Evolutionary Responses of Caudates to Climatic Changes in Pliocene Spain: Insights from the Camp dels Ninots Lagerstätte

Caudates, one of three extant lineages of amphibians, are a rich and diverse clade that rely heavily on water for reproduction and development and are known to be important palaeoecological indicators. Records indicate that less than 10% of Neogene caudates are known to be preserved as articulated skeletons, and in Lagerstätte type of preservation is even rarer still. This study will investigate caudates from the Camp del Ninots Lagerstätte using micro-computed tomography scans (μCT) to build a taxonomic framework and use three-dimensional geometric morphometrics to analyse shape differences for phylogenetic/taxonomic value. This study will also compare morphological shape differences using μCT of caudates from different sexes and determine whether there are sexual dimorphic morphological characters within Spanish caudates. Morphological characters and genomic data will be combined to identify Pliocene aged caudates recovered from the Camp del Ninots Lagerstätte using Bayesian phylogenetics, which will provide time-calibrations of when the Spanish fossil caudates originated in comparison to extant congeners. Caudates identified by Bayesian phylogenetic methods will then act as fossil calibration points to phylogeographically determine how caudates dispersed spatio-temporally into Spain from Africa or the rest of Europe. It is hoped that this research can improve our understanding of caudate evolution in the Neogene, but also how we can project caudate responses to climatic change in the future and mitigate biodiversity loss.