Amphitropical disjunctions in New World Menthinae: Three Pliocene dispersals to South America following late Miocene dispersal to North America from the Old World

Abstract

Although three New World Menthinae genera occur in both North and South America, none exhibit an amphitropical disjunction. However, three clades exhibit amphitropical disjunctions, all dating to the early Pliocene, and all involve jump dispersals to either southeastern or southwestern South America from southeastern North America.

Tracking temporal shifts in area, biomes, and pollinators in the radiation ofSalvia(sages) across continents: leveraging anchored hybrid enrichment and targeted sequence data

“…The diversification of Salvia throughout Mexico and then subsequently further south into Central and South America is a history of specialization to pollinators, both bee and hummingbird. This diversification mirrors that seen in the South American radiation of subtribe Menthinae, one of the sister lineages to subtribe Salviinae, in which hummingbird pollination, especially in arid biomes, was important (Drew and Sytsma, ; Drew et al., ). However, this diversification in pollinator modes in Salvia has four unusual attributes.…”

“…Stochastic mapping suggests that this involved expansion first to the Mediterranean from Southwest Asia and then to eastern North America, presumably as long‐distance dispersal via the North Atlantic Land Bridge (see also Will and Claßen‐Bockhoff, ). This bridge was especially suitable geologically and climatically for temperate migrations into the Miocene (Manchester, ; Tiffney and Manchester, ; Milne, ; Tiffney, ), and probably late Miocene (Denk et al., ; Drew et al., ). This dispersal event was followed by a limited diversification of six Salvia species into eastern and southern North American coniferous forests, grasslands, and arid biomes.…”

“…Current and prevailing geological evidence argues for an early Pleistocene closure (O'Dea et al., ), although minimally “stepping‐stone” islands may have existed between North America and South America earlier in the Miocene (Wegner et al., ; Montes et al., , ). On the other hand, phylogenetic chronograms from a growing list of plant clades point to earlier—late Miocene or Pliocene—movements across the Isthmus of Panama (Bacon et al., , ; see Drew et al., , for discussion in context of the Menthineae). Salvia now can be added to this list, as our results indicate many independent jump dispersal (and some back dispersal) events across the Isthmus region starting as early as 12 Ma in the mid‐Miocene and continuing through the Pliocene (Fig.…”

Pleistocene range expansions might explain striking disjunctions between eastern Brazil, Andes and Mesoamerica inLeandras.str. (Melastomataceae)

“…The neotropical flora is still understudied and, perhaps, similar patterns (eastern Brazil/Mesoamerica) in other groups might be reported as their taxonomy and distributions are updated. While some intercontinental disjunctions are easily explained, at least in part, by ancient vicariance, patterns involving widely distant populations, occurring in areas that were never in physical proximity, nor bridged by a common vegetation type or climatic regime, such the amphitropical ones, cannot be readily explained by vicariance (Drew et al, 2017). For most standard amphitropical disjuncts, bird migrations are interpreted as drivers of such patterns (Schenk & Saunders, 2017).…”

“…Among the abovementioned patterns, the disjunctions observed in Leandra s.str., especially the one involving Mesoamerica and eastern Brazil, does not match exactly any of the previously described patterns, but roughly approaches the temperate disjuncts within the amphitropical pattern (Raven, ). Recently, some phylogenetic driven studies have explored the origin and evolution of the American amphitropical disjunctions (Vargas et al, ; Wen et al, ; Simpson et al, ; Moore et al, ; Drew et al, ; Simpson et al, ). Hypotheses to explain the origin of the amphitropical disjunctions include vicariance, island hopping, and long‐distance dispersal.…”