Data and script from: Contingent evolution of thick enamel by kangaroos to resist dietary abrasion

This dryad submission includes data and code written in the R language
needed to analyse dental and diversity data for marsupial and placental
herbivores. The primary data set are measurements of lower molar tooth
enamel thickness and tooth shape from numerous extant and fossil kangaroo
species representing 41 Australian fossil assemblages. These measurements
are derived from microCT scans of dentaries or isolated lower molars. For
each fossil assemblage analysed, estimated ages in million years and
geological subepochs are assigned. Dental data for fossil and extant
kangaroo species include linear measurements of enamel thickness from
seven tooth regions, measurements of whole crown enamel volume,
measurements of crown dentine volume, and surface area measurements of
enamel–dentine junction area. In addition to measurements of dental tissue
dimensions, measurements of the inclination of molar tooth lophs and
relative depth of the lophs are also included. R code is provided to plot
trends in these data through time based on time bin categorisations and
across the kangaroo phylogeny using a composite tree of prior studies.
Data on tooth shape and dental tissue thickness for kangaroos are
augmented by data compiled from the literature for primates in order to
compare the degree of convergence between these two groups. To analyse
this, R code is provided which compares the relative investment in enamel
volume and body mass between marsupials and primates based on regression
analysis. To contextualize trends in the evolution of enamel thickness
among kangaroos with other herbivore groups, trends in the diversity of
both marsupial and placental herbivores (generic richness) are analysed
through time. Diversity data on marsupial herbivores are based on records
compiled by previous publications, whereas for placental herbivores, they
are derived from the Paleobiology Database. R code is provided to analyses
major trajectories in generic richness of marsupial and placental
herbivores through time, especially with respect to chewing behaviors.