Looking into the Past: The Diversification of Amphibians in the Neotropical Savannas

Aim: Reveal the evolutionary processes that contributed to biotic diversification in the Cerrado savanna using amphibians as a model. Evolutionary patterns were investigated by comparing the phylogeographic and biogeographic history of biome-specific yet widely distributed amphibian species (<em>Chiasmocleis albopunctata, Dendropsophus rubicundulus</em> and <em>Physalaemus nattereri</em>). Location: Cerrado region, central South America. Methods: I sampled thousands of loci randomly distributed throughout the genomes of all three species. I applied phylogenetic, phylogeographic, demographic, and coalescent species delimitation methods to these molecular data, in combination with species distribution modeling for the past, in order to resolve questions of evolutionary history, taxonomic diversity, species boundaries, and test hypotheses that implicate climatic (stable/unstable) and geomorphological events (plateau/valley) in the formation of this diversity. Results: The <em>C. albopuntata</em> species group is distributed in the Bolivian and Brazilian savannas and Chaco and it is comprised of at least tree species <em>C. albopunctata, C. mehelyi</em>, and a composite lineage that includes: <em>C. bicegoi, C. centralis</em>, and <em>C.</em> sp. The Cerrado species <em>C. centralis, D. rubicundulus</em> and <em>P. nattereri</em> were each found to have three distinct, genetic populations widely distributed in the Neotropical savannas. No patterns of genetic differentiation related to geomorphology (plateau vs. valley populations) nor climatic stability in any of the species was observed. The demographic models indicate the presence of migration between populations, demonstrating that there are no important geographic barriers to gene flow. Conclusions: The results highlight the likely influence of the Atlantic Forest as the source for <em>C. albopunctata</em> species group inhabiting the dry open areas of the Neotropical savannas. The further uplift of the Brazilian shield during the Pliocene and Pleistocene was an important event for diversification of <em>C. centralis, D. rubicundulus</em> and <em>P. nattereri</em>, and the isolation by distance also promoted the differentiation among the populations of <em>C. centralis, D. rubicundulus</em> and <em>P. nattereri</em>, in combination with the climatic fluctuations during the Quaternary.

Name thesis:degree_name

Ph.D. in Biological Science

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biology

Year dc:date.available

2019

Author dc:creator

• da Costa Arantes, Ísis

Contributors dc:contributor

• Brice P. Noonan
• Guarino Colli
• Ryan Garrick

• anurans
• biogeography
• Cerrado
• comparative phylogeography
• open areas
• species delimitation
• Biology

Repository record dc:identifier

https://egrove.olemiss.edu/etd/1567

OAI identifier oai:identifier

oai:egrove.olemiss.edu:etd-2566