title: Phylogenetic and size constrains on cranial ontogenetic allometry of spiny rats (Echimyidae, Rodentia).
abstract: Analysis of ontogenetic development is crucial for understanding the emergence of phenotypic discrepancies between animal taxa. The study of allometric trajectories within a phylogenetic context is a feasible approach to assess the morphological change across different evolutionary lineages. Here, we report the disparity of multivariate ontogenetic allometry in the Echimyidae, a taxonomically diverse rodent family, as well as the effects of size on the evolution of skull ontogeny. The ontogenetic trajectories of 15 echimyid operational taxonomic unities (12 genera plus one genus with three species) belonging to all subfamilies and major clades, when plotted in allometric space, revealed strong and significant phylogenetic signals. Allometric trajectories were found to be constrained by phylogenetic ancestry, with changes approximately adjusting to a Brownian motion model of evolution. Moreover, the occupation of allometric space by echimyid taxa was significantly correlated with adult size rather than with shape, suggesting that the variation in adult size might result in critically intrinsic and structural constraints on allometric coefficients. These findings disagreed with the hypothesis that allometric disparities might be mainly adaptive with undetectable phylogenetic signals.
authors.affiliation: Departamento de Zoologia, CCS, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.|Programa de Genética, Instituto Nacional de Câncer, Rio de Janeiro, Brazil.|Departamento de Genética, CCS, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: W C
authors.initials: WC
authors.lastname: Tavares
authors.affiliation: Departamento de Zoologia, CCS, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. pessoa@acd.ufrj.br.
authors.forename: L M
authors.initials: LM
authors.lastname: Pessôa
authors.affiliation: Programa de Genética, Instituto Nacional de Câncer, Rio de Janeiro, Brazil.|Departamento de Genética, CCS, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: H N
authors.initials: HN
authors.lastname: Seuánez
mesh_terms: D000818:Animals; D005075:Biological Evolution; D049628:Body Size; D010802:Phylogeny; D051381:Rats; D012377:Rodentia / Q000235:genetics*; D012886:Skull / Q000033:anatomy & histology*
keywords: Octodontoidea; caviomorph; development; skull