Multiple continental radiations and correlates of diversification in Lupinus (Leguminosae): testing for key innovation with incomplete taxon sampling
- PMID: 22228799
- PMCID: PMC3329764
- DOI: 10.1093/sysbio/syr126
Multiple continental radiations and correlates of diversification in Lupinus (Leguminosae): testing for key innovation with incomplete taxon sampling
- PMID: 22228799
- PMCID: PMC3329764
- DOI: 10.1093/sysbio/syr126
Abstract
Replicate radiations provide powerful comparative systems to address questions about the interplay between opportunity and innovation in driving episodes of diversification and the factors limiting their subsequent progression. However, such systems have been rarely documented at intercontinental scales. Here, we evaluate the hypothesis of multiple radiations in the genus Lupinus (Leguminosae), which exhibits some of the highest known rates of net diversification in plants. Given that incomplete taxon sampling, background extinction, and lineage-specific variation in diversification rates can confound macroevolutionary inferences regarding the timing and mechanisms of cladogenesis, we used Bayesian relaxed clock phylogenetic analyses as well as MEDUSA and BiSSE birth-death likelihood models of diversification, to evaluate the evolutionary patterns of lineage accumulation in Lupinus. We identified 3 significant shifts to increased rates of net diversification (r) relative to background levels in the genus (r = 0.18-0.48 lineages/myr). The primary shift occurred approximately 4.6 Ma (r = 0.48-1.76) in the montane regions of western North America, followed by a secondary shift approximately 2.7 Ma (r = 0.89-3.33) associated with range expansion and diversification of allopatrically distributed sister clades in the Mexican highlands and Andes. We also recovered evidence for a third independent shift approximately 6.5 Ma at the base of a lower elevation eastern South American grassland and campo rupestre clade (r = 0.36-1.33). Bayesian ancestral state reconstructions and BiSSE likelihood analyses of correlated diversification indicated that increased rates of speciation are strongly associated with the derived evolution of perennial life history and invasion of montane ecosystems. Although we currently lack hard evidence for "replicate adaptive radiations" in the sense of convergent morphological and ecological trajectories among species in different clades, these results are consistent with the hypothesis that iteroparity functioned as an adaptive key innovation, providing a mechanism for range expansion and rapid divergence in upper elevation regions across much of the New World.
Figures
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Diversity of life forms and…
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Diversity of life forms and ecologies in Lupinus from western North America (a–i)…
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MCCT for Lupinus recovered from…
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MCCT for Lupinus recovered from unconstrained Bayesian MCMC tree searches in BEAST under…
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MCCT for Lupinus showing diversification…
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MCCT for Lupinus showing diversification rates ( r = lineages/myr) estimated under the…
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Ancestral state reconstructions and BiSSE…
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Ancestral state reconstructions and BiSSE analyses of correlated diversification for (a) life history…
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Distributions of (a) annual and…
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Distributions of (a) annual and (b) perennial Lupinus in western North America (cf.…
References
-
- Ackerly DD. Taxon sampling, correlated evolution, and independent contrasts. Evolution. 2000;54:1480–1492. - PubMed
-
- Ackerly DD, Schwilk DW, Webb CO. Niche evolution and adaptive radiation: testing the order of trait divergence. Ecology. 2006;87:S50–S61. - PubMed
-
- Badgley C. Tectonics, topography and mammalian diversity. Ecography. 2010;33:220–231.
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