Interface to the 'Open Tree of Life' API

An interface to the 'Open Tree of Life' API to retrieve phylogenetic trees, information about studies used to assemble the synthetic tree, and utilities to match taxonomic names to 'Open Tree identifiers'. The 'Open Tree of Life' aims at assembling a comprehensive phylogenetic tree for all named species.

rotl is an R package to interact with the Open Tree of Life data APIs. It was initially developed as part of the NESCENT/OpenTree/Arbor hackathon.

Client libraries to interact with the Open Tree of Life API also exists for Python and Ruby.

The current stable version is available from CRAN, and can be installed by typing the following at the prompt in R:


If you want to test the development version, you first need to install ghit (ghit is a more lightweight version of devtools if your sole purpose is to install packages that are hosted on GitHub).


Then you can install rotl using:

library(ghit) # or library(devtools)

There are three vignettes:

  • Start by checking out the "How to use rotl?" by typing: vignette("how-to-use-rotl", package="rotl") after installing the package.

  • Then explore how you can use rotl with other packages to combine your data with trees from the Open Tree of Life project by typing: vignette("data_mashups", package="rotl").

  • The vignette "Using the Open Tree Synthesis in a comparative analsysis" demonstrates how you can reproduce an analysis of a published paper by downloading the tree they used, and data from the supplementary material: vignette("meta-analysis", package="rotl").

The vignettes are also available from CRAN: How to use rotl?, Data mashups, and Using the Open Tree synthesis in a comparative analysis.

Taxonomic names are represented in the Open Tree by numeric identifiers, the ott_ids (Open Tree Taxonomy identifiers). To extract a portion of a tree from the Open Tree, you first need to find ott_ids for a set of names using the tnrs_match_names function:

apes <- c("Pan", "Pongo", "Pan", "Gorilla", "Hoolock", "Homo")
(resolved_names <- tnrs_match_names(apes))
##   search_string unique_name approximate_match ott_id is_synonym flags
## 1           pan         Pan             FALSE 417957      FALSE      
## 2         pongo       Pongo             FALSE 417949      FALSE      
## 3           pan         Pan             FALSE 417957      FALSE      
## 4       gorilla     Gorilla             FALSE 417969      FALSE      
## 5       hoolock     Hoolock             FALSE 712902      FALSE      
## 6          homo        Homo             FALSE 770309      FALSE      
##   number_matches
## 1              1
## 2              1
## 3              1
## 4              1
## 5              1
## 6              1

Now we can get the tree with just those tips:

tr <- tol_induced_subtree(ott_ids=ott_id(resolved_names))

The code above can be summarized in a single pipe:

## or expressed as a pipe:
c("Pan", "Pongo", "Pan", "Gorilla", "Hoolock", "Homo") %>%
    tnrs_match_names %>%
    ott_id %>%
    tol_induced_subtree %>%

Starting with v3.0.0 of the package, the major and minor version numbers (the first 2 digits of the version number) will be matched to those of the API. The patch number (the 3rd digit of the version number) will be used to reflect bug fixes and other changes that are independent from changes to the API.

rotl can be used to access other versions of the API (if they are available) but most likely the high level functions will not work. Instead, you will need to parse the output yourself using the "raw" returns from the unexported low-level functions (all prefixed with a .). For instance to use the tnrs/match_names endpoint for v2 of the API:

rotl:::.tnrs_match_names(c("pan", "pango", "gorilla", "hoolock", "homo"), otl_v="v2")

Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.


  • Fix tests and vignette to reflect changes accompanying release 6.1 of the synthetic tree

  • Add section in vignette "How to use rotl?" about how to get the higher taxonomy from a given taxon.

  • Add CITATION file with MEE manuscript information (#82)

  • rotl now interacts with v3.0 of the Open Tree of Life APIs. The documentation has been updated to reflect the associated changes. More information about the v3.0 of the Open Tree of Life APIs can be found on their wiki.
  • New methods: tax_sources, is_suppressed, tax_rank, unique_name, name, ott_id, for objects returned by tnrs_match_names(), taxonomy_taxon_info(), taxonomy_taxon_mrca(), tol_node_info(), tol_about(), and tol_mrca(). Each of these methods have their own class.

  • New method tax_lineage() to extract the higher taxonomy from an object returned by taxonomy_taxon_info() (initally suggested by Matt Pennell, #57).

  • New method tol_lineage() to extract the nodes towards the root of the tree.

  • New print methods for tol_node_info() and tol_mrca().

  • New functions study_external_IDs() and taxon_external_IDs() that return the external identifiers for a study and associated trees (e.g., DOI, TreeBase ID); and the identifiers of taxon names in taxonomic databases. The vignette "Data mashup" includes an example on how to use it.

  • The function strip_ott_id() gains the argument remove_underscores to remove underscores from tips in trees returned by OTL.

  • Rename method ott_taxon_name() to tax_name() for consistency.

  • Rename method synth_sources() and study_list() to source_list().

  • Refactor how result of query is checked and parsed (invisible to the user).

  • Fix bug in studies_find_studies(), the arguments verbose and exact were ignored.

  • The argument only_current has been dropped for the methods associated with objects returned by tnrs_match_names()

  • The print method for tnrs_context() duplicated some names.

  • inspect(), update() and synonyms() methods for tnrs_match_names() did not work if the query included unmatched taxa.

  • New vignette: meta-analysis

  • Added arguments include_lineage and list_terminal_descendants to taxonomy_taxon()

  • Improve warning and format of the result if one of the taxa requested doesn't match anything tnrs_match_names.

  • In the data frame returned by tnrs_match_names, the columns approximate_match, is_synonym and is_deprecated are now logical (instead of character) [issue #54]

  • New utility function strip_ott_ids removes OTT id information from a character vector, making it easier to match tip labels in trees returned by tol_induced_subtree to taxonomic names in other data sources. This function can also remove underscores from the taxon names.

  • New method list_trees returns a list of tree ids associated with studies. The function takes the output of studies_find_studies or studies_find_trees.

  • studies_find_studies and studies_find_trees gain argument detailed (default set to TRUE), that produces a data frame summarizing information (title of the study, year of publication, DOI, ids of associated trees, ...) about the studies matching the search criteria.

  • get_study_tree gains argument deduplicate. When TRUE, if the tree returned for a given study contains duplicated tip labels, they will be made unique before being parsed by NCL by appending a suffix (_1, _2, _3, etc.). (#46, reported by @bomeara)

  • New method get_study_year for objects of class study_meta that returns the year of publication of the study.

  • A more robust approach is used by get_tree_ids to identify the tree ids in the metadata returned by the API

  • Initial CRAN release on July, 24th 2015

Reference manual

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3.0.1 by Francois Michonneau, 5 months ago

Report a bug at

Browse source code at

Authors: Francois Michonneau [aut, cre], Joseph Brown [aut], David Winter [aut]

Documentation:   PDF Manual  

Task views: Phylogenetics, Especially Comparative Methods

BSD_2_clause + file LICENSE license

Imports httr, jsonlite, assertthat, rncl, ape, rentrez

Suggests knitr, rmarkdown, testthat, RNeXML, phylobase, MCMCglmm, fulltext, readxl

Imported by taxize.

See at CRAN