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TACT: Taxonomic Addition for Complete Trees

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TACT is a Python app for stochastic polytomy resolution. It uses birth-death-sampling estimators across an ultrametric phylogeny to generate branching times for unsampled taxa, using taxonomic information to compatibly place new taxa onto a backbone phylogeny.

Getting started with TACT


TACT is described more fully in its manuscript. If you use TACT, please cite:

  • Chang, J., Rabosky, D. L., & Alfaro, M. E. (2019). Estimating diversification rates on incompletely-sampled phylogenies: theoretical concerns and practical solutions. Systematic Biology. doi:10.1093/sysbio/syz081

TACT owes its existence to much foundational work in the area of stochastic polytomy resolution, namely PASTIS and CorSiM.

  • Thomas, G. H., Hartmann, K., Jetz, W., Joy, J. B., Mimoto, A., & Mooers, A. O. (2013). PASTIS: an R package to facilitate phylogenetic assembly with soft taxonomic inferences. Methods in Ecology and Evolution, 4(11), 1011–1017. doi:10.1111/2041-210x.12117

  • Cusimano, N., Stadler, T., & Renner, S. S. (2012). A New Method for Handling Missing Species in Diversification Analysis Applicable to Randomly or Nonrandomly Sampled Phylogenies. Systematic Biology, 61(5), 785–792. doi:10.1093/sysbio/sys031


Please consider sponsoring the ongoing maintenance of TACT via GitHub Sponsors.

Initial development was supported by a National Science Foundation Doctoral Dissertation Improvement Grant (DEB-1601830).