To cite package 'paleotree' in publications use:
Bapst, David W. (2012). paleotree: an R package for paleontological and phylogenetic analyses of evolution. Methods Ecol. Evol. 3: 803-807. doi:10.1111/j.2041-210X.2012.00223.x
As paleotree is continually evolving, you may want to cite its version number. Find it with 'help(package=paleotree)'.
Corresponding BibTeX entry:
@Manual{, title = {paleotree: Paleontological and Phylogenetic Analyses of Evolution}, author = {David W. Bapst}, year = {2012}, }