Family ACHATINELLIDAE Gulick, 1873

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Introduction

Achatinellids are herbivores, feeding on biofilm found growing on the leaf and bark surfaces on which they live. They have a short broad foot with very sticky, viscous mucus which can be drawn out in strands. Both oviparous and ovoviviparous forms occur and sometimes juveniles can be seen through the transparent shells of the adults.
Most Australian species are arboreal and live in rainforests and vine thickets in coastal and sub-coastal areas. Strand line populations can also live in dense grass mats growing on dunes where they often occur in large densities.
Achatinellids are an exclusively Indo-Pacific family where their occurrence may be both natural and anthropogenic in nature. Those from Indian Ocean islands and the Australian mainland may possibly have been transported by humans.
Smith (1992) lists 12 species, and Stanisc et al. (2010) provides an updated list, synonymies and distribution details for eastern Australian species.

Diagnosis

Achatinellids have very small, conical to elongate shells with whorls that are generally rounded. Sutures are moderately indented and most species lack an umbilicus. The lip is simple and not reflected. The aperture is oval in shape and the columella is spirally twisted to straight and may have a small lamella in some species. A small lamella is also usually present on the parietal wall. Apertural barriers vary in size during the growth of the shell and juveniles generally have more prominent barriers compared to adults. Sculpture in Australian species may be smooth or consist of fine incised spiral lines. Shell colour varies from white to amber or dark brown. However many brightly coloured forms are found on the Hawaiian islands and species with unusual and complex apertural barriers, shell sculpture and shape are found on other islands of the central south Pacific.

Diagnosis References

Stanisic, J., Shea, M., Potter, D. & Griffiths, O. 2010. Australian Land Snails. A field guide to eastern Australian species. Mauritius : Bioculture Press Vol. 1 595 pp. [90]

General References

Cooke, C.M. & Kondo, Y. 1960. Revision of Tornatellinidae and Achatinellidae (Gastropoda: Pulmonata). Bulletin of the Bernice P. Bishop Museum 221: 1-303

Iredale, T. 1937. A basic list of the land Mollusca of Australia. The Australian Zoologist 8: 287-333 [12 Mar. 1937] [299-300]

Iredale, T. 1944. The land Mollusca of Lord Howe Island. The Australian Zoologist 10: 299-334 [10 May 1944] [307-308]

Iredale, T. 1945. The land Mollusca of Norfolk Island. The Australian Zoologist 11: 46-71 [51-52]

Smith, B.J. 1992. Non-Marine Mollusca. In, Houston, W.W.K. (ed.). Zoological Catalogue of Australia. Non-marine Mollusca. Canberra : Australian Government Publishing Service Vol. 8 xii 408 pp. [86-88]

Smith, B.J. & Kershaw, R.C. 1979. Field Guide to the Non-marine Molluscs of South-eastern Australia. Canberra : A.N.U. Press 285 pp.

Solem, A. 1989. Non-camaenid land snails of the Kimberley and Northern Territory, Australia. I. Systematics, affinities and ranges. Invertebrate Taxonomy 2(4): 455-604

Stanisic, J. 1998. Superfamily Achatinelloidea. pp. 1080-1081 in Beesley, P.L., Ross, G.J.B. & Wells, A. (eds). Mollusca: The Southern Synthesis. Fauna of Australia. Melbourne : CSIRO Publishing Vol. 5(Part B) pp. vi–viii, 565–1234.

Stanisic, J., Shea, M., Potter, D. & Griffiths, O. 2010. Australian Land Snails. A field guide to eastern Australian species. Mauritius : Bioculture Press Vol. 1 595 pp. [90-93]

Zilch, A. 1959. Gastropoda. Teil 2. Euthyneura. In, Schindewolf, O.H. (ed.). Handbuch der Paläozoologie. Berlin-Zehlendorf : Bornträger Vol. 6(2)(2) xii 834 pp. [132]

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