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Guillory WX, de Medeiros Magalhães F, Coelho FEA, Bonatelli IAS, Palma-Silva C, Moraes EM, Garda AA, Burbrink FT, Gehara M. Geoclimatic drivers of diversification in the largest arid and semi-arid environment of the Neotropics: Perspectives from phylogeography. Mol Ecol 2024:e17431. [PMID: 38877815 DOI: 10.1111/mec.17431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 05/24/2024] [Accepted: 05/30/2024] [Indexed: 06/16/2024]
Abstract
The South American Dry Diagonal, also called the Diagonal of Open Formations, is a large region of seasonally dry vegetation extending from northeastern Brazil to northern Argentina, comprising the Caatinga, Cerrado, and Chaco subregions. A growing body of phylogeography literature has determined that a complex history of climatic changes coupled with more ancient geological events has produced a diverse and endemic-rich Dry Diagonal biota. However, the exact drivers are still under investigation, and their relative strengths and effects are controversial. Pleistocene climatic fluctuations structured lineages via vegetation shifts, refugium formation, and corridors between the Amazon and Atlantic forests. In some taxa, older geological events, such as the reconfiguration of the São Francisco River, uplift of the Central Brazilian Plateau, or the Miocene inundation of the Chaco by marine incursions, were more important. Here, we review the Dry Diagonal phylogeography literature, discussing each hypothesized driver of diversification and assessing degree of support. Few studies statistically test these hypotheses, with most support drawn from associating encountered phylogeographic patterns such as population structure with the timing of ancient geoclimatic events. Across statistical studies, most hypotheses are well supported, with the exception of the Pleistocene Arc Hypothesis. However, taxonomic and regional biases persist, such as a proportional overabundance of herpetofauna studies, and the under-representation of Chaco studies. Overall, both Pleistocene climate change and Neogene geological events shaped the evolution of the Dry Diagonal biota, though the precise effects are regionally and taxonomically varied. We encourage further use of model-based analyses to test evolutionary scenarios, as well as interdisciplinary collaborations to progress the field beyond its current focus on the traditional set of geoclimatic hypotheses.
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Affiliation(s)
- Wilson X Guillory
- Department of Earth and Environmental Sciences, Rutgers University Newark, Newark, New Jersey, USA
- Department of Biological Sciences, Rutgers University Newark, Newark, New Jersey, USA
| | | | | | - Isabel A S Bonatelli
- Departamento de Ecologia e Biologia Evolutiva, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, São Paulo, Brazil
| | - Clarisse Palma-Silva
- Departamento de Biologia Vegetal, Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz, Campinas, São Paulo, Brazil
| | - Evandro M Moraes
- Departamento de Biologia, Universidade Federal de São Carlos (UFSCar), Sorocaba, São Paulo, Brazil
| | - Adrian Antonio Garda
- Departamento de Botânica e Zoologia, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Frank T Burbrink
- Department of Herpetology, The American Museum of Natural History, New York City, New York, USA
| | - Marcelo Gehara
- Department of Earth and Environmental Sciences, Rutgers University Newark, Newark, New Jersey, USA
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Coelho FEA, Guillory WX, Gehara M. Coalescent simulations indicate that the São Francisco River is a biogeographic barrier for six vertebrates in a seasonally dry South American forest. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.983134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The riverine barrier hypothesis has been extensively explored in Neotropical rainforests, while its importance in drier regions such as the Caatinga, a seasonally dry tropical forest in northeastern Brazil, has only recently received more attention. The Caatinga is bisected by the São Francisco River (SFR), which has long been suggested to be an important biogeographic feature in the region. However, recent studies have found mixed support for the role of the SFR as a hard barrier, most of them relying on the presence or absence of genetic breaks congruent with its course. Here, we used published multilocus and next-generation data from six vertebrate species to test the SFR’s strength as a barrier. Using model-based approaches (approximate Bayesian computation and supervised machine learning), we tested demographic models incorporating full, intermediate, and zero migration across the SFR, estimating divergence times and migration rates for each species. We found support for the SFR’s role as a barrier, allowing gene flow for some species. Estimated divergence times varied among species but are limited to the late Pleistocene, coherent with one of several proposed paleocourse changes in the river’s geological history. Contrary to the mixed results of previous studies, our study supports the SFR as an important phylogeographic barrier across different taxonomic groups, driving diversification in the Caatinga.
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Affiliation(s)
- Michael Goodin
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, United States of America
- * E-mail:
| | - Antonia Dos Reis Figueira
- Universidade Federal de Lavras, Departamento de Fitopatologia, Caixa, CEP, Lavras, Minas Gerais, Brasil
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