Brown Tree Skink

The Brown Tree skink or Green Tree Skink, Prasinohaema virens, is a scincid lizard species native to New Guinea. The species is poorly studied and the species' risk of extinction has not been evaluated by the World Conservation Union, and does not appear in any cities. The skink has developed setae on its toepads (or digit pads) for climbing analogous to those of geckos and anoles, but the trait is believed to have evolved independently to these groups, and so is an example of convergent evolution. With regards to the trait, other species in the genus, P. flavipes and P. prehensicauda have the primitive character, and lack the setae. Other skinks within the genra Lipinia have also evolved toepad setae, and within the skink family four morphologically distinct adhesive microstructures have evolved, possibly all with independent evolutionary origins. By contrast, anoles and geckos each use a single, common structure, although it appears to have evolved independently in the two groups. Like other lizards of the genera Prasinohaema, P. virens has a green-blood pigmentation, rather than the usual light yellow colouration of most vertebrates. The green blood pigmentation results in a strikingly bright lime-green colouration of muscles, bones, tongue, and mucosal tissue. The green colouration of the blood is the result of the accumulation of the bile pigment biliverdin, a compound that is toxic to virtually all vertebrates.