Rhynchodemus sylvaticus

Crace Grasslands

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Identification history

Rhynchodemus sylvaticus	29 Mar 2024	turb
Rhynchodemus sylvaticus	29 Mar 2024	trevorpreston
Unidentified	28 Mar 2024	trevorpreston

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User's notes

I'm not really sure what this is. A freshwater flatworm? @turb . Could it be some other kind of worm? It's not a leech, not segmented. Found on the underside of a rock and in the mud of a pond in Crace Grasslands.

7 comments

trevorpreston wrote:

28 Mar 2024

@turb Is this a flatworm? About 15mm long and definitely aquatic. Is there such a thing as freshwater flatworms?

trevorpreston wrote:

28 Mar 2024

possibly a nemertean?

turb wrote:

29 Mar 2024

The specimen looks very like Rhynchodemus sylvaticus, an introduced European species. Typically, the species has a brown "saddle" over the pharyngeal region, and this is seen in the small grey-coloured juvenile present in some of the photos. The species has been recorded in Australia previously. It is known as the snake-headed flatworm, as the anterior end is extensile as the flatworm actively senses the environment.

trevorpreston wrote:

29 Mar 2024

Thanks turb.
The juvenile seems to have the brown saddle. Does this change the likelihood of positive identification?

turb wrote:

29 Mar 2024

I have tried entering Rhynchodemus sylvaticus as a confirmed ID, but it is not accepted.

trevorpreston wrote:

29 Mar 2024

@turb I have created this species and suggested it. I am a bit perplexed as internet sources say this is a terrestrial planarian, but the ones I saw were definately submerged underwater under rocks and in mud. Does this sound right for this species?

turb wrote:

29 Mar 2024

Yes, and not just this species. Some land planarians are very tolerant of water, for example, Lenkunya munda is often found underwater in flooded areas. Other species strongly dislike too much water and will escape to higher ground.

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