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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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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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In this study we compile data regarding lizard densities of the island populations of the Ibiza wall lizard, Podarcis pityusensis, which can serve as a baseline for future research and control of the invasive snakes, and in particular the horseshoe whip snake Hemorrhois hippocrepis, in the Pityusic Islands. Special attention has been given to the correct official spelling of 96 locations of which 89 are real rocks, islets and islands. For each island a short description, toponymy, faunal and floral aspects and some herpetological history is given, and a lizard density value was assigned. The results are very disturbing, with two confirmed- and three most likely extinct island populations of Podarcis pityusensis, and we call for coordinated action.

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The Ibiza wall lizard (Podarcis pityusensis), has a very limited distribution, being located only in the Pitiusas Islands of Balearic Islands, which are Ibiza and Formentera. In the Red List of Threatened Species of IUCN (International Union for the Conservation of Nature), this species went from being classified as `Near Threatened` (NT) and became `Endangered` (EN) on the 27th of June. This change in its category is due to a population decrease of more than 50% since 2010. The main reason for this population reduction is due to predation by invasive snake species, especially the horseshoe whip snake (Hemorrhois hippocrepis), which was accidentally introduced into the islands in 2003 and has since been a major threat to the lizard. Because its conservation status has recently been rectified, the recovery plan that it should have as being classified as an endangered species by IUCN has not yet been published. Thus, in this end-of-degree work it is intended to carry out this recovery plan for the Ibiza wall lizard (Podarcis pityusensis). This will include a review of the current status of the species (population status, critical areas, threats, etc.), definition of a set of objectives for the plan and identification of measures necessary to achieve the objectives, eliminate the threats facing the species, to restore their populations and ensure their long-term viability.