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Author

William R. Branch

Other affiliations: University of the Witwatersrand
Bio: William R. Branch is an academic researcher from Nelson Mandela Metropolitan University. The author has contributed to research in topics: Monophyly & Sexual dimorphism. The author has an hindex of 30, co-authored 123 publications receiving 3906 citations. Previous affiliations of William R. Branch include University of the Witwatersrand.


Papers
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Journal ArticleDOI
14 May 2010-Science
TL;DR: Global extinction projections were validated with local extinctions observed from 1975 to 2009 for regional biotas on four other continents, suggesting that lizards have already crossed a threshold for extinctions caused by climate change.
Abstract: It is predicted that climate change will cause species extinctions and distributional shifts in coming decades, but data to validate these predictions are relatively scarce Here, we compare recent and historical surveys for 48 Mexican lizard species at 200 sites Since 1975, 12% of local populations have gone extinct We verified physiological models of extinction risk with observed local extinctions and extended projections worldwide Since 1975, we estimate that 4% of local populations have gone extinct worldwide, but by 2080 local extinctions are projected to reach 39% worldwide, and species extinctions may reach 20% Global extinction projections were validated with local extinctions observed from 1975 to 2009 for regional biotas on four other continents, suggesting that lizards have already crossed a threshold for extinctions caused by climate change

1,483 citations

Journal ArticleDOI
01 Oct 2009-Zootaxa
TL;DR: DNA sequence analyses of 91 individuals representing 34 recognized species of leptotyphlopids show divergences among living lineages as early as the mid-Cretaceous, and evidence that the breakup of West Gondwana into South America and Africa and the separation of West Africa from South and East Africa by high sea levels in the Cretaceous influenced the biogeographic history of the family through isolation.
Abstract: The family Leptotyphlopidae (116 species) includes the smallest and thinnest species of snakes, often called threadsnakes (or wormsnakes). They are burrowing, have small eyes, and they feed on several life history stages of social insects. Leptotyphlopids have a West Gondwanan distribution, occurring primarily in Africa and the Neotropics (South America, Middle America, and the West Indies). The family is one of the most poorly known of all terrestrial vertebrates from the standpoint of systematics and ecology. No published phylogenetic studies of higher-level relationships exist, either from morphological or molecular data. Here we present DNA sequence analyses of 91 individuals representing 34 recognized species of leptotyphlopids, from nine mitochondrial and nuclear genes. The results show divergences among living lineages as early as the mid-Cretaceous, 92 (113–75) million years ago (Ma) and evidence that the breakup of West Gondwana into South America and Africa, and the separation of West Africa from South and East Africa by high sea levels in the Cretaceous, influenced the biogeographic history of the family through isolation. A Late Cretaceous (78 Ma; 98–63 Ma) transatlantic dispersal from West Africa to South America may explain the origin of the monophyletic New World radiation. Mid-Cenozoic divergences among Middle and North American species indicate that leptotyphlopids dispersed to those regions from South America, by rafting over water, prior to the emergence of the Isthmus of Panama. A revised classification recognizes two subfamilies, Epictinae subfam. nov. (New World and Africa) and Leptotyphlopinae (Africa, Arabia, and Southwest Asia). Within the Epictinae we recognize two tribes (Epictini trib. nov. and Rhinoleptini trib. nov.), three subtribes (Epictina subtrib. nov., Tetracheilostomina subtrib. nov., and Renina subtrib. nov.), and eight genera (Epictia, Guinea gen. nov., Mitophis gen. nov., Rena, Rhinoleptus, Siagonodon, Tetracheilostoma, and Tricheilostoma). Three tribes are recognized within the Leptotyphlopinae (Epacrophini trib. nov., Myriopholini trib. nov., and Leptotyphlopini trib. nov.) and four genera (Epacrophis gen. nov., Myriopholis gen. nov., Leptotyphlops, and Namibiana gen. nov.). The significant non-monophyly of some species and the estimated long period of time (tens of millions of years) separating populations of currently recognized species indicate that an unusually large number of species exist that are unrecognized. This combined with small distributions and high levels of deforestation in these areas argue for increased awareness of leptotyphlopids and other burrowing reptiles in conservation planning.

122 citations

Journal ArticleDOI
TL;DR: It is found that the earliest blindsnake lineages, representing two new families described here, were distributed on the palaeolandmass of India+Madagascar named here as Indigascar, and their later evolution out of IndIGascar involved vicariance and several oceanic dispersal events, including a westward transatlantic one, unexpected for burrowing animals.
Abstract: Worm-like snakes (scolecophidians) are small, burrowing species with reduced vision. Although largely neglected in vertebrate research, knowledge of their biogeographical history is crucial for evaluating hypotheses of snake origins. We constructed a molecular dataset for scolecophidians with detailed sampling within the largest family, Typhlopidae (blindsnakes). Our results demonstrate that scolecophidians have had a long Gondwanan history, and that their initial diversification followed a vicariant event: the separation of East and West Gondwana approximately 150 Ma. We find that the earliest blindsnake lineages, representing two new families described here, were distributed on the palaeolandmass of India+Madagascar named here as Indigascar. Their later evolution out of Indigascar involved vicariance and several oceanic dispersal events, including a westward transatlantic one, unexpected for burrowing animals. The exceptional diversification of scolecophidians in the Cenozoic was probably linked to a parallel radiation of prey (ants and termites) as well as increased isolation of populations facilitated by their fossorial habits.

110 citations

Journal ArticleDOI
TL;DR: These alternative hypotheses using data for a diverse genus of East African forest chameleons, Kinyongia, showed that accumulation of new species due to radiation within refugial habitats or retention of older palaeoendemic species in stable refugia is possible.
Abstract: Aim East Africa is one of the most biologically diverse regions, especially in terms of endemism and species richness. Hypotheses put forward to explain this high diversity invoke a role for forest refugia through: (1) accumulation of new species due to radiation within refugial habitats, or (2) retention of older palaeoendemic species in stable refugia. We tested these alternative hypotheses using data for a diverse genus of East African forest chameleons, Kinyongia. Location East Africa. Methods We constructed a dated phylogeny for Kinyongia using one nuclear and two mitochondrial markers. We identified areas of high phylogenetic diversity (PD) and evolutionary diversity (ED), and mapped ancestral areas to ascertain whether lineage diversification could best be explained by vicariance or dispersal. Results Vicariance best explains the present biogeographic patterns, with divergence between three major Kinyongia clades (Albertine Rift, southern Eastern Arc, northern Eastern Arc) in the early Miocene/Oligocene (> 20 Ma). Lineage diversification within these clades pre-dates the Pliocene (> 6 Ma). These dates are much older than the Plio-Pleistocene climatic shifts associated with cladogenesis in other East African taxa (e.g. birds), and instead point to a scenario whereby palaeoendemics are retained in refugia, rather than more recent radiations within refugia. Estimates of PD show that diversity was highest in the Uluguru, Nguru and East Usambara Mountains and several lineages (from Mount Kenya, South Pare and the Uluguru Mountains) stand out as being evolutionarily distinct as a result of isolation in forest refugia. PD was lower than expected by chance, suggesting that the phylogenetic signal is influenced by an unusually low number of extant lineages with long branch lengths, which is probably due to the retention of palaeoendemic lineages. Main conclusions The biogeographic patterns associated with Kinyongia are the result of long evolutionary histories in isolation. The phylogeny is dominated by ancient lineages whose origins date back to the early Miocene/Oligocene as a result of continental wide forest fragmentation and contraction due to long term climatic changes in Africa. The maintenance of palaeoendemic lineages in refugia has contributed substantially to the remarkably high biodiversity of East Africa.

99 citations

Journal ArticleDOI
TL;DR: This taxonomic reassessment divides the family into 10 genera, corresponding to these well-supported, monophyletic lineages, and shows short internodes and low support between the non-platysaur lineages are consistent with a rapid radiation event at the base of the viviparous cordylids.

87 citations


Cited by
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28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

Journal ArticleDOI
19 Aug 2011-Science
TL;DR: A meta-analysis shows that species are shifting their distributions in response to climate change at an accelerating rate, and that the range shift of each species depends on multiple internal species traits and external drivers of change.
Abstract: The distributions of many terrestrial organisms are currently shifting in latitude or elevation in response to changing climate Using a meta-analysis, we estimated that the distributions of species have recently shifted to higher elevations at a median rate of 110 meters per decade, and to higher latitudes at a median rate of 169 kilometers per decade These rates are approximately two and three times faster than previously reported The distances moved by species are greatest in studies showing the highest levels of warming, with average latitudinal shifts being generally sufficient to track temperature changes However, individual species vary greatly in their rates of change, suggesting that the range shift of each species depends on multiple internal species traits and external drivers of change Rapid average shifts derive from a wide diversity of responses by individual species

3,986 citations

Journal ArticleDOI
03 Mar 2011-Nature
TL;DR: Differences between fossil and modern data and the addition of recently available palaeontological information influence understanding of the current extinction crisis, and results confirm that current extinction rates are higher than would be expected from the fossil record.
Abstract: Palaeontologists characterize mass extinctions as times when the Earth loses more than three-quarters of its species in a geologically short interval, as has happened only five times in the past 540 million years or so. Biologists now suggest that a sixth mass extinction may be under way, given the known species losses over the past few centuries and millennia. Here we review how differences between fossil and modern data and the addition of recently available palaeontological information influence our understanding of the current extinction crisis. Our results confirm that current extinction rates are higher than would be expected from the fossil record, highlighting the need for effective conservation measures.

3,051 citations

Journal ArticleDOI
TL;DR: Overall, this review shows that current estimates of future biodiversity are very variable, depending on the method, taxonomic group, biodiversity loss metrics, spatial scales and time periods considered.
Abstract: Many studies in recent years have investigated the effects of climate change on the future of biodiversity. In this review, we first examine the different possible effects of climate change that can operate at individual, population, species, community, ecosystem and biome scales, notably showing that species can respond to climate change challenges by shifting their climatic niche along three non-exclusive axes: time (e.g. phenology), space (e.g. range) and self (e.g. physiology). Then, we present the principal specificities and caveats of the most common approaches used to estimate future biodiversity at global and sub-continental scales and we synthesise their results. Finally, we highlight several challenges for future research both in theoretical and applied realms. Overall, our review shows that current estimates are very variable, depending on the method, taxonomic group, biodiversity loss metrics, spatial scales and time periods considered. Yet, the majority of models indicate alarming consequences for biodiversity, with the worst-case scenarios leading to extinction rates that would qualify as the sixth mass extinction in the history of the earth.

2,834 citations