Statistical Analysis
As the majority of DMTA variables are not normally distributed
(Shapiro-Wilk tests, Table 1) we used non-parametric statistical
tests (Kruskal-Wallis) to compare differences among all taxa or pits
for species and temporal comparisons, respectively. We used
Dunn’s procedure [55] to conduct multiple comparisons (either
between taxa or between like taxa across time) absent of the
Bonferroni correction. As the Bonferroni correction is meant to
reduce the likelihood of false positives (Type I errors) by taking
into consideration the number of comparisons being made, it also
increases the probability of false negatives (Type II errors) [56–57].
Furthermore, we do not want the number of extant and/or extinct
comparisons to affect statistical differences between taxa; thus, the
Bonferroni correction is not appropriate for our comparisons.
Additionally, we compared ranked data for all species pairs using
both Fisher (LSD) and Tukey (HSD) tests and report these results
in Table S2, noting deviations from Dunn’s procedure when