He found, using discriminant analysis and correlation analysis, that the snails fell into three main groups that showed a progressive change in relation to distance from the sea and shelter with the smallest shells being in exposed situations near the sea and the largest being in sheltered inland forest.
ambagiosus the shell height and shape were related to habitat type and exposure. Penniket ( 1981), Brook & Laurenson ( 1992) and Sherley ( 1996) examined the subspecific classifications of the New Zealand species of Placostylus in relation to morphometric analyses. They expressed doubt about whether the Marotere Islands (Hen and Chickens Islands) populations were endemic. hongii are native to the Poor Knights Islands and probably Mokohinau Islands and were taken from them to other islands and the mainland by Māori. Brook & McArdle ( 1999) concluded that P. hongii snails on islands may have resulted from being moved by Māori (Great Barrier Island, Mokohinau Islands, Marotere Islands and Poor Knights Islands) but this has not been confirmed (Climo 1973 Powell 1975, 1979 Hayward & Brook 1981 Triggs & Sherley 1993 Brook 1999). There are suggestions that some of the populations of P. hongii which also occurs in large numbers on 10 islands in the Poor Knights Islands (Brook & McArdle 1999 Brook 2002). Both North Island species survive in remnant populations occupying small areas except for P. Placostylus hongii occurs along the east coast of Northland between Whangaroa and Whangarei Heads and on some of the nearby islands (Powell 1979). 2008 Winterbourn 2009 Buckley & Bradler 2010 Buckley et al. 2003 Barker 2005 Larochelle & Larivière 2005 Marshall & Barker 2007 Chapple et al. Placostylus ambagiosus occurs naturally in the Te Paki/North Cape region at the northern end of the North Island, a well known area of endemism (e.g. arbutus was translocated from Manawatawhi/Great Island to South West Island, which appeared to lack Placostylus, in 2003 to provide prey for the endangered carnivorous snail Rhytidarex buddlei (Rhytitidae) (Brook & Whaley 2008). bollonsi was possibly due to translocation between the islands by Māori who once lived there (Powell 1948, 1951 Climo 1973). bollonsi also occurs on North East Island and West Island. All three occupy different areas of Manawatawhi/Great Island and P.
Placostylus bollonsi originally occurred on three islands in the Three Kings group, 56 km to the north of the New Zealand mainland. The islands where they are found now have no mammals whereas their locations on the mainland are susceptible to predation from introduced mammals such as rodents, pigs and hedgehogs (Parrish et al. Many also survive in habitat that has been modified by humans. All populations of Placostylus in New Zealand are highly restricted geographically-they occur either on islands or small areas of the mainland. Solem 1959 Goodacre & Wade 2001 Heller 2001 Townsend et al. ambagiosus are briefly arboreal whereas some species and closely related species overseas are arboreal as older juveniles or adults (e.g. The three New Zealand species of Placostylus are relatively large (50.0–113.5 mm) and mostly live on the ground where they feed on leaves that have fallen from broadleaf plants (Parrish et al. ambagiosus have been located but their taxonomic status is unknown (Brook 2002). ambagiosus were distinguished by Powell ( 1938, 1947, 1948, 1951) from differences in shell morphology and since then 15 new populations of P. Suter ( 1908) also added some details of the radula and reproductive organs for P. The three species of Placostylus in New Zealand were described using morphological characteristics of the shell including apical angles and ratios of height to maximum diameter, numbers of tubercles in the aperture, and colours of the periostracum and internal aperture. ambagiosus are ranked in the two highest threat classifications (Nationally Critical or Nationally Endangered) by Hitchmough et al. bollonsi and all but one population of P. bollonsi are considered range restricted whereas the other four populations of P. Placostylus hongii and one population of P. Powell 1947 Ramsay & Gardner 1977 Ogle 1979) and are now legally protected under the New Zealand Wildlife Act 1953 (Seventh Schedule). The New Zealand species of Placostylus have long been considered threatened (e.g. Two of the three species in New Zealand, Placostylus bollonsi Suter, 1908, and Placostylus ambagiosus Suter, 1906, currently include described subspecies whereas the third, Placostylus hongii Lesson, 1830, does not ( Table 1). Land snails in the genus Placostylus Beck, 1837 (Bulimulidae), known in New Zealand as flax snails, are among the most familiar members of New Zealand's unique invertebrate fauna although they also occur in Lord Howe Island, New Caledonia, and some other western Pacific Islands such Fiji, Vanuatu and the Solomons (Ponder et al.
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