Iwasaki's snail-eater
Iwasaki's snail-eater '' is a species of snake in the family Pareidae. The species is endemic to the Yaeyama Islands in the southern Ryukyu Islands, Japan.
Etymology
The specific name, iwasakii, is in honor of Japanese meteorologist Takuji Iwasaki.Habitat
The preferred natural habitats of P. iwasakii are forest, shrubland, and grassland.Ecology
P. iwasakii is a snail-eating specialist; even newly hatched individuals feed on snails. It has asymmetric dentition on its jaws, with more teeth on the right mandible which facilitates feeding on snails with dextral shells. A consequence of this asymmetry is that P. iwasakii is much less adept at preying on sinistral snails. It systematically directs its attack on snails from the right in order to insert its lower jaw into the shell opening.The selection pressure of this predator on snails of the genus Satsuma has led to a significant increase in the proportion of snails with left-facing shells, known as levogyres, compared to snails with right-facing shells, known as dextrogyres, because the two forms have difficulty mating with each other. This proportion is a local originality, the levorotatory form being very rare on a worldwide scale.