Big, time-scaled phylogenies are fundamental to connecting evolutionary processes to modern biodiversity patterns. Yet inferring reliable phylogenetic trees for thousands of species involves numerous trade-offs that have limited their utility to comparative biologists. To establish a robust evolutionary timescale for all approximately 6,000 living species of mammals, we developed credible sets of trees that capture root-to-tip uncertainty in topology and divergence times. Our “backbone-and-patch” approach to tree building applies a newly assembled 31-gene supermatrix to two levels of Bayesian inference: (1) backbone relationships and ages among major lineages, using fossil node or tip dating, and (2) species-level “patch” phylogenies with nonoverlapping in-groups that each correspond to one representative lineage in the backbone. Species unsampled for DNA are either excluded (“DNA-only” trees) or imputed within taxonomic constraints using branch lengths drawn from local birth–death models (“completed” trees). Joining time-scaled patches to backbones results in species-level trees of extant Mammalia with all branches estimated under the same modeling framework, thereby facilitating rate comparisons among lineages as disparate as marsupials and placentals. We compare our phylogenetic trees to previous estimates of mammal-wide phylogeny and divergence times, finding that (1) node ages are broadly concordant among studies, and (2) recent (tip-level) rates of speciation are estimated more accurately in our study than in previous “supertree” approaches, in which unresolved nodes led to branch-length artifacts. Credible sets of mammalian phylogenetic history are now available for download at http://vertlife.org/phylosubsets, enabling investigations of long-standing questions in comparative biology.
Long celebrated for its spectacular landscapes and strikingly high levels of endemic biodiversity, the Philippines has been studied intensively by biogeographers for two centuries. Concentration of so many endemic land vertebrates into a small area and shared patterns of distribution in many unrelated forms has inspired a search for common mechanisms of production, partitioning, and maintenance of life in the archipelago. In this review, we (a) characterize an ongoing renaissance of species discovery, (b) discuss the changing way biogeographers conceive of the archipelago, (c) review the role molecular phylogenetic studies play in understanding the evolutionary history of Philippine vertebrates, and (d) describe how a 25-year Pleistocene island connectivity paradigm continues to provide some explanatory power, but has been augmented by increased understanding of the archipelago's geological history and ecological gradients. Finally, we (e) review new insights provided by studies of adaptive versus nonadaptive radiation and phylogenetic perspectives on community ecology. 412 Brown et al.
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