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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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Some remarks are made about the variability in Podarcis pityusensis in the Formentera and adjacent island populations. Two new islet populations of this species are described for Illa de Ses Perreres and Illa d’es Fonoll Mori, close to Es Pujols (Formentera).

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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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The Ibiza wall lizard Podarcis pityusensis (Boscá, 1883) is the only living endemic land vertebrate of the Pityusic Islands. It has not only become the symbol of these islands, but also plays a significant role in the sub-archipelago’s ecosystem. For centuries, Ibiza was famous for being completely free of snakes. Unfortunately, this is no longer the case. The introduction of three snake species on Ibiza has changed the natural balance of the island. The horseshoe whip snake Hemorrhois hippocrepis is of particular concern as it is threatening to wipe out the native lizards. Not only does Podarcis pityusensis disappear at a worrying rate on Ibiza: the population from the little offshore island Illot de S’Oro, representing the subspecies Podarcis pityusensis hortae, has already become extinct due to this new predator.

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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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This is our fifth 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 free accessible 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). During this trip from the 9th of May until the 23rd of May 2015, we were able to collect data on a few mainland Ibiza locations, as well as the following adjacent islands: Punta Galera, Es Canaret, Illa de la Xanga (Sal Rossa), Pouet de Ses Illetes, Formentera, Purroig, Es Vedrà, Rates, Malví Pla (North), Malví Rodó (South), S’Espardell, Calders, Penjats and Ses Margalides. 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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A short introduction and a hypothetical model concerning color formation in lacertid lizards is presented. Thereafter we observe and discus the ontogenetic changes in a single female captive bred Podarcis pityusensis lizard from Formentera (Balearic islands/Spain). Striking transformations concerning coloration are observed.

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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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The association between polymorphism at the mc1r locus and colour variation was studied in two wall lizard species (Podarcis lilfordi and P. pityusensis) from the Balearic archipelago. Podarcis lilfordi comprises several deep mitochondrial lineages, the oldest of which originated in the Pliocene, while much shallower mitochondrial lineages are found in P. pityusensis. Here, we examined whether specific substitutions were associated with the melanic colouration found in islet populations of these species. Homologous nuclear sequences covering most of the mc1r gene were obtained from 73 individuals from melanic and non-melanic Podarcis from different populations (the entire gene was also sequenced in six selected individuals). MtDNA gene trees were also constructed and used as a framework to assess mc1r diversity. Mc1r showed greater polymorphism in P. lilfordi than in P. pityusensis. However, we observed no substitutions that were common to all melanic individuals across the two species. Only one significant association was detected in the mc1r partial sequence, but this was a synonymous A/G mutation with A alleles being more abundant in melanic populations. In addition, there were no associations between the main dominant phenotypes (green and brown, blue and yellow spots and ventral colour) and synonymous or non-synonymous substitutions in the mc1r gene. There was no statistical evidence of selection on mc1r. This study suggests no relationship between mc1r polymorphism and colour variation in Balearic Podarcis.

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We review the enormous photographic material obtained from the 80`s of the 20th century to the present and the descriptions of body colouration of the many consulted collections of Podarcis pityusensisfrom the island of Formentera. The wide variety of colourations is evident, with a large intra-population and inter-population polymorphism existing on the island of Formentera. A north-south gradual change is observed, especially at the Punta des Trucadors, parallel to the changes in the substrate and the vegetation. It is also noted that not all the colors of Podarcis pityusensis formenteraeare present in all parts of the island, but that each region has its own colourations, and always with a high intra-population richness.Comparing the material obtained at different periods, it can be seen that the geographic differences in lizard body colouration persist over time.The offspring always have the same colouration throughout the island.

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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 dorsal, side and belly colours of 118 specimens of Podarcis pityusensis have been analysed with physical methods. Twenty samples from 16 islands have been chosen, 3 of then from Eivissa Island (Ibiza), 2 from Formentera Island and 2 from Espardell Island. The results reveal great colouration differences between the same island samples and sometimes similar colouration between different islands (different subspecies). specimens. This feature seems to show the colour criteria is not useful in taxonomic subjects for this species.

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Hemorrhois hippocrepis arrives at the beginning of the twenty-first century to the Pityusic Islands, like an invasive species and it has placed the endemic lizard Podarcis pityusensis at serious risk of extinction in the two major islands. It makes urgent to have an estimated population density of lizards in the various islets of the Pityusas. It has been used personal field notes with the indications that allow us to estimate the population density in the different visits realized to the islets from 1979 to 2024.

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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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In many species, secondary sexual characters increase male fitness, yet the same traits can be detrimental when expressed in females due to differences in selective pressures between the sexes. This sexually antagonistic selection may drive intralocus sexual conflict (ISC), in which genes that are beneficial when expressed in one sex are detrimental when expressed in the other. ISC is thought to drive the evolution of sexual dimorphism in these traits through the decoupling of the trait’s expression between the sexes. Nevertheless, in many species male-typical secondary sex traits are partially or fully expressed in females, and few studies have investigated the significance of such traits in natural populations. In the context of ISC, the present study investigates the significance of a male-typical secondary sexual character (conspicuous coloration) in a free-living female Ibiza Wall Lizards, Podarcis pityusensis, a species expressing striking color-diversity across its range and between the sexes. By manipulating lizard color, monitoring the effects of this manipulation on individuals’ behavior and reproductive success throughout the reproductive season, and measuring the heritability of color from parents to same and opposite-sex offspring, this study identifies sexually antagonistic selection which drived ISC over color expression in male and female lizards.

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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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We provide a fi rst complete list of the present and lost reptile type material of the Zoologische Staatssammlung München (ZSM) and discuss various problems involved. The collection currently houses primary types of 184 taxa (128 holotypes, 44 lectotypes, and 12 taxa based on syntype series), 112 of them currently considered valid. Furthermore, 63 taxa are exclusively represented by secondary types (paratypes, paralectotypes). The ZSM collection strongly suffered from losses during World War II. Approximately 90 primary reptile type specimens or primary type series are considered to be destroyed during that time. The historical focus of the collection is the South American region. This is primarily based on material collected by Spix and Martius during their expedition to Brazil from 1817 to 1820. Primary types of 83 reptile taxa were collected during this expedition – approximately half of them described by J. G. Wagler – but currently specimens of only 53 taxa are still present in Munich. Subsequently, herpetological research in South America was continued during the fi rst half of the 20th Century by L. Müller und W. Hellmich, who deposited primary type material of 95 reptile taxa (49 from South America, among them 26 of the iguanid genus Liolaemus) in the ZSM, 47 of them still represented by primary types. Another geographical focus of the reptile type collection is the Mediterranean area, the Macaronesian region and the Middle East with a total of 46 extant primary types. Herpetological research in this area dates back to descriptions by G. Jan in 1863 and was continued by L. Müller, H. H. Schleich, A. Beutler, and especially J. F. Schmidtler and their respective collaborators.

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An electrophoretic comparison of ten colonies of Podarcis pityusensis Bosca, 1882 (Lacertidae) from Ibiza, Formentera and neighbouring islets (Balearic Is., Spain). 71 animals from ten colonies (vide list in text) of the Ibiza wall lizard Podarcis pi- tyusensis Bosca, 1882 were analysed by electrophoresis, on 12 % starch gel, and 16 gene- tic loci were studied, by checking against samples of Podarcis muralis muralis. The genetic frequency resulting in NEI`s identity index (I), reveals no clear differen- ces between the various colonies. However, itcan be seen on the resultant dendogram that P. p. carlkochi (affinis group) is distinct from the pityusensis sensu stricto group colonies. By other means we found characteristic allels for Podarcis pityusensis in four loci: GOT-1, IDM-1, G-6-PD-2 and 6-PGD, which differed from Podarcis muralis allels.

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At the end of November, Podarcis pityusensis could be observed on Ibiza and Formentera only at places protected from the wind, when the sun was shining and the air warmed up to 20 to 25°C.

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546 lizards of different geographically isolated populations of the specus Lacerta pityusensis were studied using an systematic criteria correlative and allometric changes of body proportions, coloration and pattern. Some other criteria often used in systematic studies on southern European lizards were unsuitable, since they do not differ significantly between the populations. With the exception of the Trocados (Trocardors) lizard (L. p. grueni) all adults of the populations on the seperate offshore islands increase their body size, in particular L. p. grossae on St. Eulalia (Illa de Santa Eulalia) and L. p. maluquerorum on Bleda Nebosque Island (Na Bosc). The studies on correlative and allometric changes of body proportions showed: All criteria show a marked sexual dimorphism, the males are larger and have longer pilei and hindlimbs. The allometric changes in length of pileus / width of pileus were found to be possitive in males however negativ in females in all populations except the N-Formentera lizards. The females of the geographically isolated populations differ more between each other and in comparison with Ibiza females than do males. Lizards of the island populations have more slender pilei than Ibiza lizards. The females have longer hindlimbs but in some populations the hindlimbs of the males show a more negative allometric growth. Smaller adult males of these populations have longer while larger males have shorter hindlimbs than the Ibiza lizards. The studies of coloration and pattern showed that in particular the populations of the east coast of Ibiza differ from those given in other studies. In the population of L. p. grossae on St. Eulalia (Illa de Santa Eulalia) grey green individuals without a red belly are found, in the population of L. p. canensis on Es Cana Island (Caná) are some light green lizards. The females of L. p. redonae (Redonda de Santa Eulalia) and L. p. canensis (Caná) were described the first time. The population on east coast islands show no tendency to darker coloration. The populations longest isolated display the most brightest colours. L. p. grueni inhabits the peninsula (not island) Trocados (Trocadors). This subspecies is distributed over the extreme north of Formentera and in the south of it`s range hybridisation with the subspecies L. p. formenterae occurs. The lizards of playa La Sabina, N-Formentera and some related offshore islands are with regard to all criteria intermediate to the lizards of Ibiza and the remaining Formentera. The subspecies L. p. algae (Pouet), subformenterae (Conejo de Formentera) and sabinae (Sabina), described from that region, are considered as synoyms of L. p. pityusensis as well as L. p. formenterae. Since the lizards of the Islas de Purroige (Ses Illetes de Purroig) differ hardly from the lizards of Ibiza, this subspecies (L. p. purroigensis) is considered a synonym of L. p. pityusensis. Lacerta p. zenonis from the tiny island Escui de Esparto (Escull de S`Espartar) probably does not differ from L. p. kameriana from the island of Esparto (Espartar). In future, the ecology, structure and size of the isolated lizard populations shall be studied and compared. It is suggested that the single island represent different eco-systems. An analysis shall be done on those parameters which maintain natural selection and are thus most imortant for the evolution of the lizards. It is considered that the social behaviour is of relevance to population dispersion and density and the regulation of population size.

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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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Understanding the evolution of conspicuous colour patterns has been a major challenge in evolutionary biology since darwin’s formulation of naztural and sexual selection 150 years ago. A striking case of conspicuous colouration is the structural blue colour found in lizards belonging to several families, including lacertids (Lacertidae). Blue colouration can be restricted to discrete patches, as those found in the flanks or head of many lacertids, or can extend over large areas of the integument as in several insular populations of Lacertini. Recent research has shown that the blue flank and head patches of many lavcertids have their peak of reflectance in the ultravolet (UV) range. It has been suggestes that these UV-blue patches may be part of a private (i.e. available only to receptors with UV vision) communication system. In contrast, nothing is known about the spectral characteristics of those species in which all or large portions of the body surface are blue. Using objective methods of colour measurement and analysis, we studies the spectral characteristics of blue colouration in Podarcis lilfordi kuligae and compared them with those from other blue lacertids. The ventral surface and flank patches of P. lilfordi kuligae are both UV-blue, but their spectral shape is strikingly different, possibly reflecting different underlying selewctive pressures and colour production mechanisms. To our knowledge, this is the first recorded case of polychromatism in the UV part of the electromagnetic spectrum. Our results show that a wide range of spectrally different colouration belie human-perceived blues in lacertids. We analyse visual interactions among lacertid colours and habitat natural backgrounds and propose some hypothesis for the evolution of lizard blue and UV-blue colouration.

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We examined the diets of several species of Podarcis from different western Mediterranean islands. We tested the prediction of more generalized diets in lizards from poor environments. We also examined the extert and mode of herbivory in relation to arthropod diversity in the diet. Lizards from the Tuscan Archipelago, P. sicula from Menorca, and P. tiliguerta from Corsica all show a rather generalized diet. In contrast, P. lilfordi and P. pilyusensis from the Balearic Islands and, to a lesser extent, P. hispanica from Benidorm Island, appear much more stenophagous, including a high proportion of clumped prey in their diets. Plant matter is a common food item in most of the population studied, specially in Balearic lizards. A marked seasonal shift in the degree of herbivory was observed in these species where high-energy plant parts are frequently consumed during summer. In one of the Balearic Islands (Nitge), the bulk of the summer diet was formed by pollen and nectar of one particular plant species. Herbivory, consumption of clumped prey and other dietary peculiarities of insular populations of Mediterranean lizards indicate a very flexible feeding behaviour compared to mainland congenerics. This could result from a lack of predation pressure allowing high population densities to be reached in islets with poor trophic resources. Differences found in dietary characteristics among island populations can be interpreted as a consequence of different current ecological conditions, as well as historical and biogeographical differences among the islands.

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While the use of faecal pellets is widely accepted as a primary methodological source of data for dietary studies, a recent paper advocated for the use of gut contents. This was due to the fact that faecal samples would give biased results of the diet of arthropod predators, due to a lower representation of soft-bodied prey in faecal pellets. To test this assumption, we compared the spring diet of several populations of two insular lizards from the Balearic Islands (Spain), Podarcis lilfordi and Podarcis pityusensis, using both faecal pellets and gut contents. Our results do not support the supposed bias of dietary analyses based on faecal pellets. Indeed, soft-bodied prey and particularly insect larvae are often equally represented in faecal pellets and gut contents. Alternatively, soft bodied prey are represented in different proportions in gut contents and faecal pellets, but in some cases with higher proportions being observed in the gut contents, and in other cases with higher proportions in faecal samples. We conclude that faecal pellets can be a reliable source of information for dietary studies.

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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 parasitic female of the nematode Strongyloides ophiusensis sp. n.. fund in the intestine of lizard Podarcis pityusensis (Bosca, 1883) from Balearic Islands (West Mediterranean), is described. This species differs from other similar Strongyloides species in the body size, the morphology of the stoma, the structure of the ovaries and in the stage of development of the eggs, and also in some ecological and chorological characters.

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The knowledge of the helminth communities of reptiles and their ecological relationships with their hosts are until the present not well known. Some general researches have been made only on American herps (AHO 1990). Recently, ROCA & HORNERO (1991a, 1991b) attempted similar kind of researches from Mediter- ranean insularlizards.

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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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A number of the subspecies were studied over several visits to Formentera and Ibiza. Podarcis pityusensis pityusensis is found on Ibiza. However, several animals of different colours were found not all of which conformed to the for that island described subspecies. Furthermore, on Formentera different forms of Podarcis pityusensis formenterae were observed. Three hybrids resulting from a cross between a male Podarcis lilfordi giglioli (Sa Dragonera) and a female Podarcis pityusensis formenterae were born under terrarium conditions. These hybrids proved to be fertile, after mating with Podarcis lilfordi lilfordi (Illa de l`Aire) males these three females laid 12 eggs. Due to a number of circumstances only one egg hatched but a normal young was produced. The various forms of Podarcis pityusensis are found not only on small islets but also on the main islands. Their presence seems to be dependent on the substrate. The hybrids and the various forms of Podarcis pityusensis on the main islands makes it questionable whether the classification of these animals into a great number of subspecies, or even into two species, is justified.

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Sequences of the cytochrome b gene were analysed for 47 samples of two species of Podarcis from the Balearic Islands (P. pityusensis from Pityuses and P. lilfordi, from Gymnesies archipelago). The average uncorrected distance between the two species studied was 9.7%. The sampled individuals from each species form reciprocally monophyletic units. Assuming an overall rate of change for cytochrome b of 2% per million years the nucleotide divergence of 9.7 ± 1.9% between P. lilfordi and P. pityusensis, could correspond to a divergence time of 4.95 ± 0.95 million years. The separation time between Gymnesies and Pityuses archipelagos according to geological hypotheses is around 5 million years, thus our results suggest the ancestors of the two present forms became isolated during this event. The most parsimonious networks suggest that currently accepted subspecies do not form monophyletic groups, and so should be reassessed. Despite our limited sampling the level of variability is much higher in P. lilfordi than P. pityusensis. Since they are sister taxa the relative age of each species is equal, therefore the differences might be due to historical population structure differences. However it seems that the forms on the islands are not genetically distinct units, implying that morphological differences are recent adaptations to their environments.

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The alteration of a habitat such as that caused by the introduction of exotic animal species that displace the native ones, reducing their populations or leading them to extinction, can result in the disruption of species interactions which may have evolved during millions of years. The insular ecosystems are especially vulnerable to such disturbances, as they are usually less complex and have a lower number of species than the continental ones. In the present work I document the consequences of the disruption of plant-disperser interactions, caused by the introduction of carnivorous mammals in the Balearic Islands, for the populations of two shrub species: Cneorum tricoccon L., with a distribution restricted to the western Mediterranean, and Daphne rodriguezii Texidor, endemic from Menorca island. Whereas carnivores have replaced ⁄ the native dispersers (lizards) of the former, notably modifying its distribution -especially in Mallorca-, the plant-lizard mutualism disruption seems to have been dramatic for the second species, drastically reducing its populations except in an islet where lizards still persist.

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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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Es wird kurz über Beobachtungen ungewöhnlicher Nahrung von Podarcis pityusensis formenterae am Cap de Barbaria im Süden Formenteras berichtet.

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The Ibiza wall lizard, Podarcis pityusensis is the only endemic land vertebrate of the Pityusic Islands. It inhabits the two main islands Ibiza and Formentera as well as the vast majority of the offshore small islands. When humans first arrived at the islands, they brought with them a handful of foreign predators, such as genets, beech martens, rats, and feral cats – all lizard predators. Podarcis pityusensis is fully protected by national and international legislation and listed in Annex II of the Bern Convention and in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora). It is declared as “Near Threatened” by the IUCN (2009). However, some of the populations are very much reduced, endangered or on the verge of extinction as they are threatened by illegal collection, disturbance by visitors, introduction of cats and rats to the islands, and accidental poisoning with bait left for seagulls. The recent introductions of three snake species on Ibiza and Formentera are of particular concern. The Montpellier snake (Malpolon monspessulanus) has not been caught on the islands since 2010. The horseshoe whip snake (Hemorrhois hippocrepis) has shifted its diet towards lizards, with the native Ibiza wall lizard, representing 55.4 % of the observed prey. A similar dietary shift is probably occurring with the ladder snake (Rhinechis scalaris) in Formentera, as a preliminary study shows that more than half of its prey is constituted by Podarcis pityusensis (HINCKLEY et al. 2017). The effect of predation may seriously threaten the lizards in the main islands and the arrival of snakes in the surrounding islands may produce a catastrophic and irrecoverable event for lizard populations as they would be the only available prey.

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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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Two cases of an unusual prey of Podarcis pityusensis are described. On 18.05.2011 on Punta Trucadors, the most northern Part of Formentera, a male Podarcis pityusensis formenterae was observed eating a lizard’s tail. It is possible that the tail found and eaten by the lizard was the lizard’s own tail that beforehand might got lost during an intraspecific fight. On 0.3.05.2013 near San Rafael, Ibiza, a male Podarcis pityusensis pityusensis tried to swallow a dead juvenile Tarentola mauritanica. Obviously the prey was too big and the lizard only managed to bite off and eat the gecko’s tail and right foreleg.