Exploring the main threats to the threatened African spurred tortoise Centrochelys sulcata in the West African Sahel

AbstractThe African spurred tortoiseCentrochelys sulcatais the second largest terrestrial turtle, with a scattered distribution across the West African Sahel. This species is threatened and declining consistently throughout its range, but little is known about the causes of its decline. It has been hypothesized that the decline is attributable to (1) competition with domestic cattle, (2) wildfire, and (3) the international pet trade. We conducted a series of analyses to investigate these three causes. Hypotheses 1 and 2 were analysed using a spatially explicit approach, using a database of the Food and Agriculture Organization of the United Nations and logistic regression modelling; hypothesis 3 was tested by analysing the CITES trade database for 1990–2010. We found a significant negative correlation between intensity of grazing (expressed as density of cattle, km−2) and the presence of spurred tortoises, and this negative effect increased when coupled with high fire intensity, whereas wildfires alone did not have a significant influence on the species' distribution at the global scale. There was a decrease in the annual export of wild individuals for the pet trade after the introduction of export quotas by country and by year, but trade data must be considered with caution

Global patterns of body size evolution in squamate reptiles are not driven by climate

Aim: Variation in body size across animal species underlies most ecological and evolutionary processes shaping local- and large-scale patterns of biodiversity. For well over a century, climatic factors have been regarded as primary sources of natural selection on animal body size, and hypotheses such as Bergmann's rule (the increase of body size with decreasing temperature) have dominated discussions. However, evidence for consistent climatic effects, especially among ectotherms, remains equivocal. Here, we test a range of key hypotheses on climate-driven size evolution in squamate reptiles across several spatial and phylogenetic scales. Location: Global. Time period: Extant. Major taxa studied: Squamates (lizards and snakes). Methods: We quantified the role of temperature, precipitation, seasonality and net primary productivity as drivers of body mass across ca. 95% of extant squamate species (9,733 spp.). We ran spatial autoregressive models of phylogenetically corrected median mass per equal-area grid cell. We ran models globally, across separate continents and for major squamate clades independently. We also performed species-level analyses using phylogenetic generalized least square models and linear regressions of independent contrasts of sister species. Results: Our analyses failed to identify consistent spatial patterns in body size as a function of our climatic predictors. Nearly all continent- and family-level models differed from one another, and species-level models had low explanatory power. Main conclusions: The global distribution of body mass among living squamates varies independently from the variation in multiple components of climate. Our study, the largest in spatial and taxonomic scale conducted to date, reveals that there is little support for a universal, consistent mechanism of climate-driven size evolution within squamates

Integration of nuclear and mitochondrial gene sequences and morphology reveals unexpected diversity in the forest cobra (Naja melanoleuca) species complex in Central and West Africa (Serpentes: Elapidae)

Cobras are among the most widely known venomous snakes, and yet their taxonomy remains incompletely understood, particularly in Africa. Here, we use a combination of mitochondrial and nuclear gene sequences and morphological data to diagnose species limits within the African forest cobra, Naja (Boulengerina) melanoleuca. Mitochondrial DNA sequences reveal deep divergences within this taxon. Congruent patterns of variation in mtDNA, nuclear genes and morphology support the recognition of five separate species, confirming the species status of N. subfulva and N. peroescobari, and revealing two previously unnamed West African species, which are described as new: Naja (Boulengerina) guineensis sp. nov. Broadley, Trape, Chirio, Ineich and Wüster, from the Upper Guinea forest of West Africa, and Naja (Boulengerina) savannula sp. nov. Broadley, Trape, Chirio and Wüster, a banded form from the savanna-forest mosaic of the Guinea and Sudanian savannas of West Africa. The discovery of cryptic diversity in this iconic group highlights our limited understanding of tropical African biodiversity, hindering our ability to conserve it effectivel

The global biogeography of lizard functional groups

Aim: Understanding the mechanisms determining species richness is a primary goal of biogeography. Richness patterns of sub-groups within a taxon are usually assumed to be driven by similar processes. However, if richness of distinct ecological strategies respond differently to the same processes, inferences made for an entire taxon may be misleading. We deconstruct the global lizard assemblage into functional groups and examine the congruence among richness patterns between them. We further examine the species richness – functional richness relationship to elucidate the way functional diversity contributes to the overall species richness patterns. Location: Global. Methods: Using comprehensive biological trait databases we classified the global lizard assemblage into ecological strategies based on body size, diet, activity times and microhabitat preferences, using Archetypal Analysis. We then examined spatial gradients in the richness of each strategy at the one-degree grid cell, biomes and realm scales. Results: We found that lizards can best be characterized by seven 'ecological strategies': scansorial, terrestrial, nocturnal, herbivorous, fossorial, large and semiaquatic. There are large differences among the global richness patterns of these strategies. While the major richness hotspot for lizards in general is in Australia, several strategies exhibit highest richness in the Amazon Basin. Importantly, the global maximum in lizard species richness is achieved at intermediate values of functional diversity and increasing functional diversity further result in a shallow decline of species richness. Main conclusions: The deconstruction of the global lizard assemblage along multiple ecological axes offers a new way to conceive lizard diversity patterns. It suggests that local lizard richness mostly increases when species belonging to particular ecological strategies become hyper-diverse there, and not because more ecological types are present in the most species rich localities. Thus maximum richness and maximum ecological diversity do not overlap. These results shed light on the global richness pattern of lizards, and highlight previously unidentified spatial patterns in understudied functional groups

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

Telecardiogram: Still of matter in the modern cardiac imaging era?

The modern cardiovascular imaging era has seen the introduction in clinical practice of highly innovative and performing diagnostic features. The negative side of this outstanding evolution risks to be an underassessment of well-established classical diagnostic techniques. Thereby, to support the actual relevance of a properly executed chest X-ray, this article describes two paradigmatic cases of exceptional cardiac abnormalities, in which X-rays played a key diagnostic role

Data from: Ecophysiological variation across a forest-ecotone gradient produces divergent climate change vulnerability within species

Climate change related risks and impacts on ectotherms will be mediated by habitats and their influence on local thermal environments. While many studies have documented morphological and genetic aspects of niche divergence across habitats, few have examined thermal performance across such gradients and directly linked this variation to contemporary climate change impacts. In this study, we quantified variation in thermal performance across a gradient from forest to gallery forest-savanna mosaic in Cameroon for a skink species (Trachylepis affinis) known to be diverging genetically and morphologically across that habitat gradient. Based on these results, we then applied a mechanistic modelling approach (NicheMapR) to project changes in potential activity, as constrained by thermal performance, in response to climate change. As a complimentary approach, we also compared mechanistic projections with climate-driven changes in habitat suitability based on species distribution models of forest and ecotone skinks. We found that ecotone skinks may benefit from warming and experience increased activity while forest skinks will likely face a drastic decrease in thermal suitability across the forest zone. Species distribution models projected that thermal suitability for forest skinks in coastal forests would decline but in other parts of the forest zone skinks are projected to experience increased thermal suitability. The results here highlight the utility of mechanistic approaches in revealing and understanding patterns of climate change vulnerability which may not be detected with species distribution models alone. This study also emphasizes the importance of intra-specific physiological variation, and habitat-specific thermal performance relationships in particular, in determining warming responses