Diversification of the Amazonian Flora and its Relation to key Geological and Environmental Events: A Molecular Perspective

Abstract

This chapter provides a molecular perspective on Neogene plant diversifi cation in the Amazon drainage basin. The history of Amazon plant diversifi cation must be understood in a broader context of migration of lineages from other continents during the Neogene and earlier periods. The history of major migration events, as revealed by recent molecular systematics research, is reviewed here. These studies demonstrate the role of land bridge migration and oceanic dispersal in forming contemporary Amazon plant diversity. Many of the diversifi cation histories coincide geographically and in timing with the uplift period of the Andean orogeny and, in some cases, with Pleistocene climatic changes. Although the Pleistocene history of Amazon vegetation is poorly understood, population genetics approaches may help to elucidate the occurrence of population contractions and expansions and their relation to putative moist forest refuges during glacial periods. The overlay of ecological traits, such as soil or habitat preference, onto phylogenies highlights the role of habitat specialization in plant diversifi cation across the Amazon drainage basin. This review suggests that collaboration between molecular systematists, ecologists, geologists and palaeobotanists will advance future research on the driving factors of Amazon plant diversifi cation.

Phylogenetic insights into Andean plant diversification

“…In this line, Hoorn et al (2011) argued that crown node ages of clades "lead to more robust age estimation of deeper nodes even when many species are missing." However, disentangling the relative effects of different events that overlap in time may prove impossible using dated phylogenies (Pennington and Dick, 2010).…”

Phylogeography of the Mantled Howler Monkey (Alouatta palliata; Atelidae, Primates) across Its Geographical Range by Means of Mitochondrial Genetic Analyses and New Insights about the Phylogeny of Alouatta

“…The ρ statistic is unbiased and highly independent of past demographic events. This approach is named "borrowed molecular clocks" and uses direct nucleotide substitution rates inferred from other taxa [Pennington and Dick, 2010]. Thus, we used 1e mutation each 195,000 years for the howler monkeys following an average value for different mitochondrial genes obtained for different primate taxa [Ashley and Vaughn, 1995;Ruiz-García et al, 2016a].…”

Dispersal assembly of rain forest tree communities across the Amazon basin

“…Large-scale geological events that subdivide populations would lead to congruent geographic phylogenetic patterns across lineages, but there is little evidence suggesting common deep imprints of geological events in Amazonian tree phylogenies. For example, a geographic phylogenetic structure across the Miocene Pebas wetlands is not detected in the phylogenies of Inga, Swartzia, Guatteria, or Protieae; instead, geographic patterns are particular to lineages, reflecting a primacy for idiosyncratic historical dispersal in generating distributions (25,53). The lack of congruent patterns suggests that allopatric speciation involving population vicariance caused by common geological factors is unlikely.…”