In the jaws of a titan: 3D comparative anatomy of the mandibles of the Canary giant lizards (Gallotiinae: Gallotia )

Abstract

An iconic, insular, endemic genus of lizards (Gallotia) is present on the Canary Islands (Spain), comprising gigantic to smaller-sized species. Despite numerous studies on various biological aspects of this genus, the osteological knowledge available is scarce. This makes it difficult to identify to species level the bone remains recovered from both living and extinct taxa, which is essential to understanding the evolution of this genus through time, its distribution and its migratory patterns. Herein, a detailed description, comparison and discussion of each mandibular bone of all the living giant species and the fossil taxon G. goliath is presented. First detailed descriptions of G. intermedia and G. bravoana are presented, and interspecific and ontogenetic characters to be considered for Gallotia and related taxa in future works are proposed. Disentangling the intra- and interspecific variability of the mandible, as well as its ontogenetic changes through time, is of special interest for a variety of reasons. These include: a) to evaluate paleobiodiversity; b) to evaluate intraspecific variation and ontogenetic changes; c) to establish mandibular characters for specific identification; d) as previous step in performing computational biomechanics studies based on 3D models to shed in-depth light on feeding ecology.