The family Achatinellidae represents a diverse adaptive radiation. All species of tree-snail in Hawaii are believed to have come from a single ancestral snail. How that ancestral snail made the 3,800 kilometres (2,400 mi) trip across the ocean is unknown. A longstanding theory is that a bird carried a notably smaller ancestor across the ocean and dropped it on the islands, as bird mediated dispersal has been documented in other snail species. Alternative theories include that it floating across the ocean on a mat of debris, or that it island hopped across the Pacific in a combination of the theories.[2]
^Holland, Brenden S; Hadfield, Michael G (August 2004). "Origin and diversification of the endemic Hawaiian tree snails (Achatinellidae: Achatinellinae) based on molecular evidence". Molecular Phylogenetics and Evolution. 32 (2): 588–600. doi:10.1016/j.ympev.2004.01.003. PMID15223040.
^Barker G. M. Gastropods on Land: Phylogeny, Diversity and Adaptive Morphology. In Barker G. M. (ed.): The biology of terrestrial molluscs. CABI Publishing, Oxon, UK, 2001, ISBN0-85199-318-4. 1-146, cited pages: 139 and 142.
^Cooke, C. M. and Yoshio Kondo. 1960. Revision of Tornatellinidae and Achatinellidae (Gastropoda, Pulmonata). Bernice P. Bishop Museum, Bulletin 221. 303 pp.
^Kirch P. V., Christensen C. C. & Steadman D. W. (2009). "Subfossil Land Snails from Easter Island, Including Hotumatua anakenana, New Genus and Species (Pulmonata: Achatinellidae) 1". Pacific Science63(1): 105-122. PDF.