''Hedleyella falconeri'', the giant panda snail, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of air-breathing

land snail A land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails. ''Land snail'' is the common name for terrestrial molluscs, terrestrial gastropod mollusks that have gastropod shell, shel ...

, a

terrestrial Terrestrial refers to things related to land or the planet Earth, as opposed to extraterrestrial. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on o ...

pulmonate Pulmonata or pulmonates is an informal group (previously an order, and before that, a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group inclu ...

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

in the family

Caryodidae Caryodidae is a Taxonomy (biology), taxonomic family (biology), family of air-breathing land snails, terrestrial molluscs, terrestrial pulmonate gastropod mollusks in the superfamily Acavoidea (according to the Taxonomy of the Gastropoda (Bouchet ...

. It is the largest species of land snail to be found in Australia.

Description

''Hedleyella falconeri'' has a

helicoid The helicoid, also known as helical surface, is a smooth Surface (differential geometry), surface embedded in three-dimensional space. It is the surface traced by an infinite line that is simultaneously being rotated and lifted along its Rotation ...

(spiral) shell which grows to a diameter of about 90mm (3.5"). The colour is some shade of brown marked with radially arranged irregular bands and splotches of black. When the snail is quiescent, the head and foot are retracted into the shell, but these are extended when the animal wants to move around and feed. The upper surface of head and foot has a reticulate pattern in grey and the foot is rimmed with orange. The head bears two pairs of retractable, dark-coloured

tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...

s, the upper pair, with the eyes on their tips, being twice as long as the lower pair. There is a dark line leading from between the tentacles along the nape of the neck.

Distribution and habitat

''Hedleyella falconeri'' is found in subtropical eastern Australia from Smiths Lake in

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

to just north of

Brisbane Brisbane ( ; ) is the List of Australian capital cities, capital and largest city of the States and territories of Australia, state of Queensland and the list of cities in Australia by population, third-most populous city in Australia, with a ...

. Its western limit is the

Great Dividing Range The Great Dividing Range, also known as the East Australian Cordillera or the Eastern Highlands, is a cordillera system in eastern Australia consisting of an expansive collection of mountain ranges, plateaus and rolling hills. It runs roughl ...

. It lives on the forest floor among

leaf litter Plant litter (also leaf litter, tree litter, soil litter, litterfall, or duff) is dead plant material (such as leaves, bark, needles, twigs, and cladodes) that has fallen to the ground. This detritus or dead organic material and its constituen ...

and

moss Mosses are small, non-vascular plant, non-vascular flowerless plants in the taxonomic phylum, division Bryophyta (, ) ''sensu stricto''. Bryophyta (''sensu lato'', Wilhelm Philippe Schimper, Schimp. 1879) may also refer to the parent group bryo ...

y logs and has not been observed to climb up trees to heights of more than .

Biology

''Hedleyella falconeri'' is

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

. It spends the day stationary and may hide itself under a rotting log or similar location but often remains in the open although it is usually at least partially covered in

. On most nights it starts to move around and feed, favouring wet nights. In a study, the average distance travelled by a snail in any night on which it moved was . It appeared to wander at random and did not seem to have a homing instinct. ''Hedleyella falconeri'' is a

fungivore Fungivory or mycophagy is the process of organisms consuming fungi. Many different organisms have been recorded to gain their energy from consuming fungi, including birds, mammals, insects, plants, amoebas, gastropods, nematodes, bacteria and othe ...

and feeds on the fruiting bodies of such fungi as '' Polyporus varius'' and the

bioluminescent Bioluminescence is the emission of light during a chemiluminescence reaction by living organisms. Bioluminescence occurs in multifarious organisms ranging from marine vertebrates and invertebrates, as well as in some fungi, microorganisms inc ...

fungus ''

Omphalotus nidiformis ''Omphalotus nidiformis'', or ghost fungus, is a gilled basidiomycete mushroom most notable for its bioluminescent properties. It is known to be found primarily in southern Australia and Tasmania, but was reported from India in 2012 and 2018. Th ...

''. It may also feed on rotting leaves on the forest floor. It is itself eaten by a number of birds including the

noisy pitta The noisy pitta (''Pitta versicolor'') is a species of bird in the family Pittidae. The noisy pitta is found in eastern Australia and southern New Guinea. It eats earthworms, insects and snails. Its natural habitats are temperate forests, subtro ...

(''Pitta versicolor'') which smashes the shell on a hard surface, the Albert's lyrebird (''Menura alberti'') and the

superb lyrebird The superb lyrebird (''Menura novaehollandiae'') is an Australian passerine songbird, one of two species from the family Menuridae, with the other being the much rarer Albert's lyrebird. It is one of the world's largest songbirds, and is re ...

(''Menura novaehollandiae''). ''Hedleyella falconeri'' is a

hermaphrodite A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic. The individuals of many ...

and mating usually occurs in February. Two snails come together overnight and each deposits a sac of sperm in a reproductive opening in the other. Fertilisation is internal and some time later, each snail lays a batch of up to twenty

eggs An egg is an organic vessel in which an embryo begins to develop. Egg, EGG or eggs may also refer to: Biology * Egg cell, the female reproductive cell (gamete) in oogamous organisms Food * Eggs as food Places * Egg, Austria * Egg, Switzerland ...

. These are cream coloured and nearly spherical, weigh and measure in diameter. The eggs are buried in a cavity under the leaf litter and take about six weeks to hatch. The juvenile snails that emerge are about long and grow slowly.

References

{{Taxonbar, from=Q3073900 Caryodidae Gastropods described in 1834 Gastropods of Australia