Ecological Opportunity and Incumbency in the Diversification of Repeated Continental Colonizations by Muroid Rodents
Why some clades are more species-rich than others is a central question in macroevolution. Most hypotheses explaining exceptionally diverse clades involve the emergence of an ecological opportunity caused by a major biogeographic transition or evolution of a key innovation. The radiation of muroid r...
| Published in: | Systematic Biology |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | unknown |
| Published: |
Oxford University Press (OUP)
2013
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| Subjects: | |
| Online Access: | http://academic.oup.com/sysbio/article-pdf/62/6/837/24579075/syt050.pdf https://doi.org/10.1093/sysbio/syt050 https://academic.oup.com/sysbio/article/62/6/837/1710000 https://pubmed.ncbi.nlm.nih.gov/23925508/ https://www.ncbi.nlm.nih.gov/pubmed/23925508 http://sysbio.oxfordjournals.org/content/early/2013/08/06/sysbio.syt050 https://works.bepress.com/john-schenk/5/ https://academic.microsoft.com/#/detail/2101475581 |
| Summary: | Why some clades are more species-rich than others is a central question in macroevolution. Most hypotheses explaining exceptionally diverse clades involve the emergence of an ecological opportunity caused by a major biogeographic transition or evolution of a key innovation. The radiation of muroid rodents is an ideal model for testing theories of diversification rates in relation to biogeography and ecological opportunity because the group is exceptionally species- rich (comprising nearly one-third of all mammal species), it is ecologically diverse, and it has colonized every major landmass except New Zealand and Antarctica, thus providing multiple replicate radiations. We present an extension of the conventional ecological opportunity model to include a geographic incumbency effect, develop the largest muroid phylogeny to date, and use this phylogeny to test the new model. The nearly 300-species phylogeny based on four nuclear genes is robustly resolved throughout. Consistent with the fossil record, we identified Eurasia as the most likely origin of the group and reconstructed five to seven colonizations of Africa, five of North America, four of Southeast Asia, two of South America, two of Sahul, one of Madagascar, and eight to ten recolonizations of Eurasia. We accounted for incomplete taxon sampling by using multiple statistical methods and identified three corroborated regions of the tree with significant shifts in diversification rates. In several cases, higher rates were associated with the first colonization of a continental area, but most colonizations were not followed by bursts of speciation. We found strong evidence for diversification consistent with the ecological opportunity model (initial burst followed by density-dependent slowdown) in the first colonization of South America and partial support for this model in the first colonization of Sahul. Primary colonizers appear to inhibit the ultimate diversity of secondary colonizers, a pattern of incumbency that is consistent with ecological ... |
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