A visitor from Queensland ?

This photo was sent in by our regular contributors from “Three Sisters”, Flowerdale, with the question “What is it, worm or leech?” It had us baffled, so it was another case of consult the experts, and the obvious person to ask was Max Campbell, the speaker at the most recent Focus on Fauna presentation on Invertebrates. Max identified the creature as a terrestrial flatworm, or land planarian, and put us in contact with Dr Leigh Winsor, a world authority on flatworms, who confirmed that it was indeed a flatworm, Caenoplana coerulea Moseley, which is in fact a complex of 3 or 4 closely related species, one of which is native to Queensland but has proved to be a great traveller in potted plants, and has turned up in many parts of the world, becoming a pest in some places by seriously depleting earthworm numbers.

Given that the pictured specimen (about 10 cm long) was found in a domestic setting with a predominately exotic garden, it is almost certainly the Queensland species of “Caenoplana coerulea“. It is nocturnal and shelters by day beneath pot plants or pavers, or in cracks in stone walls. It is generally beneficial around the garden and has been reported to be a predator of the introduced pest, the black Portuguese millipede.

Leigh also provided us with a wonderfully informative fact sheet which can be viewed by clicking on INFOSHEET Terrestrial Flatworms.