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Australia’s fascinating land snails

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Australia has many amazing land snails. There are currently about 1,500 described species and another 1,000 waiting to be named. Snails have a full shell and slugs have no external shell, but there are also semi-slugs, which have a half shell! Many species live in forests in the wetter areas of the continent but some also inhabit rocky outcrops in the seasonally dry Kimberley and the arid Red Centre.

Opalescent pendant-snail (Leptopoma perlucida)

This tree-dwelling snail is from the Wet Tropics and Cape York Peninsula of northern Queensland. It has an operculum (visible on the back of the foot) which is a trapdoor that closes the mouth of the snail’s shell. Australia has about 100 species of operculate snails.

Photo: Neil Hewett

Harriett’s carnivorous snail (Austrorhytida harriettae)

A carnivorous land snail from mid-eastern New South Wales. Carnivorous land snails feed on earthworms and animals that live in leaf litter, including other snails! They have specialised dagger-like teeth for tearing flesh. The long neck is a feature that enables the snail to enter the shells of their prey.

Photo: John Stanisic

Grey-blotched semi-slug (Fastosarion griseola)

A semi-slug from south-eastern Queensland. Semi-slugs have a reduced shell that may be ear-shaped or plate-like that sits on the back of the animal. The flaps of tissue that cover the shell are called ‘accessory breathing surfaces’, and they absorb oxygen directly from the air.

Photo: John Stanisic

Red-triangle slug (Triboniophorus graeffei)

One of only a handful of native slug species. It comes in a range of colours, including white, green, orange and red. The golden form comes from the Border Ranges of south-eastern Queensland. The red-triangle slug typically feeds on algae and other micro-organisms growing on rocks and the trunks of trees. 

Photo: John Stanisic

Mitchell’s rainforest snail (Thersites mitchellae)

A critically endangered land snail from rainforests in north-eastern New South Wales. The snail’s habitat has been largely destroyed by clearing for farming and urban development. This species is one of many native land snails that face a precarious future.

Photo: John Stanisic


If you enjoyed this article…

Dr John Stanisic is one of the authors of A Guide to Land Snails of Australia. Check out this book to trek through some of Australia’s spectacular regional landscapes and learn about the snails that call these areas home. This book is available to purchase on the CSIRO Publishing website and from all good bookstores.


4 responses

  1. Susan Macdonald Avatar
    Susan Macdonald

    So beautiful! And diverse.

  2. John Taylor Avatar
    John Taylor

    Hi, I am not sure if anyone can help me with advice on something I found in my garden today. I found what I though was a river stone in the lawn but when I touched it, it moved in response. Size was approximately 70mm x 30mm and 25 mm thick at the highest point and the shape was as mentioned, just like a smooth river stone. Colour was a dark brown/grey and was consistent across the upper surface the under side revealed a very small mouth and two tiny (3mm) antennae probes – possibly eyes. In a total lapse of logic I released it into the bush reserve behind my home in Yamba NSW without photographing first.

    1. David Shaw Avatar
      David Shaw

      Hi John,
      That’s a really tricky question! It’s a shame you didn’t get a photo because they’re really useful. When I have something I want help identifying, I usually put a photo up on inaturalist.org – there are a huge number of experts there who are ready to help.

      If you want to puzzle it out, I’d start by making sure you know what animal type it was. I think you might be describing a slug, but did it have any legs?

      If you’re sure it was a slug, go to your local library and see if they can order in ‘A Guide to Land Snails of Australia’.

      Cheers,
      David

  3. John Taylor Avatar
    John Taylor

    Thanks David

    Just confirming it did not have any legs. I think you are correct in it being a slug and from what we have found I would expect it is a tropical Leatherleaf (aka Laevicaulis alte). If I find it again I will certainly photograph it.

    Thank you very much for getting back to me and I will certainly follow up with the reference book you have suggested.

    All the best

    John Taylor

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