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Creators/Authors contains: "Azevedo, Guilherme H. F."

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  1. ; ; ; ; ; ( , Insect Systematics and Diversity)
    Abstract

    Traits that independently evolve many times are important for testing hypotheses about correlated evolution and understanding the forces shaping biodiversity. However, population genetics processes can cause hemiplasies (traits determined by genes whose topologies do not match the species tree), leading to a false impression of convergence (homoplasy) and potentially misleading inferences of correlated evolution. Discerning between homoplasies and hemiplasies can be important in cases of rapid radiations and clades with many gene tree incongruences. Here, focusing on two-clawed spiders (Dionycha) and close relatives, we evaluate if the observed distribution of characters related to a web-less lifestyle could be better explained as synapomorphies, homoplasies, or hemiplasies. We find that, although there are several convergences, hemiplasies are also sometimes probable. We discuss how these hemiplasies could affect inferences about correlation and causal relationship of traits. Understanding when and where in the tree of life hemiplasy could have happened is important, preventing false inference of convergent evolution. Furthermore, this understanding can provide alternative hypotheses that can be tested with independent data. Using traits related to the climbing ability of spiders we show that, when hemiplasy is unlikely, adequate model testing can be used to better understand correlated evolution, and propose hypotheses to be tested using controlled behavioral and mechanical experiments.

     
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  2. ; ; ; ; ; ( , Journal of Biogeography)
    Abstract Aim

    Fossil data may be crucial to infer biogeographical history, especially in taxa with tropical trans‐Pacific distributions. Here, we use extinct and extant trochanteriid flattened spiders to test hypotheses that could explain its trans‐Pacific disjunct distribution, including a Boreotropical origin with a North Atlantic dispersal, an African origin with South Atlantic dispersal and an Eurasian origin with Bering Bridge route.

     Location

    World‐wide.

     Taxon

    Trochanteriidae,Plator‐Doliomalus‐Vectius(PDV) clade.

     Methods

    MicroCT was used to collect morphological data from an undescribed Baltic amber fossil. These data were used with additional fossils and extant species in a total‐evidence, tip‐dated phylogenetic analysis. We tested different scenarios using constrained dispersal matrices in a Bayesian approach. An analysis with fossils pruned was also performed to explore how lack of fossil data might impact inferences of biogeographical process.

     Results

    The phylogenetic analyses allowed us to place the new fossil in the genusPlator. Analyses without fossils suggest an African origin with a dispersal to Asia from India and a South Atlantic dispersal to South America. When fossils are included, hypothesis‐testing rejects this scenario and equally supports a Boreotropical and an Afro‐European origin with a South Atlantic route and a dispersal to Asia from Europe.

     Main conclusions

    Biogeographical inferences of disjunctly distributed taxa should be interpreted with caution when fossils are not included. Although one alternative hypothesis was not completely rejected, results show that the Boreotropical hypothesis for the PDV clade could be a robust explanation for its actual distribution. This hypothesis is mostly overlooked in animal taxa and rigorous tests with other taxa with similar distributions may reveal that a Boreotropical origin is common. We discuss methodological approaches that could improve biogeographical tests using fossils as terminals.

     
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