Quantitative developmental data in a phylogenetic framework

Abstract

Following the embryonic period of organogenesis, most development is allometric growth, which is thought to produce most of the evolutionary morphological divergence between related species. Bivariate or multivariate coefficients of allometry are used to describe quantitative developmental data and are comparable across taxa; as such, these coefficients are amenable to direct treatment in a phylogenetic framework. Mapping of actual allometric coefficients onto phylogenetic trees is supported on the basis of the evolving nature of growth programs and the type of character (continuous) that they represent. This procedure depicts evolutionary allometry accurately and allows for the generation of reliable reconstructions of ancestral allometry, as shown here with a previously published case study on rodent cranial ontogeny. Results reconstructed the signature allometric patterns of rodents to the root of the phylogeny, which could be traced back into a (minimum) Paleocene age. Both character and statistical dependence need to be addressed, so this approach can be integrated with phylogenetic comparative methods that deal with those issues. It is shown that, in this particular sample of rodents, common ancestry explains little allometric variation given the level of divergence present within, and convergence between, major rodent lineages. Furthermore, all that variation is independent of body mass. Thus, from an evolutionary perspective, allometry appears to have a strong functional and likely adaptive basis.

Postmetamorphic ontogenetic allometry and the evolution of skull shape in Nest‐building frogs Leptodactylus (Anura: Leptodactylidae)

“…Allometric patterns and how they influence head development have been explored in several tetrapod clades, including urodelans (Ivanović & Arntzen, ; Ivanović, Cvijanović, & Kalezić, ; Ivanović et al, ), caecilians (Sherratt et al, ), squamates (Esquerré et al, ; Hipsley & Müller, ; Openshaw & Keogh, ; Urošević, Ljubisavljević, & Ivanović, ), turtles (Wilson & Sánchez Villagra, ), birds (Klingenberg & Marugán‐Lobón, ), and diverse mammalian groups (e.g., Cardini, Polly, Dawson, & Milne, ; Flores, Giannini, & Abdala, ; Giannini, ; Gonzalez, Perez & Bernal, ; Segura, Cassini, & Prevosti, ). In this context, our results provide some hints to interpret the relationships among body size evolution, adult skull shape, and skull ontogeny in species of the anuran genus Leptodactylus .…”

“…Compared to small-sized frogs, small-sized newts have different patterns of skull allometry (i.e., they show in general high shape/size change rates; Ivanović et al, 2007). The lack of a clear effect of adult absolute body size on skull allometry was also found in rodents (Giannini, 2014), suggesting that allometric divergence can be also highly adaptive.…”

Evolution of extreme ontogenetic allometric diversity and heterochrony in pythons, a clade of giant and dwarf snakes

“…Allometry and size-shape relationships have been considered constraints that size and growth impose to the morphologies that organisms can adopt (Simpson 1944;Gould and Lewontin 1979;Maynard Smith et al 1985). Yet, allometric trajectories themselves can be biological traits under selection and not just constraints (Weber 1990;Frankino et al 2005;Adams and Nistri 2010;Wilson and Sanchez-Villagra 2010;Klingenberg 2010;Urošević et al 2013;Porto et al 2013;Giannini 2014).…”

Comparative cranial ontogeny of Tapirus (Mammalia: Perissodactyla: Tapiridae)

“…Two of these variables (MZL, CBL) were statistically allometric in one species and isometric in the other, their actual intervals overlapped, meaning that they did not differ in evolutionary terms (i.e. they would be reconstructed as sharing an interval in their common hypothetical ancestor; see Giannini, , for details).…”