Phylogeny and systematics of jararacussu species group of Bothrops (Serpentes, Crotalinae), with test of biogeographic hypothesis to the past connection Amazonia-Atlantic Forest

Author(s)

Francisco Humberto Dal Vechio Filho

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2019-05-03

Examining board members

Miguel Trefaut Urbano Rodrigues; Felipe Franco Curcio; Silvio Shigueo Nihei; Paulo Gustavo Homem Passos

• Advisor: Miguel Trefaut Urbano Rodrigues

Abstract

The hypotetized historical contact Amazon-Atlantic Forest has been recurrently cited in the literature for several groups of Neotropical fauna and would have occurred by different geographic routes and time periods. According to this hypothesis, in hot and humid periods the forests expanded causing retraction / fragmentation of the open areas, while in cold and dry periods, the reverse would occur. Thus, by using Neotropical pit vipers as a model, this thesis aims to: (1) test the historical forest contact Amazon-Atlantic Forest, as well as the time of separation between relict lineages in these forested environments, elucidating the demographic history of Bothrops species from jararacussu group, atrox group and B. bilineatus; (2) Crotalus durissus, a species associated with the diagonal of open areas of South America (Caatinga, Cerrado and Chaco), was used in parallel to test the occurrence of expansion of these environments, which would lead to the breakage of the hypothetical Amazon-Atlantic Forest forested bridge. Phylogenetic and phylogeographic relationships between samples of Bothrops and Crotalus were tested through a multi-locus dataset (four mitochondrial genes and five nuclear) under Bayesian Inference. Alternative historical scenarios were tested based on coalescent simulations and ABC (approximate Bayesian computation). In addition, was inferred independently evolving lineages to recognized species diversity in each group studied, using Bayesian implementation of the molecular species delimitation algorithm Generalized Mixed Yule-Coalescent. Phylogenetic results and analyzes of species delimitation indicate cryptic diversity for the groups jararacussu, atrox and taeniatus. The tests of historical scenarios suggest (1) multiple Amazon-Atlantic Forest forest connections in the last 2.5 million years, with faunal exchange in both directions and (2) expansion of the open areas of the Cerrado and Caatinga in temporal synchrony with loss of forest bridge Amazon-Atlantic Forest during late Pleistocene (3) that the formation and stabilization of the Amazon River influenced the diversification of the jararacussu group, generating diversity. The results provide information on the historical dynamism of forested and open landscapes in the Neotropics over time, as well as the role of Amazonian rivers in the diversification of fauna. Moreover, the results point to taxonomic instability and cryptic diversity in several groups within Brothrops and Crotalus durissus, revealing the need for systematic deepening for these medically important venemous snakes (AU)

• FAPESP's process: 14/24431-3 - Phylogeny and systematic review of the species of the Bothrops jararacussu group (Squamata, Crotalinae) and phylogeography of B. jararacussu Lacerda, 1884, with biogeographic hypotheses test for the existence of past forest contact Amazon- Atlantic Forest
• Grantee: Francisco Humberto Dal Vechio Filho
• Support Opportunities: Scholarships in Brazil - Doctorate