The following is a list of terrestrial snails found in the Mariana Islands. The general term for land snails in Chamorro is akaleha’. It has been estimated there are about 100 species of land snail on Guam, the southernmost Mariana Island, but about 20 of these have been introduced by human activities.
Conservation
Nearly all of the native species of land snail are in decline throughout the Mariana Islands, and many have not been seen for decades. Some of the following species have not been seen since the time they were first collected. The southern islands of the Mariana archipelago are now almost devoid of native land snails. Land snails face threats from habitat destruction and from introduced predatory snails. The predatory Gonaxis snails and rosy wolfsnails (Euglandina rosea) were introduced as biocontrols against the invasive giant African land snail (Lissachatina fulica), but they also reduced the population of native snails. Since then, all three of these species are now reduced by another biocontrol, the New Guinea flatworm (Platydemas manokwari), which is also predating native snails.
The tiny islet of Alupat off Guam has been identified as a potential site for a snail preserve, as it has not been invaded by New Guinea flatworms, rosy wolfsnails, or Gonaxis snails.
Endemic snails
Assimineidae (palmleaf snails)
Allepithema spp. - two undescribed species of Allepithema have been reported. Allepithema fulvum - Guam Allepithema glabratum - Guam Allepithema pyramis - Guam Allepithema quadrasi - Guam and possibly Rota and Tinian Allepithema tuberculatum - Guam Allepithema turritum - Guam Chalicopoma laevigatum - Guam and Rota Chalicopoma semicostulatum - Guam and Rota Omphalotropis cookei - Guam, Rota, Saipan and Sarigan Omphalotropis elegans - Guam and Rota Omphalotropis elongatula - Guam and Rota. Identified on Cocos and Alupat islands between 2016 and 2019. Omphalotropis erosa - Guam and Sarigan Omphalotropis gracilis - Guam Omphalotropis guamensis - Guam Omphalotropis laticosta - Guam Omphalotropis latilabris - Guam Omphalotropis ochthogyra - Guam and Rota Omphalotropis picta - Guam Identified on Alupat Island off Guam between 2016 and 2019 Omphalotropis pilosa - Guam Omphalotropis quadrasi - Guam and Rota Has been identified on Guam as late as 2024. Omphalotropis suturalis - Guam and Rota Omphalotropis sp. - five undescribed species from subfossil deposits in Rota Omphalotropis sp. - an undescribed species from Rota Paludinella conica - Guam, Rota, Saipan, Sarigan Quadrasiella clathrata - Guam Quadrasiella mucronata - Rota and Tinian
Diplommatinidae (staircase snails)
Palaina hyalina - Guam, Sarigan, Aguiguan Palaina taeniolata - Guam, Rota, Saipan, Aguiguan Identified on Alupat and Cocos islands off Guam between 2016 and 2019, and on Guam in 2022
Hydrocenidae
Georissa biangulata - Guam and Sarigan Has been identified on Guam in 2024. Georissa elegans - Guam, Rota, Aguiguan Georissa laevigata - Rota and Aguiguan Identified on Alupat and Cocos islands off Guam between 2016 and 2019
Truncatellidae (looping snails)
Taheitia alata - Guam Taheitia lamellicosta - Guam Taheitia parvula - Guam Taheitia subauriculata - Guam Truncatella expansilabris - Guam
Achatinellidae
Elasmias quadrasi - Guam, Rota, Aguiguan, TInian, Saipan, possibly Anatahan, Alamagan, Agrihan, Asuncion and Maug. Has been identified on Guam and Saipan as late as 2024. Lamellidea microstoma - Guam, Rota, Tinian, Saipan, possibly Sarigan, Alamagan, Agrihan, Asuncion and Maug Lamellidea moellendorffiana - Guam, Rota, Tinian, Saipan, possibly Sarigan, Alamagan, Agrihan, Asuncion and Maug Lamellidea subcylindrica - Guam and Rota, possibly Sarigan, Alamagan, Agrihan, Asuncion and Maug
Charopidae
Himeroconcha fusca - Guam Himeroconcha lamlanensis - Guam Himeroconcha quadrasi - Guam and Rota Himeroconcha rotula - Guam and Rota Ladronellum mariannarum - Guam Semperdon heptaptychius - Rota and northern Guam Semperdon rotanus - Rota
Euconulidae
Lamprocystis denticulata - Guam, Rota and Saipan Lamprocystis fastigata - Guam, Rota, and Tinian Lamprocystis hornbosteli - Guam Lamprocystis misella - Guam
Partulidae
Partula gibba (Fat Guam partulid) - Guam, Rota, Aguiguan, Tinian, Saipan, Anatahan, Sarigan, Alamagan, and Pagan. CRITICALLY ENDANGERED (IUCN) Partula langfordi (Langford's tree snail) - Aguiguan; EXTINCT (IUCN) Partula radiolata (Guam streaked tree snail) - Guam. CRITICALLY ENDANGERED (IUCN) Partula salifana (Mount Alifana partula) - Guam; EXTINCT (IUCN) Samoana fragilis (Fragile tree snail) - Guam and Rota. CRITICALLY ENDANGERED (IUCN)
Succineidae (amber snails)
Succinea guamensis - Guam Succinea piratarum - Guam. ENDANGERED (IUCN) Succinea quadrasi - Guam. ENDANGERED (IUCN) Succinea species - Guam. Unidentified species house in the Bernice P. Bishop Museum reported by B.D. Smith
Vertiginidae (whorl snails)
Nesopupa quadrasi quadrasi - Guam, possibly also Rota, Aguiguan, Tinian and Saipan Nesopupa sp. - undescribed species
Pupillidae
Ptychalaea sp. - undescribed species from Sarigan, Alamagan, Pagan, Agrihan, Asuncion, and Maug
Non-endemic, possibly native snails
Assimineidae (palmleaf snails)
Omphalotropis granum - known from Australia, Melanesia and Micronesia; found on Guam, Saipan and Rota Identified on Alupat and Cocos islands off Guam between 2016 and 2019
Truncatellidae (looping snails)
Taheitia mariannarum - widespread in Pacific, common on Guam, Rota and Saipan Identified on Alupat and Cocos islands off Guam between 2016 and 2019 Truncatella guerinii - widespread distribution; found on Guam and Saipan
Ellobiidae (hollow-shelled snails)
Melampus castaneus - widespread in western and central Pacific. Pythia scarabaeus - widespread in western Pacific; found on Guam, Rota, Aguiguan and Saipan Identified on Alupat and Cocos islands off Guam between 2016 and 2019
Euconulidae
Liardetia sculpta - found from China to Micronesia; in the Marian Islands, found on Guam and Rota Liardetia tenuisculpta - found from Philippines to Micronesia; in the Mariana Islands, found on Guam and Rota
Introduced species
Achatinidae
Lissachatina fulica (Giant African land snail) - introduced to the Guam in 1945, and to Rota, Tinian, Saipan, Pagan and Agrihan between 1936 and 1939
Achatinellidae
Pacificella variabilis - widespread in Pacific; found on Guam and Rota, possibly Sarigan, Alamagan, Agrihan, Asuncion and Maug
Assimineidae (palmleaf snails)
Assiminea parvula guamensis - native to Philippines; found on Guam
Bradybaeninae
Bradybaena similaris (Asian trampsnail)- native to Asia but introduced to Mariana Islands in 1948; found in Guam and Saipan
Bulimulidae
Mesembrinus multilineatus (lined treesnail) - native to the Americas, but introduced to Guam, likely from cultivated plants, before 1978
Camaenidae
Satsuma succincta - native to Taiwan, first found on Guam in 1982
Euconulidae
Coneuplecta calculosa (Tropical beehive snail) - known from India to Polynesia; in the Mariana Islands, found only on Agrihan Liardetia doliolum - probably native to Philippines; in the Mariana Islands, found on Guam, Tinian and Rota
Ferussaciidae
Cecilioides aperta - native to Caribbean; found on Guam, possibly Sarigan and Alamagan
Spiraxidae
Euglandina rosea (rosy wolfsnail) - native to southeast US but introduced to Pacific Islands and Asia by 1957; found on Guam, Saipan and Agrihan
Streptaxidae
Gonaxis kibweziensis - native to tropical east Africa; introduced to Aguiguan in 1950, Guam in 1954, and Pagan by 1992 Gonaxis quadrilateralis - native to tropical east Africa; introduced to Guam in 1967; also introduced to Saipan by 1979 but may not have established Huttonella bicolor - native to Asia or Africa; perhaps a prehistoric introduction to Pacific Islands; found on Guam, Saipan and Pagan
Subulininae
Allopeas gracile (graceful awlsnail) - probably native to New World tropics; in the Marianas, known from Guam, Tinian and Saipan, possibly Agrihan, Alamagan, Asuncion, Guguan, Maug, Pagan, and Sarigan Opeas hannense (dwarf awlsnail) - probably native to New World tropics Paropeas achatinaceum - native to Indonesia; found on Guam and Sarigan Subulina octona - native to New World tropics but prehistorically introduced to Pacific Islands; found on Guam, Aguiguan, Tinian, Saipan, Anatahan, and Pagan
Succineidae (amber snails)
Succinea luteola (Mexico ambersnail) - native to southeast US, but introduced to Guam by 2012
Valloniidae
Pupisoma dioscoricola - native to South Africa through southern Asia and Japan; introduced widely in the Pacific; found on Sarigan, Alamagan, Pagan, Agrihan, Asuncion, and Maug
Veronicellidae (leatherleaf slugs)
Veronicella cubensis (Cuban slug) - native to Cuba; introduced to Guam in 1993 and Rota in 1997 Laevicaulis alte (tropical leatherleaf) - native to central Africa; found on Alamagan Sarasinula plebeia (bean slug) - native to Brazil and Caribbean; found on Tinian and Saipan
Vertiginidae (whorl snails)
Gastrocopta pediculus - probably native to Philippines and southeast Asia; found on Rota, Sarigan, Guguan, Alamagan Asuncion and Maug Gastrocopta servilis - native to west India; found on Guam and Saipan, possibly Rota, Sarigan, Guguan, Alamagan Asuncion and Maug
See also
References