Análisis panbiogeográfico del género Galianthe subgénero Ebelia (Rubiaceae)

Abstract

Galianthe (Rubiaceae: Spermacoceae) is a genus composed by the subgenus Galianthe and Ebelia, the latter includes 11 Neotropical species with a center of diversity located in Brazil. The panbiogeographic analysis emphasizes the importance of the spatial dimension of biodiversity to generate a better understanding of both, evolutionary patterns and processes. Panbiogeography focuses on vicariant events as the greatest force for the fragmentation of biota. There are few studies leading with the biogeography of Galianthe, so the aim of this study is to establish the distribution patterns of subgenus Ebelia by track analysis. The species belonging to Ebelia have Mesoamerican, Andean and Chacoan distribution, with four of the species endemic of Brazil. Seven species form a unique generalized track called "Parana", which connects the biogeographic provinces Cerrado and Chaco of Chacoan dominion, and Atlantic, Parana and Araucaria Forest, belonging to the Parana dominion. Both dominions belong to the Chacoan subregion of the Neotropical region. Because the origin of the Spermacoceae tribe has been established during the Eocene, the aridification of South America, generated by the vicariant events as Andean orogeny and marine introgression have possibly favoured the adaptive radiation of the subgenus Ebelia within the Chacoan subregion.