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Luiz Jardim De Queiroz

Postdoctoral fellow in Animal evolution and conservation

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  • office 4081a (Sciences III)
  • Evolutionary units delimitation and continental multilocus phylogeny of the hyperdiverse catfish genus Hypostomus. Molecular phylogenetics and evolution vol. 145 (2020): 106711. doi:10.1016/j.ympev.2019.106711

    abstract

    With 149 currently recognized species, Hypostomus is one of the most species-rich catfish genera in the world, widely distributed over most of the Neotropical region. To clarify the evolutionary history of this genus, we reconstructed a comprehensive phylogeny of Hypostomus based on four nuclear and two mitochondrial markers. A total of 206 specimens collected from the main Neotropical rivers were included in the present study. Combining morphology and a Bayesian multispecies coalescent (MSC) approach, we recovered 85 previously recognized species plus 23 putative new species, organized into 118 'clusters'. We presented the Cluster Credibility (CC) index that provides numerical support for every hypothesis of cluster delimitation, facilitating delimitation decisions. We then examined the correspondence between the morphologically identified species and their inter-specific COI barcode pairwise divergence. The mean COI barcode divergence between morphological sisters species was 1.3±1.2%, and only in 11% of the comparisons the divergence was ≥ 2%. This indicates that the COI barcode threshold of 2% classically used to delimit fish species would seriously underestimate the number of species in Hypostomus, advocating for a taxon-specific COI-based inter-specific divergence threshold to be used only when approximations of species richness are needed. The phylogeny of the 108 Hypostomus species, together with 35 additional outgroup species, confirms the monophyly of the genus. Four well-supported main lineages were retrieved, hereinafter called super-groups: Hypostomus cochliodon, H. hemiurus, H. auroguttatus, and H. plecostomus super-groups. We present a compilation of diagnostic characters for each super-group. Our phylogeny lays the foundation for future studies on biogeography and on macroevolution to better understand the successful radiation of this Neotropical fish genus.

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  • Multifactorial genetic divergence processes drive the onset of speciation in an Amazonian fish. PLoS ONE 2017 ;12(12):e0189349. 10.1371/journal.pone.0189349. PONE-D-17-12071.

    abstract

    Understanding the processes that drive population genetic divergence in the Amazon is challenging because of the vast scale, the environmental richness and the outstanding biodiversity of the region. We addressed this issue by determining the genetic structure of the widespread Amazonian common sardine fish Triportheus albus (Characidae). We then examined the influence, on this species, of all previously proposed population-structuring factors, including isolation-by-distance, isolation-by-barrier (the Teotônio Falls) and isolation-by-environment using variables that describe floodplain and water characteristics. The population genetics analyses revealed an unusually strong structure with three geographical groups: Negro/Tapajós rivers, Lower Madeira/Central Amazon, and Upper Madeira. Distance-based redundancy analyses showed that the optimal model for explaining the extreme genetic structure contains all proposed structuring factors and accounts for up to 70% of the genetic structure. We further quantified the contribution of each factor via a variance-partitioning analysis. Our results demonstrate that multiple factors, often proposed as individual drivers of population divergence, have acted in conjunction to divide T. albus into three genetic lineages. Because the conjunction of multiple long-standing population-structuring processes may lead to population reproductive isolation, that is, the onset of speciation, we suggest that the multifactorial population-structuring processes highlighted in this study could account for the high speciation rate characterising the Amazon Basin.

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