Origins of Biodiversity

Biodiversity today is huge, and it has a long history. Identifying rules for the heterogeneity of modern biodiversity-the high to low species richness of different clades-has been hard. There are measurable biodiversity differences between land and sea and between the tropics and temperate-polar regions. Some analyses suggest that the net age of a clade can determine its extinction risk, but this is equivocal. New work shows that, through geological time, clades pass through different diversification regimes, and those regimes constrain the balance of tree size and the nature of branching events

Sea surface temperature contributes to marine crocodylomorph evolution

During the Mesozoic and Cenozoic, four distinct crocodylomorph lineages colonized the marine environment. They were conspicuously absent from high latitudes, which in the Mesozoic were occupied by warm-blooded ichthyosaurs and plesiosaurs. Despite a relatively well-constrained stratigraphic distribution, the varying diversities of marine crocodylomorphs are poorly understood, because their extinctions neither coincided with any major biological crises nor with the advent of potential competitors. Here we test the potential link between their evolutionary history in terms of taxic diversity and two abiotic factors, sea level variations and sea surface temperatures (SST). Excluding Metriorhynchoidea, which may have had a peculiar ecology, significant correlations obtained between generic diversity and estimated Tethyan SST suggest that water temperature was a driver of marine crocodylomorph diversity. Being most probably ectothermic reptiles, these lineages colonized the marine realm and diversified during warm periods, then declined or became extinct during cold intervals

Effect of Vapocoolant on Pain During Peripheral Intravenous Cannulation

Methods Data Sources The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Literatura Latino Americana em Ciencias da Saude, Cumulative Index to Nursing and Allied Health Literature, and ISI Web of Science were searched from inception to May 2015 without language restriction. Trial registries were searched, including clinicaltrials.gov, controlled-trials.com, and trialscentral.org. Additionally, the authors hand searched the references of retrieved articles and abstracts of the American Society of Anesthesiologists. Study Selection This review included all randomized controlled trials comparing vapocoolant to placebo or no treatment for analgesia associated with intravenous cannulation. Studies of adults, children, and healthy volunteers were eligible. Titles and abstracts were reviewed by at least 2 authors, and potentially relevant studies underwent full text review. Discrepancies in study selection were resolved by consensus. Data Extraction and Synthesis Three authors independently extracted data, using a standardized data extraction form. Discrepancies in extracted data were resolved by consensus. Studies were assessed as low, unclear, or high risk of bias in each of 6 domains: random sequence generation, allocation concealment, blinding of participants and personnel, blinding of outcome assessors, incomplete outcome data, and selective reporting. Data reported on a 100-point visual analog scale (VAS) were reported as mean difference. When data were measured with different scales, they were combined with standardized mean difference. A fixed-effect model was used when the I2 statistic was less than 40%; otherwise, a random-effects model was used

Obituary: Arthur Cruickshank 1932 - 2011. A native Gondwanan, who studied the former continent's fossil tetrapods

Dr Arthur Richard Ivor Cruickshank died on 4th December 2011, aged 79, in the Borders General Hospital, Melrose, Scotland. Arthur Cruickshank was part of the post-war generation of palaeontologists who laid the foundations on which today’s researchers build. Appropriately for someone from an expatriate Scots family living in Kenya, much of his work was on the extinct reptiles of the great southern palaeocontinent of Gondwana

The fossil record of early tetrapods: worker effort and the end-Permian mass extinction

It is important to understand the quality of the fossil record of early tetrapods (Tetrapoda, minus Lissamphibia and Amniota) because of their key role in the transition of vertebrates from water to land, their dominance of terrestrial faunas for over 100 million years of the late Palaeozoic and earlyMesozoic, and their variable fates during the end−Permian mass extinction. The first description of an early tetrapod dates back to 1824, and since then discoveries have occurred at a rather irregular pace, with peaks and troughs corresponding to some of the vicissitudes of human history through the past two centuries. As expected, the record is dominated by the well−sampled sedimentary basins of Europe and North America, but finds from other continents are increasing rapidly. Comparisons of snapshots of knowledge in 1900, 1950, and 2000 show that discovery of new species has changed the shape of the species−level diversification curve, contrary to earlier studies of family−level taxa. There is, however, little evidence that taxon counts relate to research effort (as counted by numbers of publications), and there are no biasing effects associated with differential study of different time intervals through the late Palaeozoic and Mesozoic. In fact, levels of effort are apparently not related to geological time, with no evidence that workers have spent more time on more recent parts of the record. In particular, the end−Permian mass extinction was investigated to determine whether diversity changes through that interval might reflect worker effort: it turns out that most records of early tetrapod taxa (when corrected for duration of geological series) occur in the Lower Triassic