma. Using comprehensive transcontinental sampling, our study demonstrates that BovB HT is highly prevalent in one geographical region, Madagascar, suggesting important regional differences in the occurrence of HTs. We discovered parasite vectors that may plausibly transmit BovB and found that the proportion of BovB-positive parasites is also high in Madagascar where BovB thus might be physically transported by parasites to diverse vertebrates, potentially including humans. Remarkably, in two frog lineages, BovB HT occurred after migration from a non-HT area (Africa) to the HT hotspot (Madagascar). These results provide a novel perspective on how the prevalence of parasites influences the occurrence of HT in a region, similar to pathogens and their vectors in some endemic diseases
Smallholder Zebu and Forage Production Development in Central Madagascar
Poverty in the Central Highlands of Madagascar is partly driven by inefficient exploitation of native forages and poor livestock nutrition. Zebus are of importance as cultural symbols, but this tradition has grown disconnected from agricultural policy. This project is working with three central highland communities near the protected areas of Itremo, Ibity and Ankafobe, to boost rangeland productivity and trial management methods which will support key forage grasses and improve livestock nutrition. A severe nitrogen deficiency compounded by extremely acidic soil conditions and low phosphorus is observed across the three sites. The lowest grazing capacity of an estimated 0.7 livestock unit per hectare and biomass production of 1600 kg/ha is observed at Ankafobe, the highest elevation windy site with fires that are almost annual. Low production is due to acidic soils with a lack of phosphorus as well as likely iron toxicity. The project works with 90 households owning a total 150 female zebu, 1-5 per household. The project initiated 3 demonstration farms to show the planting of sorghum for silage, harvesting of the native grasses for hay, and building a secure barn meeting at least minimum animal care standards, using local materials to protect the livestock from the weather and theft which is sadly perceived to be common. In the first year the project produced the highest yields in the most remote and fertile site of Itremo, with 365 kg of sorghum silage from 0.5 ha and 165 kg of Brachiaria hay from 0.5 ha. Five households based in the milk producing region of eastern Ibity have completed new barns. Fifty percent of households at Ibity successfully fed silage and hay to their zebu for the first time. Madagascar remains famous for subsistence farming and rural poverty with a long-term decline in livestock, but substantial opportunity nevertheless exists for integrated crop and livestock production, alongside the protection of biodiversity in nearby forests
A distinctive new frog species (Anura, Mantellidae) supports the biogeographic linkage of two montane rainforest massifs in northern Madagascar
We describe a new species of the genus Gephyromantis, subgenus Vatomantis (Mantellidae, Mantellinae), from moderately high elevation (1164–1394 m a.s.l.) on the Marojejy, Sorata, and Andravory Massifs in northern Madagascar. The new species, Gephyromantis (Vatomantis) lomorina sp. n. is highly distinct from all other species, and was immediately recognisable as an undescribed taxon upon its discovery. It is characterised by a granular, mottled black and green skin, reddish eyes, paired subgular vocal sacs of partly white colour, bulbous femoral glands present only in males and consisting of three large granules, white ventral spotting, and a unique, amplitude-modulated advertisement call consisting of a series of 24–29 rapid, quiet notes at a dominant frequency of 5124–5512 Hz. Genetically the species is also strongly distinct from its congeners, with uncorrected pairwise distances ≥10 % in a fragment of the mitochondrial 16S rRNA gene to all other nominal Gephyromantis species. A molecular phylogeny based on 16S sequences places it in a clade with species of the subgenera Laurentomantis and Vatomantis, and we assign it to the latter subgenus based on its morphological resemblance to members of Vatomantis. We discuss the biogeography of reptiles and amphibians across the massifs of northern Madagascar, the evidence for a strong link between Marojejy and Sorata, and the role of elevation in determining community sharing across this landscape
Prioritizing Health-Sector Interventions for Noncommunicable Diseases and Injuries in Low- and Lower-Middle Income Countries: National NCDI Poverty Commissions
Health sector priorities and interventions to prevent and manage noncommunicable diseases and injuries (NCDIs) in low- and lower-middle-income countries (LLMICs) have primarily adopted elements of the World Health Organization Global Action Plan for NCDs 2013–2020. However, there have been limited efforts in LLMICs to prioritize among conditions and health-sector interventions for NCDIs based on local epidemiology and contextually relevant risk factors or that incorporate the equitable distribution of health outcomes. The Lancet Commission on Reframing Noncommunicable Diseases and Injuries for the Poorest Billion supported national NCDI Poverty Commissions to define local NCDI epidemiology, determine an expanded set of priority NCDI conditions, and recommend cost-effective, equitable health-sector interventions. Fifteen national commissions and 1 state-level commission were established from 2016–2019. Six commissions completed the prioritization exercise and selected an average of 25 NCDI conditions; 15 conditions were selected by all commissions, including asthma, breast cancer, cervical cancer, diabetes mellitus type 1 and 2, epilepsy, hypertensive heart disease, intracerebral hemorrhage, ischemic heart disease, ischemic stroke, major depressive disorder, motor vehicle road injuries, rheumatic heart disease, sickle cell disorders, and subarachnoid hemorrhage. The commissions prioritized an average of 35 health-sector interventions based on cost-effectiveness, financial risk protection, and equity-enhancing rankings. The prioritized interventions were estimated to cost an additional US13.70 per capita or approximately 9.7%–35.6% of current total health expenditure (0.6%–4.0% of current gross domestic product). Semistructured surveys and qualitative interviews of commission representatives demonstrated positive outcomes in several thematic areas, including understanding NCDIs of poverty, informing national planning and implementation of NCDI health-sector interventions, and improving governance and coordination for NCDIs. Overall, national NCDI Poverty Commissions provided a platform for evidence-based, locally driven determination of priorities within NCDIs.publishedVersio
Le projet de recherche Ecorisques : de quoi s'agit-il ?
National audienceLe projet Ecorisques a été piloté par le département Recherche, Développement et Innovation de l'ONF. Son intitulé complet est "Optimisation et viabilité de la gestion forestière en présence de risques". Optimisation et viabilité sont deux types de modélisation économique, qu'on se propose d'utiliser pour aider à la décision en matière de gestion forestière dans un contexte empreint d'aléas. Ambition énorme qu'on limite, dans ce projet exploratoire, aux incertitudes de prix et au risque tempête, en se focalisant sur deux cas d'étude
Biogéographie de Madagascar = Biogeography of Madagascar
Des données originelles sont présentées concernant la découverte d'une espèce de Lémurien pratiquement éteinte, #Allocebus trichotis$, dans une région de répartition préalablement inconnue dans des forêts humides des terres hautes à l'Est de Madagascar. Les conséquences et l'intérêt aussi bien pour la biogéographie que pour la conservation sont également discutés. (Résumé d'auteur
Using Coulombian Approach for Modeling Scalar Potential and Magnetic Field of a Permanent Magnet With Radial Polarization
New compact semianalytical expressions of the scalar potential and magnetic fields produced by a radially polarized permanent magnet are described in this paper by using Coulombian approach. It uses fictitious magnetic charge to model the magnetic field intensity. With this fast model, we can compute the demagnetization field in each point inside the permanent magnet and the magnetic fields outside it. Index Terms—Analytical model, magnetic field, radial polarized magnet. I
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