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OpenTreeChronograms: a database of phylogenetic trees with branch lengths proportional to time

Welcome to OpenTreeChronograms GitHub repository!

OpenTreeChronograms is an R package that hosts a chronogram database assembled with data from the Open Tree of Life phylogenetic database, the Phylesystem.

OpenTreeChronograms has been developed to work along with the datelife R package.

README topics:

Local installation of the OpenTreeChronograms R package

OpenTreeChronograms’s most recent stable version can be installed with:


OpenTreeChronograms’s previous stable versions are available for installation from the CRAN repository. For example, to install version 2022.01.28, you can run:

devtools::install_version("OpenTreeChronograms", version="2022.01.28")

You can install OpenTreeChronograms’s development version from its GitHub repository with:


Loading the database

data("opentree_chronograms", package = "OpenTreeChronograms")

[1] “2022.01.28”


[1] “2022-01-28 15:24:53 PST”

Citing OpenTreeChronograms

If you use OpenTreeChronograms for a publication, please cite the Open Tree of Life database Phylesystem, the OpenTreeChronograms R package, the accompanying paper, and all chronograms used.


This package is free and open source software, licensed under GPL.


OpenTreeChronograms was developed and is maintained as part of the Datelife project, funded by the phylotastic and the Open Tree of Life projects.