Using landmark data to study changes in developing time along a phylogeny

CATALANO, S; GONZÁLEZ, MARINA; ESCAPA IGNACIO,; RAMÍREZ ROZZI, FERNANDO; GONZÁLEZ JOSÉ, ROLANDO

Encuentro; Meeting of the Willi Hennig Society; 2011

When changes in morphological characters along a phylogeny are studied, it is usual to consider the same stage of development for all species. In general, adult stages are ubiquitously studied. However, changes in the developmental timing (i.e. heterochrony) are a source of evolutionary novelties that can potentially generate, for instance, that the adult morphology of one species is similar to the juvenile morphology of its ancestor. We have recently proposed a method (Catalano et al 2010) to analyze changes in shape (represented by landmark configurations) along a phylogeny considering parsimony as optimality criterion. Here we present an extension of that method that allows analyzing changes in shape where the homology in development stages is not pre-defined. We tested the method in a dataset comprising the cranial morphology of great apes (Hominidae). The results gave support to the hypothesis of a neotenic origin for the cranial morphology in Homo.