‘The Pleistocenic Arc Theory and Legume studies: ¿Que veinte años no es nada?’

PRADO, D.E.; MOGNI, V.Y.; OAKLEY, L.J.

Buenos Aires

Simposio; V Internacional Legumes Conference – Advances in the XXI Century. Phytogeography Symposium; 2010

Sociedad Argentina de Botánica

‘ THE PLEISTOCENIC ARC THEORY AND LEGUME STUDIES: ARE 20 YEARS JUST NOTHING? THE PLEISTOCENIC ARC THEORY AND LEGUME STUDIES: QUE VEINTE AÑOS NO ES NADA? Darién E. Prado, Virginia Y. Mogni & Luis J. Oakley Botánica, Facultad de Ciencias Agrarias, UNR. Campo Villarino, C.C. 14, S2125ZAA Zavalla, Santa Fe, Argentina; dprado@unr.edu.ar Stated for the first time in 1991, the Pleistocenic Arc Theory sustains that present day disjunct fragments of dry forests in central tropical South America (extending from NE Brazil south to NE Argentina and eastern Paraguay, through the Chiquitania to SW Bolivia and finally dry inter Andean valleys in Peru and Ecuador), bear witness of a previously more continuous expansion of these forests during the Upper Pleistocenic, disrupted by dry-cold versus humid-warm climatic cycles. During the last 20 years research on Legume taxa have flourished, both as classical taxonomic revisions and molecular studies and phylogenies. Whereas the distribution patterns of Neotropical legumes are still overall mostly coincidental with the originally found that generated the hypothesis, the published phylogenies either are ambiguous or indicate a much older diversification date than Pleistocene. The evidence accumulated for and against the theory is here briefly reviewed.