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.
This paper presents data on aspects of the reproductive ecology of a population of Podarcis bocagei in northwestern Spain, as monitored over a two‐year period (1990–1991) Data were obtained principally on the basis of mark‐recapture experiments, but also from laboratory hatching studies Mating took place between the end of March and July During the laying period, from May to July, 8 5% of reproductive females produced three clutches, 52 1% two clutches, and 39 4% one clutch In general, single clutches were produced by small females Only a small proportion of large females produced three clutches Mean clutch size was 4 8 eggs (range 4–7) in May, 4 3 (2–6) in June and 3 9 (2–4) in July There was sigmficant variation in the mean snout‐to‐vent length (SVL) of females laying in each month of the season Both clutch size and mean single‐egg volume increased with mother's SVL There was a significant partial correlation between egg volume and clutch size when both mother's SVL and month of laying were held constant There was no significant between‐year variation in clutch size, breeding females' SVL, egg weight or relative clutch mass A delay in the timing of reproductive events in one year (1991) is attributable to adverse weather conditions during early spring Hatching occurred between July and September Hatch success (as estimated in 1989, 1990 and 1991 from natural nests at the study site) was high, ranging from 83% in 1991 to 91% in 1989 The mean SVL of female hatchlings was greater than that of male hatchlings By contrast, adult females had lower mean SVL than adult males
Species that contain populations with different reproductive modes offer excellent opportunities to study the transition between such strategies. Salamandra salamandra (Linnaeus, 1758) is one of two species within the Salamandra-Lyciasalamandra clade which displays two reproductive modes simultaneously. Along the S. salamandra distribution, the common reproductive mode is ovoviviparity although the species also has viviparous populations in the northern Iberian Peninsula. The occurrence of viviparity has recently been reported in two small offshore island populations on the Atlantic coast (NW Iberia), which originated after the last glacial period (8000-9000 years ago). In this paper, we analysed ovoviviparous, hybrid and viviparous populations (inland and mainland) from 17 localities across the northern Iberian Peninsula using two mitochondrial markers (Cyt b and COI, c. 1100 bp). Phylogenetic and phylogeographic analyses highly support that viviparity arose as an evolutionary novelty in the S. salamandra island populations and that viviparous populations are therefore not monophyletic. The recent insularity of Atlantic island populations leads us to conclude that the transition from ovoviviparity to viviparity can happen in a very short-time span. Additionally, to determine the likely source of this evolutionary transition, we discuss how ecological pressures could have an effect on the maintenance of the ovoviviparous reproductive mode. Hence, taking into account the results of this study, we propose the consideration of the island populations as an evolutionary unit for conservation purposes.
Satellite DNAs compose a large portion of all higher eukaryotic genomes. The turnover of these highly repetitive sequences is an important element in genome organization and evolution. However, information about the structure and dynamics of reptilian satellite DNA is still scarce. Two satellite DNA families, HindIII and TaqI, have been previously characterized in four species of the genus Iberolacerta. These families showed different chromosomal locations, abundances, and evolutionary rates. Here, we extend the study of both satellite DNAs (satDNAs) to the remaining Iberolacerta species, with the aim to investigate the patterns of variability and factors influencing the evolution of these repetitive sequences. Our results revealed disparate patterns but also common traits in the evolutionary histories of these satellite families: (i) each satellite DNA is made up of a library of monomer variants or subfamilies shared by related species; (ii) species-specific profiles of satellite repeats are shaped by expansions and/or contractions of different variants from the library; (iii) different turnover rates, even among closely related species, result in great differences in overall sequence homogeneity and in concerted or non-concerted evolution patterns, which may not reflect the phylogenetic relationships among taxa. Contrasting turnover rates are possibly related to genomic constraints such as karyotype architecture and the interspersed organization of diverging repeat variants in satellite arrays. Moreover, rapid changes in copy number, especially in the centromeric HindIII satDNA, may have been associated with chromosomal rearrangements and even contributed to speciation within Iberolacerta.
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