Testing geological models of evolution of the Isthmus of Panama in a phylogenetic framework

Abstract

The emergence and closure of the Isthmus of Panama had regional and global impacts that were rivalled by few other Cenozoic geological events. The closure of the Central American Seaway and the rise of the Isthmus had dramatic affects on climate and air and oceanic currents worldwide. Formation of the Isthmus also drove terrestrial biotic interchange, ending the isolation of South America by permitting the mixing of its biota with that of North and Central America. A dated phylogenetic tree of a well‐sampled clade of palms in the tribe Trachycarpeae (Copernicia, Pritchardia and Washingtonia) was used to conduct biogeographical analyses. Examination of the timing of lineage dispersal from North into South America was performed and two contrasting temporal hypotheses of the Isthmus formation were tested: occurrence in the Pliocene (c. 5 Mya to the present) or in the Miocene (prior to c. 5 Mya). Copernicia is inferred to have dispersed through the Isthmus of Panama region into South America and subsequently into the Caribbean, where it underwent a rapid radiation. Consistent with a geologically older age for the Isthmus than previously understood, our results support recent geological and palaeobiological data that suggest an early Oligocene to early Miocene model of evolution of the Isthmus of Panama. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, ••, ••–••.

The Cenozoic Cooling – continental signals from the Atlantic and Pacific side of Eurasia

“…Recent data regarding plate tectonics, exhumation history, and phylogenetic studies point to an even earlier, at least intermittent, disappearance of the CAS, at ca. 15 Ma (Montes et al, 2012;Bacon et al, 2013;cf. Fig.…”

The emerging field of geogenomics: Constraining geological problems with genetic data

“…A major flaw in this argument, however, is that palms and many other tropical tree taxa (Cody et al, 2010) do not require land bridges to disperse over marine barriers. This is evidenced by the extreme geographic dispersal of members of the same palm clade to Hawaii and South Pacific and Caribbean islands (Bacon et al, 2013). Nevertheless, similar application of molecular clocks could address the dynamic responses of both marine and nonmarine organisms in relationship to isthmus closure (Jackson et al, 1993).…”

“…In support of an older Isthmus of Panama, Bacon et al (2013) attributed relatively early divergence of Central and South American palms to an earlier landbridge available for palm dispersal. A major flaw in this argument, however, is that palms and many other tropical tree taxa (Cody et al, 2010) do not require land bridges to disperse over marine barriers.…”

Reply to Lessios and Marko et al.: Early and progressive migration across the Isthmus of Panama is robust to missing data and biases

“…Recent efforts have shed light on the geological formation of the Isthmus of Panama and its impact on the region's biodiversity, climate, and oceanic circulation (9,10). However, many intriguing aspects remain to be fully understood, such as why organisms varied in migration time, which ecosystems dominated through time, and how sea level and climatic changes affected the Great American Biotic Interchange (11).…”