To cite phytools in a publication please use:

  Revell, L. J. (2024) phytools 2.0: an updated R ecosystem for
  phylogenetic comparative methods (and other things). PeerJ, 12,
  e16505.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {{p}hytools 2.0: an updated {R} ecosystem for phylogenetic comparative methods (and other things).},
    author = {Liam J. Revell},
    journal = {PeerJ},
    year = {2024},
    volume = {12},
    pages = {e16505},
    doi = {10.7717/peerj.16505},
  }

As phytools is continually evolving you may also want to cite its
version number (found with 'library(help = phytools)' or
'packageVersion("phytools")').