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Dietary studies are essential to unravel the functioning of ecosystems and ultimately to understand biodiversity. This task, which at first may seem simple, becomes especially complex in those cases of omnivorous species with highly variable diets. In this regard, the emergence of next-generation DNA sequencing methodologies represents a powerful tool to address the problem. Here we implement a high-throughput metabarcoding strategy based on the analysis of four molecular markers aimed at sequencing both mitochondrial (animal prey) and chloroplast (diet plants) genome fragments from fecal samples of two lizard species endemic to the Balearic Archipelago (Podarcis lilfordi and P. pityusensis) obtained through non-invasive methods. The results allowed for the characterization of their diets with a high degree of taxonomic detail and have contributed a large number of new trophic records. The reported diets are based mainly on the consumption of arthropods, mollusks and plants from a diversity of taxonomic orders, as well as carrion and marine subsidies. Our analyses also reveal inter- and intra-specific differences both in terms of seasonality and geographical distribution of the sampled lizard populations. These molecular findings provide new insights into the trophic interactions of these threatened endemic lizards in their unique and isolated ecosystems.

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Gut microbial communities provide essential functions to their hosts and are known to influence both their ecology and evolution. However, our knowledge of these complex associations is still very limited in reptiles. Here we report the 16S rRNA gene faecal microbiota profiles of two lizard species endemic to the Balearic archipelago (Podarcis lilfordi and P. pityusensis), encompassing their allopatric range of distribution through a noninvasive sampling, as an alternative to previ- ous studies that implied killing specimens of these IUCN endangered and near-threatened species, respectively. Both lizard species showed a faecal microbiome composition consistent with their omnivorous trophic ecology, with a high representa- tion of cellulolytic bacteria taxa. We also identified species-specific core microbiota signatures and retrieved lizard species, islet ascription, and seasonality as the main factors in explaining bacterial community composition. The different Balearic Podarcis populations are characterised by harbouring a high proportion of unique bacterial taxa, thus reinforcing their view as unique and divergent evolutionary entities.

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A complete catalogue is provided for the type specimens of lacertid lizards in the herpetological collection of the Zoological Museum, Berlin, as of December, 1993. The collection contains a total of 514 type specimens, representing 63 taxa, of which 42 are currently regarded as valid at the specific or subspecific level. Types representing an additional four taxa appear to have been lost from the collection. The collections are especially rich in African lacertid types and in historically significant specimens collected early in the Nineteenth Century by Pallas, Eversmann, and Hemprich & Ehrenberg. Also present are the type series of many subspecies of Podarcis lilfordi and P. pityusensis described by Eisentraut.

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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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This is already our sixth report in a series on our whereabouts while collecting data for a future revision of the present subspecific order of the endemic Balearic sisterspecies Podarcis lilfordi (GÜNTHER, 1874) and Podarcis pityusensis (BOSCÁ, 1883), which data are stored in our database at www.pityusensis.nl (VAN DEN BERG & ZAWADZKI 2011 ; VAN DEN BERG et al. 2013 ; VAN DEN BERG et al. 2014a ; VAN DEN BERG et al. 2014b ; VAN DEN BERG et al. 2015). During this trip from the 27th of March until the 9th of April 2016, we were able to collect data at some mainland Ibiza locations, as well as on the following adjacent islands: Sa Mesquida, S’Hort, S’Illeta de Cala Salada, Vedranell, Rates, Bleda Plana, Murada, Bleda Na Bosc and S’Espardell de S’Espartar. We continue with the ventral coloration as a possible determining key as introduced in our 2014 trip report (VAN DEN BERG et al. 2014b). Images of the anal shields are presented of each lizard for purposes of illustration.

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Es wird über einen 1930 angesetzten Versuch berichtet, bei dem auf einem bis dahin eidechsenfreien Felseiland (Dado Grande bei Ibiza, Pityusen) Männchen einer melanistischen und Weibchen einer grünen Inselpopulation von Podarcis pityusensis ausgesetzt wurden. Die Untersuchung von sechs fünf Jahre später gefangenen Tieren ergibt, dass die Vermischung zu erhöhter Variabilität und gesteigertem Größenwuchs geführt hat. Eine erneute Kontrolle dieses noch vorläufigen Ergebnisses wird angeregt.

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EL ESTUDIO ABORDADO EN LA TESIS VERSA SOBRE LA CARACTERIZACION TAXONOMICA DE LA LAGARTIJA DE LAS PITIUSAS PODARCIS PITVUSENSIS. SE ANALIZAN LAS DISTINTAS POBLACIONES DESDE TRES ASPECTOS DISTINTOS: EL ANALISISBIOMETRICO EL ANALISIS ELECTROFORETICO DE DISTINTAS PROTEINAS Y EL ANALISIS COLORIMETRICO. LOS ANALISIS ESTADISTICOS APLICADOS SOBRE LAS VARIANTES BIOMETRICAS DEMUESTRAN LA EXISTENCIA DE DIVERSOS GRUPOS DE POBLACIONES MUY SEMEJANTES ENTRE SI. LA VARIABILIDAD DE LA ESPECIE NO SOLO ES FENOTIPICA SINO QUE TAMBIEN ES GENETICA DETECTANDOSE UNA DIVERSIDAD EN ESTOS CARACTERES SUPERIOR A LA ESPERADA EN REPTILES. SE OBSERVA UNA ALTA HETEROSIS QUE ES CARACTERISTICA DE LA ESPECIE LO QUE PARECE DEMOSTRAR QUE ESTA SE ENCUENTRA EN LAS PRIMERAS FASES DE COLONIZACIONY ADAPTACION A LOS DIFERENTES HABITATS OFRECEN LAS ISLAS QUE OCUPA. SE CONSTATA LA ACCION DEL EFECTO FUNDADOR Y LA DERIVA GENETICA EN LOS TRES ASPECTOS CONSIDERADOS EN LA TESIS ASI COMO UNA TENDENCIA EVOLUTIVA HACIA EL AUMENTO DE TAMAÑO SIEMPRE QUE NO EXISTA UNA PRESION SELECTIVA CONTRARIA. SUCEDE LO MISMO CON EL MELANISMO. CONSIDERANDO EL ESTADO EVOLUTIVO ACTUAL DE LA ESPECIE REFLEJADO EN LA PLASTICIDAD DE LAS DISTINTAS POBLACIONES DE ESTALAARTIJA Y EN LA ADAPTACION QUE MANIFIESTAN EN CADA NICHO CONCRETO ASI COMO EL CONCEPTO RESTRICTIVO ACTUAL DE SUBESPECIE LA AUTORA CONSIDERA QUE SOLO PUEDEN CONSIDERARSE SEIS TAXONES SUBESPECIFICOS O SUBESPECIES DE LA LAGARTIJA DE LAS PITIUSAS.

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In this paper are presented the results obtained with 45 populations of Podarcis pityusensis. Several multivariant technics are performed: discriminant analysis, cluster analysis and canonic analysis of populations. These populations present gradual change in all their biometric characteristics, and also a great interpopulation variability, that invalidate th statistical methods to discriminate between all of them. In different analysis very related population groups are found, that suggests they are constitute the same subspecies, in the actual taxonomic sense. These groups always inhabits islands with the same geological age, it is therefore necessary to complete the study with othr biological reflections, all of which are getting ready.

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The variation in morphological and colouring features shown by the insular lacertid populations of Podarcis pityusensis is discussed from the point of view of their adaptive advantages to specific insular ecosystems. Insularity factors, i.e. area and island-age, have been found to be related to average body size, and the average luminosity of each population. Populations tend to show a size increase, a greater morphological homogeneity and darker dorsal colouring on smaller and older islands. Genetic drift seems to play a secondary role, whereas a positive selection in favour of melanism and giantism is observed. Both features are not linked as cause and effect, but seem to share a common cause: isolation and time enough to allow selection to take place. Predation, though slight in degree, does exist, and seems to be one of the selective pressure favouring melanism, together with the parallel trend towards an increase in body size and the need to an effective thermoregulation during the early hours of the day.

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The Ibiza wall lizard is the symbol of the Pityusic-Archipelago, but what makes this colorful reptile so special? The Symbol: wall lizards of Ibiza and Formentera will take you on a journey into the culture, biology, ecology, and conservation of Ibiza and Formentera’s most iconic animal.

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Comparative analyses were carried out about the variability of the pileal shields of different species belonging to the family Lacertidae. The results of the comparisons have been evaluated in respect to the phylogenetical relationships existing between the different genera and species of the family.

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The status of the populations of Podarcis pityusensis on about 70 islets and small islands around Ibiza and Formentera (Balearic Islands) is examined, using data from our own observations, and, to a lesser amount, other publications. Lizard populations were found on 43 islets, but data are lacking for another 13. Only 10 sites (18 %) have abundant and well-maintained populations. In 13 localities (23%), there is no geographic isolation between the populations, or this isolation is very poor and incomplete. The high probability of populations mixing, or actual observation of this mixing, in 19 islands (34%) is indicated. Human pressure on lizard populations is strong in 14 cases (25 %). And finally, 18 populations (about one third) may be considered highly endangered or already extinct by elimination or genetic mixing with other populations. Among the subspecies which became extinct through mixing are P.p. miguelensis, P.p. subformenterae, P.p. algae, P.p. sabinae and P.p. grueni. The need for adequate protective measures aimed at the conservation of the remaining populations is emphasized.

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The Ibizan wall lizard, Podarcis pityusensis, was the subject of several documented translocations by the German vertebrate zoologist Martin Eisentraut, in 1930. He aimed to initiate long-term experiments into the evolution of melanism and other morphological traits and accordingly he designed introductions into five islets that (he believed) contained no lizards. In this study, we analyzed the genetic and morphological characteristics of individuals we found there. We found no lizards on two of the islets, namely Escull de Tramuntana and Galera, but for the first time, detected a large population on a third islet, Es Vaixell. Eisentraut founded the Es Vaixell population with nonmelanistic Ibizan specimens, but the present day population of Es Vaixell was found to be fully melanistic. Genetic markers support a strong similarity between Es Vaixell and its neighbour islet, Na Gorra, and indicate that, in all likelihood, the individuals introduced by Eisentraut have left no descendants. It is likely that Es Vaixell already contained lizards prior to this introduction. Analyses of microsatellite DNA placed individuals from a fourth islet, Dau Gran, with those of one of its source islet, Escull Vermell. They are also morphologically close to individuals from Escull Vermell. This suggests that selection pressures could have favoured the Escull Vermell phenotype following introduction. For reasons we discuss, the translocations have revealed less than Eisentraut would have originally hoped for. Although evolutionary processes are normally time-consuming, these translocations do provide some potential insights into the rapid evolution of lizard morphology following colonization.

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Two monophyletic sister species of wall lizards inhabit the two main groups of Balearic Islands: Podarcis lilfordi from islets and small islands around Mallorca and Menorca and Podarcis pityusensis from Ibiza, Formentera and associated islets. Genetic diversity within the endangered P. lilfordi has been well characterized, but P. pityusensis has not been studied in depth. Here, 2430 bp of mtDNA and 15 microsatellite loci were analysed from P. pityusensis populations from across its natural range. Two main genetic groupings were identified, although geographical structuring differed slightly between the mtDNA and the nuclear loci. In general, individuals from islets/islands adjacent to the main island of Ibiza were genetically distinct from those from Formentera and the associated Freus islands for both mtDNA and the nuclear loci. However, most individuals from the island of Ibiza were grouped with neighbouring islets/islands for nuclear loci, but with Formentera and Freus islands for the mitochondrial locus. A time-calibrated Bayesian tree was constructed for the principal mitochondrial lineages within the Balearics, using the multispecies coalescent model, and provided statistical support for divergence of the two main P. pityusensis lineages 0.111–0.295 Ma. This suggests a mid-late Pleistocene intraspecific divergence, compared with an early Pleistocene divergence in P. lilfordi, and postdates some major increases in sea level between 0.4 and 0.6 Ma, which may have flooded Formentera. The program IMa2 provided a posterior divergence time of 0.089–0.221 Ma, which was similar to the multispecies coalescent tree estimate. More significantly, it indicated low but asymmetric effective gene copy migration rates, with higher migration from Formentera to Ibiza populations. Our findings suggest that much of the present-day diversity may have originated from a late Pleistocene colonization of one island group from the other, followed by allopatric divergence of these populations. Subsequent gene flow between these insular groups seems likely to be explained by recent human introductions. Two evolutionary significant units can be defined for P. pityusensis but these units would need to exclude the populations that have been the subjects of recent admixture.

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There is a census of groups of lizards in some of the small islands of the Balearics, obtained by method of simplified successive suppression. The results are coherent with the observations in 50% of the cases. The minimum known group is of 6 ex. in the small islet of Fornol (Cabrera). The highest density corresponds to Escull Vermell in the group of Ses Bledes in Ibiza with 50 ex. in 350 m2 (1428 ex/Ha).

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Survey of the present known occurrences of population exposures within the Ibiza wall lizard (Podarcis pityusensis Boscà,1883). Probably more often than it has been documented in the past, lizards are transported with the help of men to other islands or islets where either no lizards live or which are inhabited by different subspecies. Therefore the mixing of populations is possible and the genetic barrier is broken which leads to complications in the taxonomy of these species. In some cases unfortunately such transported lizards have probably been described as different subspecies. In the future taxonomic studies of this specie the possible precence of such transported lizards within various populations should be given more attention.

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A brief report on the longevity in captivity of Podarcis pityusensis and Podarcis lilfordi.

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Some subspecies of the endemie Ibiza wall lizard Podarcis pityusensis (BoscA, 1883) were observed in their natural environment and are briefly described with some complementary notes on their population density.

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During several visits to th island Illiot de Sa Mesquida (Mesquida) the lizard Podarcis pityusensis pityusensis (Boscá 1883) was found in variable numbers Presumed is that the fluctuation within the lizard population is affected by the nesting colony of gulls (Larus cachinnans).