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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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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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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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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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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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The invasive snake Hemorrhois hippocrepis colonized the island of Ibiza (Balearic Islands) in 2003 as stowaways inside trunks of olive trees imported for gardening. It has quickly spread since 2010, posing a threat to the island’s only remaining endemic vertebrate, the Ibiza wall lizard Podarcis pityusensis. We map the yearly expansion rate of the snake and estimate via transect surveys how severely it affects the distribution and abundance of the endemic lizard. As well, we surveyed nine of 30 small lizard populations on islets surrounding Ibiza that have been isolated since the Last Glacial Maximum. Snakes had invaded 49% of Ibiza’s land area by 2018, and censuses show a critical contrast in lizard abundance between areas with and without snakes; almost all censuses in areas without snakes show lizard presence whereas nearly all censuses in areas with H. hippocrepis lack lizard sightings. Moreover, at least one subspecies previously thriving on one of the offshore islets has become extinct, and there have been several snakes recorded swimming between Ibiza and the surrounding islets. Therefore, lizard populations have been dramatically reduced or have vanished within the range of the snake, and our results quantitatively support upgrading this species’ threat level for extinction. This study can inform to programs to manage invasive snake populations and to conservation actions to recover the endemic lizard.

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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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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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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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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.