Caryodids are large-sized snails (some very large) with variable shell form – elongately conical to globose, discoidal and ear-shaped. Shell thickness also varies significantly from thin and fragile to extremely thick and solid. Whorls are rounded, bluntly angled or keeled and sutures are generally moderately impressed. Spire height varies from elongate conical to flat. Sculpture varies from relatively smooth with fine incised spiral lines or wrinkles to strong spiral striae, corrugated spiral ribs or well defined radial growth lines. Sculpture may be differentiated between the juvenile (protoconch) and adult (teleoconch) or between upper and lower shell surfaces. Apertures are lunate to ovate and shells are widely umbilicate to imperforate. Lips vary from greatly thickened and reflected to thin and undifferentiated. Usually there is a small columellar kink or twist. The periostracum is generally well developed and strongly coloured. Shell colour varies from brown to yellow and may be patterned with spiral bands, flames, zigzags, broken lines and spots.
Caryodids are oviparous and produce large oval-shelled eggs similar to those of some birds. The animals are often strikingly coloured with dorsal stripes and differently coloured tentacles. The foot is large and broad and is usually heavily wrinkled and furrowed. They are herbivores usually feeding on decayed plant material and fungi. They are mainly terrestrial however juveniles of some species will climb trees up to a few metres in wet weather. All species are nocturnal and live under accumulations of forest floor debris, logs, rock piles and about the root systems of fig trees. Caryodids are predated by a number of animals, however the most notable are Pitta birds which smash the shells (particularly Pedinogyra spp.) against stones (anvils) on the forest floor, often accumulating considerable piles of broken shells around favoured anvil stones after many years. Caryodids are also eaten by feral pigs.
Caryodids live in a variety of habitats along the east coast and ranges from coastal heathland and woodland through to rainforest, dry vine thickets, brigalow, sub-alpine woodland and tussock grassland. They occur from mideastern Queensland (Proserpine) south to Tasmania. There are about 18 species known from eastern Australia (including Tasmania). The family includes Australia’s largest landsnail, Hedleyella falconeri, which reaches up to 90 mm in shell diameter.
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References
Dartnall, A.J. & Dartnall, J.A. 1972. Notes on the reproductive anatomy and cytogenetics of some Australian acavacean molluscs. Australian Journal of Zoology 20: 79-81.
Kershaw, R.C. 1988. A study of the Caryodidae (Pulmonata). Part I. Anoglypta launcestonensis (Reeve, 1853). Records of the Queen Victoria Museum Launceston 93: 1-24.
Kershaw, R.C. 1988. A study of the Caryodidae (Pulmonata). Part II. Caryodes dufresnii (Leach, 1815). Records of the Queen Victoria Museum Launceston 94: 1-27.
Kershaw, R.C. 1989 A study of the Caryodidae (Pulmonata). Part III: Subspecies of Caryodes dufresnii (Leach, 1815). Records of the Queen Victoria Museum Launceston 97: 1-25.
Murphy, M.J. 2002. Observations on the behaviour of the Australian land snail Hedleyella falconeri (Gray, 1834) (Pulmonata: Caryodidae) using the spool-and-line technique. Molluscan Research 22:149-164.
Smith, B.J. 1998. Family Caryodidae. P. 1093 in Beesley, P.L., Ross, G.J.B. & Wells, A. (eds) Mollusca: The Southern Synthesis. Fauna of Australia. Vol. 5. CSIRO Publishing: Melbourne, Part B viii, 565-1234pp.
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