Model-based analysis supports interglacial refugia over long-dispersal events in the diversification of two South American cactus species

Author(s)

Perez, M. F. ^[1] ; Bonatelli, I. A. S. ^[1] ; Moraes, E. M. ^[1] ; Carstens, B. C. ^[2]

Affiliation

^[1] Univ Fed Sao Carlos, Dept Biol, Rod Joao Leme dos Santos Km 110, BR-18052780 Sorocaba, SP - Brazil

^[2] Ohio State Univ, Dept Evolut Ecol & Organismal Biol, Columbus, OH 43210 - USA

• Document type: Journal article
• Source: HEREDITY; v. 116, n. 6, p. 550-557, JUN 2016.
• Web of Science Citations: 8

Abstract

Pilosocereus machrisii and P. aurisetus are cactus species within the P. aurisetus complex, a group of eight cacti that are restricted to rocky habitats within the Neotropical savannas of eastern South America. Previous studies have suggested that diversification within this complex was driven by distributional fragmentation, isolation leading to allopatric differentiation, and secondary contact among divergent lineages. These events have been associated with Quaternary climatic cycles, leading to the hypothesis that the xerophytic vegetation patches which presently harbor these populations operate as refugia during the current interglacial. However, owing to limitations of the standard phylogeographic approaches used in these studies, this hypothesis was not explicitly tested. Here we use Approximate Bayesian Computation to refine the previous inferences and test the role of different events in the diversification of two species within P. aurisetus group. We used molecular data from chloroplast DNA and simple sequence repeats loci of P. machrisii and P. aurisetus, the two species with broadest distribution in the complex, in order to test if the diversification in each species was driven mostly by vicariance or by long-dispersal events. We found that both species were affected primarily by vicariance, with a refuge model as the most likely scenario for P. aurisetus and a soft vicariance scenario most probable for P. machrisii. These results emphasize the importance of distributional fragmentation in these species, and add support to the hypothesis of long-term isolation in interglacial refugia previously proposed for the P. aurisetus species complex diversification. (AU)

• FAPESP's process: 10/02665-1 - Study of the genetic structure of the columnar cacti Pilosocereus machrisii using microsatellite DNA.
• Grantee: Manolo Fernandez Perez
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 10/02186-6 - Analysis of phylogeographic structure of Pilosocereus machrisii (Cactaceae) using molecular markers of the chloroplast genome (cpDNA)
• Grantee: Isabel Aparecida da Silva Bonatelli
• Support Opportunities: Scholarships in Brazil - Master