Partula is a genus of air-breathing tropical land snails, terrestrial pulmonate gastropod mollusks in the family Partulidae. Many species of Partula are known under the general common names "Polynesian tree snail" and "Moorean viviparous tree snail". Partulids are distributed across 5000 sqmi of Pacific Ocean islands, from the Society Islands to New Guinea. Once used as decorative items in Polynesian ceremonial wear and jewelry, these small snails (averaging about one-half to three-quarters of an inch in length) gained the attention of science when Dr. Henry Crampton (along with Yoshio Kondo) spent 50 years studying and cataloging partulids, detailing their remarkable array of morphological elements, ecological niches, and behavioral aspects that illustrate adaptive radiation.

Decline

The partulids of the island of Tahiti act as an example of the possible deleterious effects of attempted biological control. After an infestation of the introduced giant African land snails (Achatina spp.), the carnivorous Florida rosy wolfsnail (Euglandina rosea) was introduced into Tahiti in an attempt to combat the African species. Instead, the rosy wolfsnail hunted the nearly 76 species of Partula that were endemic to Tahiti and the nearby islands, causing all but 12 species to go extinct within a decade. Scientists were able to save 12 of these species prior to their becoming extinct. Today, the Zoological Society of London runs the Partula Programme Consortium which maintains a captive-breeding programme in the United Kingdom, France, and the United States. As of the 2024-1 update released on June 27, the IUCN Red List of Threatened Species contains 73 Partula species. Of these, 32 are listed as extinct, 10 are extinct in the wild, 17 are critically endangered, 8 are endangered, 2 are vulnerable and only 4 species are least concern. Individuals are being reintroduced to Tahiti from captive breeding programmes since 2014. In April 2023, over 5,000 individual snails from zoos in the United States and the United Kingdom were released on Tahiti and Mo'orea.

Species

Species within the genus Partula include:

Full list

Collected for ex situ conservation

The Partula that were collected for ex situ breeding include the following: Tahiti - P. affinis, P. clara, P. hyalina, P. nodosa, P. otaheitana Moorea - P. aurantia, P. mirabilis, P. mooreana, P. suturalis, P. taeniata, P. tohiveana Huahine - P. arguta, P. rosea, P. varia Raiatea - P. faba, P. garrettii (P. tristis), P. hebe, P. navigatoria (P. dentifera), P. turgida Marianas - P. gibba, P. langfordi P. garrettii and P. navigatoria were misidentified as the species in parentheses next to them.

Surviving species

The list of surviving species are as follows: Tahiti - P. affinis, P. clara, P. hyalina, P. incrassa, P. nodosa, P. otaheitana Moorea - P. mirabilis, P. mooreana, P. suturalis, P. taeniata, P. tohiveana Huahine - P. rosea, P. varia Raiatea - P. garrettii (P. tristis), P. hebe, P. meyeri, P. navigatoria (P. dentifera) Marianas - P. gibba, P. langfordi, P. lutaensis, P. radiolata Micronesia - P. emersoni, P. rufa Fiji - P. leefei, P. lirata Solomon Islands - P. cramptoni, P. micans Papua New Guinea - P. auraniana, P. similaris Cook Islands - P. assimilis

Cladogram

Phylogenetic analyses revealed that many of the Partula species are not monophyletic. The resulting cladogram is shown below.

Ecology

Partula species on Tahiti were usually found on the undersides of the leaves of Caladium and plantain, although in some valleys, they were frequently found on Dracaena and turmeric.

Gallery

Tahitian species

Moorean species

Huahine species

Raiatean species

Mariana Islands species