DOI: 10.5061/dryad.487
title: Data from: Linked morphological changes during palate evolution in early tetrapods

description: We examined the shapes and sizes of dermal bones of the palate of selected
 Palaeozoic tetrapods in order to identify the ancestral states of palatal
 bone morphologies in the earliest tetrapods, to learn how the composition
 of the palate varies within and among early tetrapod radiations, and
 recognize evolutionary correlations among the size and shapes of skeletal
 elements in this important group of animals. We find that whereas the
 palatal bones themselves and their arrangements are usually conserved,
 considerable correlated evolutionary change occurs in the shapes and sizes
 of the bones. Some of the changes in the bones are allometrically linked
 to overall palate size, which varies more than 100-fold among the taxa in
 our sample. Often, these allometries were only hinted at in traditional
 independent contrasts-based regressions of log transformed data,
 particularly because many allometries are subtle, their slopes may vary
 among subclades, and the scatter around some trendlines is high. Rather,
 the allometries showed up in analyses of size-standardized palatal bone
 dimensions investigated using independent contrasts, bivariate
 phylomorphospace plots, and mirrored character reconstructions on the
 phylogenetic tree. We find negative allometry for parasphenoid lengths and
 widths essentially across the entire tree of Palaeozoic tetrapods, but
 with different trajectories characterizing the two largest clades, the
 temnospondyls and the lepospondyls. The lengths of several other elements
 may show positive allometries, either across the entire tree or in just a
 subclade. One possible positive allometry exists for the ectopterygoid,
 which appears to allometrically shorten in temnospondyls that evolve small
 body and palate size, and, as in Doleserpeton can be lost altogether. Both
 shortening and loss could be by the same developmental change,
 paedomorphosis, a form of heterochrony. Paedomorphosis might also account
 for evolution of relatively large parasphenoids in both lepospondyls and
 diminutive temnospondyls, but does not seem to explain evolution of
 ectopterygoid loss in lepospondyls. A regularity observed across nearly
 all taxa in our study set is an inverse correlation between the lengths of
 the vomer and pterygoid, bones that lie adjacent to one another along the
 long palatal axis. Further work is needed to learn whether such correlated
 evolution might be due to adaptation and/or to developmental bias, and
 particularly, to learn how correlations and allometries themselves evolve.
description: Kimmel, et al. phylogeny
 and linked morphometric dataMESQUITE NEXUS file
 containing the phylogeny and linked morphometric data used in Kimmel,
 Sidlauskas and Clack 2009.KimmelJofAnat.nexusPalate Reconstructions.TIF file containing images of all palate reconstructions used in Kimmel, Sidlauskas and Clack, 2009, Journal of Anatomy. Individual palate elements are shown in separate colors. Note that the full data package (including phylogeny and linked morphometric data) is available at http://hdl.handle.net/10255/dryad.487Kimmel_etal_palates_composite_archive.tif