Ecophylogeography of the disjunct Chaco tree species Prosopis chilensis (Fabaceae)

AGUILAR, D.; ACOSTA M. C.; BARANZELLI, M.; VERGA, A.; SÉRSIC, A.N.; DELATORRE-HERRERA, J.; COSACOV, A.

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2020

0024-4066

The intraspecific evolutionary history of South American xerophytic plant species has been poorly explored. The tree species Prosopis chilensis has a disjunct distribution in four South American regions: southern Peru, southern Bolivia, central-western Argentina and central Chile. Here, we combined phylogeographical (based on chloroplast and nuclear markers), morphological and climatic data to evaluate the relative contribution of historical demo-stochastic and adaptive processes in differentiating the disjunct areas of distribution. The results obtained with both molecular markers revealed two closely related phylogroups (Northern and Southern, predominating in Bolivian Chaco and in Argentine Chaco/Monte, respectively), which would have diverged at around 5 Mya, probably associated with the Paranaense sea transgression. Bolivia and Argentina have a higher number of exclusive haplotypes/alleles and higher molecular diversity than Chile, suggesting a long-lasting in situ persistence in the former and a relatively recent colonization in the latter, from the Bolivian and Argentinian lineages. The two main lineages differ in morphology and climatic niche, revealing two significant, independent evolutionary units within P. chilensis promoted by local adaptation and geographical isolation.