Abstract
Brazilian continental islands represent a natural laboratory to study speciation driven by recent phenotypic and genotypic divergence. The Bothrops jararaca species group is distributed in the Brazilian Atlantic Forest and on most of the Brazilian continental islands. The group is currently composed of the mainland common lancehead (B. jararaca) and four insular species (B. alcatraz, B. insularis, B. otavioi, and B. sazimai). Here, we evaluate mitochondrial DNA and morphological diversity of the B. jararaca species group and aim to provide additional evidence to understand insularization processes on the Brazilian coast. Our results, interpreted together with a comprehensive review of geomorphological data, provide a new conceptual framework for understanding the colonization process of the Brazilian continental islands. This framework suggests a history of multiple rounds of periodic isolation and reconnection between insular populations and their mainland relatives throughout the last 420,000 years. Furthermore, although some insular populations may have speciated prior to the last glacial maximum, other species likely diverged within the last 11,000 years. Additionally, the repeated evolution of size and dietary shift in the B. jararaca species group suggests a remarkable case of convergent adaptation. Our study provides evidence that the Bothrops from Ilha da Moela (Brazilian state of São Paulo) represents an undescribed species, presenting a distinct phenotype, and an exclusive history of isolation and adaptation. We describe this unique lancehead as a new species and we suggest it should be listed as critically endangered based on its endemicity to a small island that is severely impacted by constant and longstanding human presence.
http://zoobank.org/urn:lsid:zoobank.org:pub:B1F65287-CEC4-4F9C-90D7-42314A497590
Acknowledgments
We are grateful to the following colleagues for their help at Laboratório de Coleções Zoológicas of Instituto Butantan: Valdir J. Germano, Flora R. Ortiz, Bruno Rocha, and Frederico Alcântara Menezes. We wish to thank Pollyana Campos, Nancy da Rós, Gesiele A. Barros-Carvalho, and Inácio L. M. Junqueira-de-Azevedo from Laboratório Especial de Toxinologia Aplicada (LETA) of Instituto Butantan for their help generating part of the molecular data. We are also indebted to Danusa Maia, Fernando Silva, Flora R. Ortiz, José Thales Portillo, Lucas Amâncio, Paulo Cicchi, Paulo Machado Filho, Weverton Azevedo, and Silvia T. Cardoso for their help during field expeditions. We thank to H. Lisle Gibbs and Andrew J. Mason for comments and suggestions on important aspects of this paper. We also thank the anonymous reviewers and the associate editor for all comments and suggestions that significantly improved the final version of our paper. Finally, we wish to thank the constant support provided by the Brazilian Navy, specifically the logistic support provided by CPSP (Capitania dos Portos de São Paulo) during the field expeditions in the Moela Island.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Supplemental material
Supplemental material for this article can be accessed here: https://doi.org/10.1080/14772000.2021.2017059
Collecting permits
The specimens were collected in accordance with Brazilian laws, under the permit provided by Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio; SISBIO permit numbers 57585 and 66597).
Associate Editor: David Gower