Data from: Phylogeny, ecology and deep time: 2D outline analysis of anuran skulls from the Early Cretaceous to Recent

Anurans have a long fossil record, spanning from the Early Jurassic to
Recent. However, specimens are often severely flattened, limiting their
inclusion in quantitative analyses of morphological evolution. We perform
a two-dimensional morphometric analysis of anuran skull outlines,
incorporating 42 Early Cretaceous to Miocene species, as well as 93 extant
species in 32 families. Outlines were traced in tpsDig2 and analysed with
elliptical Fourier analysis. Fourier coefficients were used in MANOVAs,
phylogenetic MANOVAs (as significant phylogenetic signal was found) and
disparity analyses across multiple ecological and life history groupings.
The Neotropical realm showed higher disparity than the Australian,
Palearctic and Oriental realms (p = 0.007, 0.013, 0.038, respectively),
suggesting concordance of disparity and diversity. Developmental strategy
had a weak effect on skull shape (R2 = 0.02, p = 0.039), and disparity was
similar in metamorphosing and direct developing frogs. Ecological niche
was a significant discriminator of skull shape (F = 1.43, p = 0.004), but
not after phylogenetic correction. Evolutionary allometry had a small but
significant influence on the cranial outlines of the combined extant and
fossil dataset (R2 = 0.05, p = 0.004). Finally, morphospace occupation
appears to have changed over time (F = 1.59, p = 5 × 10-10). However, as
with ecological signal, this shift appears to be largely driven by
phylogeny and was not significant after phylogenetic correction (R2 =
0.26, p = 0.22). This study thus suggests that frog skull evolution is
shaped more by phylogenetic constraints than by ecology.