Manus Green Tree Snail

• The green is not in the calcareous shell, which is yellow, but in the periostracum: an extremely thin layer of protein covering it.
• It was one of the first invertebrates listed in Appendix II of CITES, in 1975, because of the demand for its shells for jewellery.
• It appears on the flag of Manus Province.
• Its shell is an intense green, an extremely rare colour in a snail — and what is more, the colour is not in the carbonate: the calcareous layer is yellow, and the green comes from a thin protein film covering it. When the animal dies and that layer peels away, the shell turns yellow.
• That colour turned it into a highly coveted object for jewellery, and collection for the international shell trade was so intense that the United States listed it under its Endangered Species Act in 1978, one of the very first invertebrates protected under that law.
• It is endemic to a single island, Manus, and to a very small area, which makes it especially vulnerable.
• The island's inhabitants have traditionally used it as an ornament, and today its collection is regulated.
• Its decline today owes more to deforestation than to collecting.

Skeleton type

Invertebrate - external calcareous shell (mollusc)

Habitat & environment

Tropical forest of Manus Island, up to about 700 m in altitude

Sources consulted: https://es.wikipedia.org/wiki/Papustyla_pulcherrima