Environmental temperatures shape thermal physiology as well as diversification and genome-wide substitution rates in lizards.

Climatic conditions changing over time and space shape the evolution of organisms at multiple levels, including temperate lizards in the family Lacertidae. Here we reconstruct a dated phylogenetic tree of 262 lacertid species based on a supermatrix relying on novel phylogenomic datasets and fossil calibrations. Diversification of lacertids was accompanied by an increasing disparity among occupied bioclimatic niches, especially in the last 10 Ma, during a period of progressive global cooling. Temperate species also underwent a genome-wide slowdown in molecular substitution rates compared to tropical and desert-adapted lacertids. Evaporative water loss and preferred temperature are correlated with bioclimatic parameters, indicating physiological adaptations to climate. Tropical, but also some populations of cool-adapted species experience maximum temperatures close to their preferred temperatures. We hypothesize these species-specific physiological preferences may constitute a handicap to prevail under rapid global warming, and contribute to explaining local lizard extinctions in cool and humid climates.

Allopatric diversification and evolutionary melting pot in a North African Palearctic relict: The biogeographic history of Salamandra algira.

North Africa is a climatically and topographically complex region with unique biotic assemblages resulting from the combination of multiple biogeographic realms. Here, we assess the role of climate in promoting intra-specific diversification in a Palearctic relict, the North African fire salamander, Salamandra algira, using a combination of phylogenetic and population genetic analyses, paleoclimatic modelling and niche overlap tests. We used mitochondrial DNA (Cyt-b), 9838 ddRADseq loci, and 14 microsatellite loci to characterize patterns of genetic diversity and population structure. Phylogenetic analyses recover two major clades, each including several lineages with mito-nuclear discordances suggesting introgressive patterns between lineages in the Middle Atlas, associated with a melting pot of genetic diversity. Paleoclimatic modelling identified putative climatic refugia, largely matching areas of high genetic diversity, and supports the role of aridity in promoting allopatric diversification associated with ecological niche conservatism. Overall, our results highlight the role of climatic microrefugia as drivers of populations' persistence and diversification in the face of climatic oscillations in North Africa, and stress the importance of accounting for different genomic regions when reconstructing biogeographic processes from molecular markers.

Cytogenetic Characterization of a Population of Acanthodactylus lineomaculatus Duméril and Bibron, 1839 (Reptilia, Lacertidae), from Southwestern Morocco and Insights into Sex Chromosome Evolution.

Acanthodactylus lineomaculatus is now regarded as an ecotype of A. erythrurus with which it has been recently synonymized. Despite the wide range of A. erythrurus, karyological data for this species are scarce and limited to classical cytogenetic studies carried out in individuals from only 2 locations (central Spain and Spanish enclave of Melilla on the northwestern Mediterranean Moroccan coast). Here, for the first time, we cytogenetically characterized individuals of A. lineomaculatus from the southwestern Moroccan Atlantic coast with the aim to increase the karyological knowledge of this wide-ranging species and to assess if any chromosomal changes can be found in this ecotype in comparison to other populations of this species. The diploid number of the individuals investigated is 2n = 38 which is typical of most lacertids. Active NORs were located telomerically in a medium-small pair of chromosomes, and no inactive NORs were detected. C-banding revealed an intensely heterochromatic W chromosome composed of AT-rich (centromere and long arm telomeric region) and GC-rich (most of the long arm) regions, with extended interstitial telomeric sequences. These telomere-like repeats occupy the GC-rich heterochromatin of the W. The DNA composition of the W represents a trait distinguishing A. lineomaculatus (southwestern Morocco) from A. erythrurus from Spain that possess a DAPI-positive (AT-rich) W chromosome. In conclusion, these results add further evidence to the remarkable karyotype conservation in lacertid lizards, although differences in NOR location and in W chromosome structure among populations could suggest an incipient speciation mediated by chromosome changes in this wide-ranging lizard species.