Subphylum Vertebrata Rank Species | Phylum Chordata Genus Podarcis Higher classification Podarcis | |
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Similar Podarcis, Podarcis muralis, Reptile, Lacertids, Lacerta | ||
Evolution of the 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.
Contents
- Evolution of the italian wall lizard
- Italian wall lizard
- Habitat
- Subspecies
- Rapid adaptation
- As an introduced species
- Other research
- References
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".
Italian wall lizard
Habitat
Its natural habitats are Mediterranean-type shrubby vegetation, rocky areas, rocky shores, sandy shores, rural gardens, pastureland, plantations and urban areas.
Subspecies
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.
List of subspecies: Podarcis sicula adriaticus, Podarcis sicula aemiliani, Podarcis sicula amparoae, Podarcis sicula astorgae, Podarcis sicula bagnolensis, Podarcis sicula bolei, Podarcis sicula calabresiae, Podarcis sicula campestris, Podarcis sicula caporiaccoi, Podarcis sicula cattaroi, Podarcis sicula cettii, Podarcis sicula ciclopica, Podarcis sicula coeruleus, Podarcis sicula cucchiarai, Podarcis sicula dupinici, Podarcis sicula fiumanoideus, Podarcis sicula flavigulus, Podarcis sicula gallensis, Podarcis sicula hadzii, Podarcis sicula hieroglyphicus, Podarcis sicula insularus, Podarcis sicula klemmeri, Podarcis sicula kolombatovici, Podarcis sicula laganjensis, Podarcis sicula lanzai, Podarcis sicula latastei, Podarcis sicula massinei, Podarcis sicula monaconensis, Podarcis sicula nikolici, Podarcis sicula palmarolae, Podarcis sicula pasquinii, Podarcis sicula paulae, Podarcis sicula pelagosae, Podarcis sicula pirosoensis, Podarcis sicula pohlibensis, Podarcis sicula premudanus, Podarcis sicula premudensis, Podarcis sicula pretneri, Podarcis sicula radovanovici, Podarcis sicula ragusae, Podarcis sicula salfii, Podarcis sicula samogradi, Podarcis sicula sanctinicolai, †Podarcis sicula sanctistephani, Podarcis sicula sicula, Podarcis sicula tyrrhenicus, Podarcis sicula vesseljuchi.
Rapid adaptation
In 1971, ten adult specimens of Podarcis sicula (the Italian wall lizard) were transported from the Croatian island of Pod Kopište to the island Pod Mrčaru (about 3.5 km to the east). Both islands lie in the Adriatic Sea near Lastovo), where the lizards 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 out-competing the (now locally extinct) Podarcis melisellensis population.
In the 1990s, scientists returned to Pod Mrčaru and found that the lizards currently occupying Mrčaru differ greatly from those on Kopište. While mitochondrial DNA analyses have verified that P. sicula currently on Mrčaru are genetically very similar to the Kopište source population, the new Mrčaru population of P. sicula was described 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 Mrčaru.
In 2008, further analysis revealed that the Mrčaru 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 Mrčaru eat substantially more plant matter. The changes in foraging style may have contributed to a greater population density and decreased territorial behavior of the Mrčaru population.
Another difference found between the two populations was the discovery, in the Mrčaru 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 Mrčaru 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".
As an introduced species
Populations of P. sicula in North America have been documented from Topeka, Kansas, Long Island, New York and Greenwich, Connecticut. The species seems to be extending its range from an initial colonization event in western Long Island, presumably by using railroad tracks as dispersal corridors. On the west coast, ''P. sicula'' was introduced to San Pedro, California in 1994 by a traveler coming back from the island of Sicily.
Other research
P. sicula has served as an animal model for many areas of research, including investigations of circadian rhythms.