Colorful Land Snails

Ancient land snails (air-breathing terrestrial pulmonate gastropods) originated during the Carboniferous Period, probably about 310 million years ago, which was about 165 million years after the first marine gastropods appeared.

More-modern land snails, like those mentioned below, are rare before the Cretaceous but are more plentiful in Cenozoic age (post- 66 million years ago) deposits. As fossils, they are useful to geologists because they are excellent indicators of the terrestrial environment, but their shells are susceptible to having been transported by streams into the marine environment. 

Many modern-day, air-breathing land snails from the tropics have intricate color bands on their shells. Unfortunately, color bands of both terrestrial (and marine shells) are only rarely preserved by fossilization.

The biggest shell is 3.5 cm in height.

Liguus virgineus (Linnaeus, 1758), also called the "rainbow snail" or "candy-stripes snail" air-breathing pulmonate is restricted to the islands of Haiti and Dominican Republic in the Caribbean Sea. They live in trees, thus they are arboreal. They feed on moss, fungi, an microscopic algae that cover the bark. In recent years, they have been over harvested for shell-craft trade. Also, the destruction of forests have become a major threat. The background color of the shell is creamy white, with narrow bright spiral stripes of red, green, blue, yellow, and purple. The slug-like animal itself is brown with black streaks. Genus Liguus belongs to family Orthalicidae.

Both shells are 3.5 cm in height.

 Amphidromus perversus (Linnaeus, 1758) is another tree snail, but its genus belongs to family Camaenidae. It lives in eastern India to northern Australia and especially in Indonesia (e.g., Sumatra, Java, Bali). The two specimens shown above display the asymmetry in shell coiling, which is common among this species. In fact, some populations simultaneously include the left-hand shell coiling (sinistral) and the right-hand shell coiling (dextral). This is a rare biologic phenomenon, and the reasons for it are still being researched. There is also much color variation among this species and its subspecies.

2.7 cm height

Helicostyla roissyana (Férussac, 1840) is the "chocolate-swirl" snail. It is another air-breathing land snail, but it belongs to family 
Bradybaenidae. This snail is endemic to the Philippines. 

The largest shell is 3.2 cm height.

Helicostyla annulata (Sowerby, 1841) is a tree snail, belonging to family Bradybaenidae. The unbounded  yellow to pale-yellow forms are shown here, but there is also a banded form. Helicostyla annulata is common in the Philippines.

                    

   

Ryssota ovum Valenciennes, 1854 is a tree snail restricted to rain forests in the Philippines. It can also live in branch and leaf debris at the tree base. This species is large sized, and the specimen shown here is 7 cm in diameter. The common name of this snail is the "Polished Muffin Snail." Some people consider the meat of this snail to be a delicacy, and its shell is used as a water vessel. The genus belongs to family Helicarionidae.