How important was polyploidy in the diversification of herbs in the Chaquean Domain? The case of the Turnera sidoides autopolyploid complex (Passifloraceae: Turneroideae)

SOLÍS NEFFA, VIVIANA G; MORENO, E M SARA; SILVA, GISELLA C; KOVALSKY, I EVELIN; VIA DO PICO, GISELA M; ALMIRÓN, EMILIA N A; ROGGERO LUQUE, JUAN M; FERNÁNDEZ, SILVIA A; PAREDES, ESTEBAN N; CHALUP, LAURA M I; ROBLEDO DOBLADEZ, GERMÁN A; SEIJO, J GUILLERMO

BOTANICAL JOURNAL OF THE LINNEAN SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2022 vol. 199 p. 286 - 311

0024-4074

The evolutionary processes that shape the unique biodiversity of the Neotropical Chaquean Domain are still poorly understood. Choosing an appropriate model to address evolutionary questions is essential for understanding the current patterns of the Chaquean diversity. We used Turnera sidoides autopolyploid complex as a model to assess current and past environmental factors and the processes that shaped and maintain its intraspecific variation in the Chaquean Domain. Based on current and past niche modelling, cytogeographic and genetic divergence analyses we provided strong evidence that T. sidoides complex is in an active process of intraspecific allopatric diversification at diploid level since the early Pleistocene. Further diversification of the complex involved the emergence of independent polyploid series in each morphologically divergent lineage. Cytotypes within each series do not differ in diagnostic morphological traits, but are reproductively isolated and have different ecological requirements. Currently, each subspecies / morphotype and cytotype are true species according to the biological, evolutionary or ecological concepts; however, they are still considered to be the same morphological species. Turnera sidoides revealed the complex processes of diversification occurring at the Chaquean Domain and the large amount of diversity that is overlooked when the morphological species concept is only considered to estimate the diversity of the Neotropical ecoregions.