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| Aim The ocellated lizards of the genus Timon, comprising six species that are
distributed across continental Asia, Europe and Africa, offer an interesting
model to study the evolution of ecological niches through comparative phylo-
climatic analysis. Our study provides insights into the evolutionary history of
the ocellated lizards and helps to understand the role of climatic niche evolu-
tion during the speciation process.
Location Eastern and western margins of the Mediterranean basin.
Methods A dated molecular phylogeny was estimated based on three mito-
chondrial and two nuclear genes. Using multivariate statistics, species distribu-
tion models were developed to characterize the Grinnellian niches of all
species. Subsequently, ancestral environmental niche occupancy of each taxon
was reconstructed using niche occupancy pro?les. Niche divergence among
species was quanti?ed by computing multivariate niche overlaps via two-
dimensional and n-dimensional approaches.
Results Phylogenetic analysis supports that the ancestor of Timon diverged
into the eastern and western groups following multiple vicariance events that
shaped the current distribution pattern of Palaearctic lizards. High complexity
in the ecological niche evolution between the Mediterranean and non-Mediter-
ranean climatic regions was detected. The generally low niche divergence
among members of the eastern group and the remarkable climatic divergence
within the western group highlight an important role of temperature seasonal-
ity in a Mediterranean and Atlantic climate context. The results also suggest
niche conservatism in terms of microhabitats described by vegetation cover.
Main conclusions The ocellated lizards provide an interesting example of a
vertebrate radiation where niche shift (with or without vicariance) and niche
conservatism alternate in different niche axes shaping current biogeographical
patterns. | |
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