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In this article an introduction is given on the geological history leading to the separation of Podarcis lilfordi (GÜNTHER, 1874) and Podarcis pityusensis (BOSCÁ, 1883) as separate species, as well as a Holocene sea level rise model which combined with bathymetric data leads to an estimation of recent divergence time in populations of the Balearic lizards.

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New data on estimated divergence times of the populations of lacertid lizards in the Balearic Islands are provided in this second update of the October 2011 article: Estimating recent divergence time in populations of Podarcis lilfordi (GÜNTHER, 1874) and Podarcis pityusensis (BOSCÁ, 1883) (VAN DEN BERG 2011), which received its first update May 2012. In most cases better estimations of divergence times were available by using the NAVIONICS SonarCharts™webapp.

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More than three decades of fascination for the endemic Balearic sisterspecies Podarcis lilfordi (GÜNTHER, 1874) and Podarcis pityusensis (BOSCÁ, 1883), resulted in 30 trips (1980-2013) to the home of these lacertid lizards, in which we studied their ethology as well as their distribution and geographical differences in pattern and coloration. In comparison to prior scientific studies that led to an inflationary description of subspecies, we often found wide variations within populations and their subspecific characteristics. The question “To be distinct, or not to be distinct” is, to our opinion, not answered correctly in most cases. In order to gather data for a future revision of the present subspecific order, we started in 2011 to collect data of these lizards in a structured way, and storing this data in a free accessible database (www.pityusensis.nl). Later in 2011 we enhanced our dataset by gathering tissue samples of the lizards, using the non invasive technique of buccal swabbing, for future accompanied DNA research.

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Phylogenetic relationships and timings of major cladogenesis events are investigated in the Balearic Island lizards Podarcis lilfordi and Podarcis pityusensis using 2675 bp of mitochondrial and nuclear DNA sequences. Partitioned Bayesian and Maximum Parsimony analyses provided a well-resolved phylogeny with high node-support values. Bayesian MCMC estimation of node dates was investigated by comparing means of posterior distributions from different subsets of the sequence against the most robust analysis which used multiple partitions and allowed for rate heterogeneity among branches under a rate-drift model. Evolutionary rates were systematically underestimated and thus divergence times overestimated when sequences containing lower numbers of variable sites were used (based on ingroup node constraints). The following analyses allowed the best recovery of node times under the constant-rate (i.e., perfect clock) model: (i) all cytochrome b sequence (partitioned by codon position), (ii) cytochrome b (codon position 3 alone), (iii) NADH dehydrogenase (subunits 1 and 2; partitioned by codon position), (iv) cytochrome b and NADH dehydrogenase sequence together (six gene–codon partitions), (v) all unpartitioned sequence, (vi) a full multipartition analysis (nine partitions). Of these, only (iv) and (vi) performed well under the rate-drift model. These findings have significant implications for dating of recent divergence times in other taxa. The earliest P. lilfordi cladogenesis event (divergence of Menorcan populations), occurred before the end of the Pliocene, some 2.6 Ma. Subsequent events led to a West Mallorcan lineage (2.0 Ma ago), followed 1.2 Ma ago by divergence of populations from the southern part of the Cabrera archipelago from a widely-distributed group from north Cabrera, northern and southern Mallorcan islets. Divergence within P. pityusensis is more recent with the main Ibiza and Formentera clades sharing a common ancestor at about 1.0 Ma ago. Climatic and sea level changes are likely to have initiated cladogenesis, with lineages making secondary contact during periodic landbridge formation. This oscillating cross-archipelago pattern in which ancient divergence is followed by repeated contact resembles that seen between East-West refugia populations from mainland Europe.

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Many lizards use femoral gland secretions in intraspecific communication. Although there is a consistent interspecific variation in chemical composition of secretions, considerable variation is also often found between populations, which may affect conspecifc recognition and lead to speciation processes. Balearic lizards (Podarcis lilfordi) are currently distributed only in several isolated islets offshore of the main islands with different environmental conditions (vegetation, diet, density of population, etc). Also, there is a high genetic variability between populations. We examined whether there was a similar variation in the composition of the femoral secretions of male lizards, and which could be the causes of such variation. By using GC–MS analyses, we found 75 lipophilic compounds in femoral gland secretions of male P. lilfordi from three representative island populations. Main compounds were steroids (94.4%), mainly cholesterol, but we also found alkanes, ketones, waxy esters, squalene, carboxylic acids and their ethyl esters, alcohols and other minor compounds. However, there were clear differences between populations with respect to the number and relative proportions of compounds. Using the patterns of presence and abundance of compounds in secretions it is possible to predict the population of origin of a lizard. We discuss how these differences could be explained considering genetic and environmental differences between populations.

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Unique body characteristics are increasingly used for individual recognition to avoid the effort and the potential negative effects of capture–mark–recapture technique.As a consequence there is a growing demand for computer procedures to assist users in photo-recognition of an individual. We present a new software for photo-matching developed to minimize the pre-processing time and maximize the speed of the matching procedure. In APHIS photos can be processed in batches of hundreds and users can select between two alternative matching procedures, one interactive, built as an extension of existing and freely available software, and one automatic. We assessed its performance in terms of individual recognition and time efficiency and illustrate its use with real capture-photo–recapture studies on a reptile and an amphibian species, the Balearic Lizard Podiarcis lilfordi and the Northern spectacled salamander Salamandrina perspicillata, with contrasting skin patterns.

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Aims: To characterize the genetic and morphological diversification of the endan- gered Balearic lizard Podarcis lilfordi and to assess the relevance of this diversity, and how it is described, to conservation measures. Location: This study covers all the populations of the Balearic lizard, Podarcis lilfordi, present in its range of distribution at coastal islets of Menorca, Mallorca and Cabrera Archipelago. Methods: We analysed genetic and morphological variation across the 43 known extant populations of the Balearic lizard, using mitochondrial and nuclear markers. We examined morphometric and scalation characters using, in some cases, phyloge- netically independent contrasts. We also incorporated the study of dorsal coloration and dorsal colour pattern including the analysis of melanism in several populations. Results: We detected clear genetic divergence between Menorcan populations and populations from Mallorca and Cabrera, in both nuclear and mtDNA markers, but genetic divergence is relatively low among different insular populations within these groups. In contrast, morphological divergence was substantial both between Menorcan and remaining populations and within these groups. Morphological traits, such as dorsal coloration, body size and the number and size of scales, seemed to be linked with differences in climatic conditions between populations. In addition, some traits, as melanism, showed a strong phylogenetic signal. Main conclusions: The morphological and genetic diversity of the Balearic lizard is incongruent with the subspecies described in the classical taxonomic literature. Moreover, current populations differ not only in some genetic and morphological features, but also in several ecological and ethological characteristics, in many cases unique to one population. Based on our results, we propose abandoning the use of subspecies to describe the extraordinary morphological diversity of the Balearic liz- ard and its replacement with the concept of evolutionary significant units (ESUs). ESUs are particularly suitable to describe and recognize such diversity and, especially, to ensure the continuity of the evolutionary process.

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he Balearic lizard, Podarcis lilfordi, is present in 43 insular populations in the Cabrera archipelago and around the coasts of Mallorca and Menorca islands (Spain). We studied lizard densities over the entire range of distribution, analyzing observed differences of density in relation to island area, habitat diversity, availability of resources, presence of predators, competitors and human disturbances. The density of the Balearic lizard varies from less than 35 to almost 8000 lizards ha-1, with an average of around 1500 lizards ha-1. In some very small islets we detected no more than 10 individuals. Using a subsample of nine coastal islets (Menorca) we did not find any significant correlation between ground arthropod biomass and lizard density. The combination of island area and its maximal altitude, its so-called biotic capacity, was also uncorrelated with lizard density. In addition, neither degree of island accessibility nor presence/absence of seagull breeding colonies, were able to explain lizard densities. Islands without ship rats (Rattus rattus) showed a significantly higher lizard density, but islands in which rat eradication programs were launched during the study period, showed lower densities than those with rats but no eradication actions. Genetic variability was significantly higher on bigger lizard populations, lacking a correlation with lizard densities. No single independent variable can explain density differences among populations under study. Our results are discussed in the light of available hypotheses on factors affecting population densities.

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The Balearic lizard P. lilfordi inhabits the Gymnesies Islands and have sexual dimorphism. By means of biometric studies and analyses such as the discriminant analysis, it has been determined the morphometric characters that determine this sexual dimorphism. The characters chosen by the analysis were: body length, pileus width, number of gular scales, length of the four finger of the posterior leg. The differential measures of these characters makes the males to have a burlness and robustness greater than the females of the same population. Nevertheless, it cannot be said that in all P. lilfordi populations, the males will be aways the most burliness and robustness,but this will depend upon th population of P. lilfordi we take into consideration.

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Comparisons among eight populations of Podarcis lilfordi, seven of Podarcis pityusensis (representative lizards of the Balearic Archipielago), and one of Podarcis hispanica atrata fro the Columbretes Islands, have been made from a morphological point of view, measuring 15 morphometric characters of the lizards. Cluster and discriminant analyses were obtained for males and females to show the relationships among the different populations and species. These analyses gave three groups: one of them with the most P. lilfordi populations, other with the most P. pityusensis populations, and a well seperated group with the P. hispanica atrata species. Some populations connect the groups of P. lilfordi and P. pityusensis. The possibility that P. lilfordi and P. pityusensis be two pattern of variation inside the same species instead of two well differentiated species is considered, altrough further studies are necessary.

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The body growth rate in small reptiles is modulated by per-capita food resources and recent evidences suggested that this constraint is the mechanism underlying differences between cohorts. Per-capita food resources depend on population size and climatic factors but their relative role in explaining the variations in growth rate is unclear. We used morphological data collected over six years to model the body growth of an insular lizard (Podarcis lilfordi Günter, 1874). We used non-linear equations to describe the appropriate length-at-age relationship. For each sex, seasonal growth was observed and the oscillatory Von Bertalanffy curve was fitted to the data. Three age classes were recognized, and we investigated the relative role of density, spring rainfall and temperature in explaining the variation of the growth rate in each sex-by-age class. Results showed that the relative role of density and climatic factors varied according to the age considered. While population size and temperature had a negative effect in the growth rate of juveniles, rainfall had a positive influence for the growth of sub-adults. Adult growth was near zero and constant over time. The different role of density-dependent and climatic factors in explaining age-dependent growth rate provides an important insight in understanding lizard population dynamics and life-history tactics.

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Animal density, despite being conceptually simple, it is one of the most difficult parameter to measure in the field. We compared density estimates of a lizard, Podarcis lilfordi derived by line transects with those from a simultaneous capture–recapture study in three islands of the Balearic archipelago (Spain). The two methods delivered similar results but have different pitfalls and advantages. Line-transects provided a fast and economic method, but density estimates changed over space and time. On the other hand capture-recapture techniques were time consuming, but estimates were similar over the sampling days and showed lower variances.

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Estimating population size and understanding its variation is a fundamental, yet complicated, aim of many ecological studies. We considered the problem of estimating spring and autumn population abundance, size-dependent population structure and sex-ratio of the endemic Balearic Lizard, Podarcis lilfordi from a three occasions capture-recapture study. We used a Bayesian formulation of individual covariate models to incorporate individual sex, size and trap-response. We first considered a set of simulated data with a medium-to-low probability of recapture and individual recapture heterogeneity to evaluate potential problems in model fitting and selection. Results from simulated data indicated a low performance in parameter estimation and model selection when probability of detection was low (0.15-0.30). We found a negative permanent trap response and a positive effect of size on detection probability in the spring survey but not in the autumn one. The estimated mean densities varied from about 800 to 1000 lizards ha(-1), a high value when comparing with mainland lizard populations. The observed increase in abundance was probably due to a drop in territorial behaviour and the immigration of females into the area sampled. As a consequence, sex-ratio changed from nearly even in June (mean posterior, 95%CRI; 0.928, 0.676-1.167) to a female-skewed population in October (0.612, 0.478-0.772).

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Aim To describe and analyse phylogeographical patterns in the endangered endemic lizard Podarcis lilfordi from across its remaining range and thereby establish baseline information on genetic diversity that will help determine conservation priorities and assist future reintroduction programs. Location Balearic Islands, Spain. Methods We analysed mitochondrial DNA (2382 bp sequence from eight genes) from 118 individuals and characterized the relationships among haplotypes using parsimony networks, as well as phylogenetic inference. Analyses of historical gene flow and population growth were used to provide further insights into population histories. Results Four unconnected parsimony networks were obtained that mirrored the main clades in the phylogenetic tree: (I) all Menorcan populations, (II) Dragonera, Malgrats and Toro islands (Western Mallorca) (III and IV) and the remaining populations from Cabrera and Mallorca. Two major haplotype groups were detected in Menorca (I) and these provided signatures of a demographic expansion and asymmetrical historical gene flow, respectively, concordant with the expected direction of colonization from south to north of the island. Populations from western Mallorca (II) showed evidence of historical allopatric fragmentation events following isolation around the start of the Pleistocene. In networks III and IV, Cabreran populations appear to have become isolated from north and south Mallorca quite recently, with asymmetric gene flow indicating a northwards dispersal direction. Main conclusions P. lilfordi is a genetically diverse species that shows substantial mtDNA structuring both between regions and, at a finer scale, between some islet populations within regions. The precarious state of some islet populations shown here to be quite divergent (e.g. Toro island in western Mallorca) means that conservation of this intraspecific biodiversity requires urgent action.