Italian wall lizard
|Italian wall lizard|
The Italian wall lizard, ruin lizard, or İstanbul lizard (Podarcis sicula from the Greek meaning 'agile' and 'feet') is a species of lizard in the family Lacertidae. P. sicula is native to Bosnia and Herzegovina, Croatia, France, Italy, Serbia and Montenegro, Slovenia and Switzerland, but has also been introduced to Spain, Turkey, and the United States. P. sicula is the most abundant lizard species in southern Italy.
P. sicula gained attention in 2008 following the publication of a research study that detailed distinct morphological and behavioral changes in a P. sicula population indicative of "rapid evolution".
Its natural habitats are Mediterranean-type shrubby vegetation, rocky areas, rocky shores, sandy shores, rural gardens, pastureland, plantations and urban areas.
P. sicula contains dozens of subspecies. The current distribution patterns of the subspecies have been interpreted as the consequence of natural events, including regional glacial refuges and postglacial area expansions, and multiple introductions by man.
The island endemic Santo Stefano lizard (P. s. sanctistephani) became extinct in 1965 after introduction of predators, interbreeding with introduced wall lizards, and a disease epidemic which wiped out the last remnants.
In 1971, ten adult P. sicula specimens from the island of Kopište were transported 3.5 km east to the island of Mrčara (both Croatian islands lie in the Adriatic Sea near Lastovo), where they founded a new bottlenecked population. The two islands have similar size, elevation, microclimate, and a general absence of terrestrial predators and the P. sicula expanded for decades without human interference, even outcompeting the (now extinct) local Podarcis melisellensis population.
Following the Yugoslav Wars in the 1990s, scientists returned to Mrčara and found that the lizards currently occupying Mrčara differ greatly from those on Kopište. While mitochondrial DNA analyses have verified that P. sicula currently on Mrčara are genetically very similar to the Kopište source population, the new Mrčara population of P. sicula was described, in August 2007, as having a larger average size, shorter hind limbs, lower maximal sprint speed and altered response to simulated predatory attacks compared to the original Kopište population. These population changes in morphology and behavior were attributed to "relaxed predation intensity" and greater protection from vegetation on Mrčara.
In 2008, further analysis revealed that the Mrčara population of P. sicula have significantly different head morphology (longer, wider, and taller heads) and increased bite force compared to the original Kopište population. This change in head shape corresponded with a shift in diet: Kopište P. sicula are primarily insectivorous, but those on Mrčara eat substantially more plant matter. The changes in foraging style may have contributed to a greater population density and decreased territorial behavior of the Mrčara population.
The most surprising difference found between the two populations was the discovery, in the Mrčara lizards, of cecal valves, which slow down food passage and provide fermenting chambers, allowing commensal microorganisms to convert cellulose to nutrients digestible by the lizards. Additionally, the researchers discovered that nematodes were common in the guts of Mrčara lizards, but absent from Kopište P. sicula, which do not have cecal valves. The cecal valves, which occur in less than 1 percent of all known species of scaled reptiles, have been described as an "adaptive novelty, a brand new feature not present in the ancestral population and newly evolved in these lizards".
- Isailovic, J.C., Vogrin, M., Corti, C., Mellado, V.P., Sá-Sousa, P., Cheylan, M., Pleguezuelos, J., Sindaco, R., Romano, A. & Avci, A. (2009). "Podarcis sicula". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 26 August 2012.
- De Falco M, Sciarrillo R, Virgilio F, et al. (August 2004). "Annual variations of adrenal gland hormones in the lizard Podarcis sicula". J. Comp. Physiol. A Neuroethol. Sens. Neural. Behav. Physiol. 190 (8): 675–81. doi:10.1007/s00359-004-0528-1. PMID 15170520.
- Herrel A, Huyghe K, Vanhooydonck B, et al. (March 2008). "Rapid large-scale evolutionary divergence in morphology and performance associated with exploitation of a different dietary resource". Proc. Natl. Acad. Sci. U.S.A. 105 (12): 4792–5. doi:10.1073/pnas.0711998105. PMC 2290806. PMID 18344323.
- "National Geographic: Lizards Rapidly Evolve After Introduction to Island". Retrieved 2008-05-27.
- "UMass Amherst : In the Loop : Talking Points : Lizards undergo rapid evolution after introduction to new home, says researcher". Retrieved 2008-05-27.[dead link]
- "Science Daily: Lizards Undergo Rapid Evolution After Introduction To A New Home". Retrieved 2008-05-27.
- PZ Myers "Pharyngula: Still just a lizard". Retrieved 2008-05-27.
- "Newswise: Lizards Undergo Rapid Evolution After Introduction to New Island". Retrieved 2008-08-06.
- "TYPICAL LIZARDS (Lacertidae): Podarcis sicula ssp". Retrieved 2008-06-02.
- Podnar M, Mayer W, Tvrtković N (February 2005). "Phylogeography of the Italian wall lizard, Podarcis sicula, as revealed by mitochondrial DNA sequences". Mol. Ecol. 14 (2): 575–88. doi:10.1111/j.1365-294X.2005.02427.x. PMID 15660947.
- Bart Vervust, Irena Grbac, Raoul Van Damme (August 2007). "Differences in morphology, performance and behaviour between recently diverged populations of Podarcis sicula mirror differences in predation pressure". Oikos 116 (8): 1343–1352. doi:10.1111/j.0030-1299.2007.15989.x.
- Foá A, Bertolucci C (May 2003). "Toward a seasonal model of the circadian system: the case of Ruin lizards". Front. Biosci. 8: s236–42. doi:10.2741/1037. PMID 12700027.
- Media related to Podarcis sicula at Wikimedia Commons