Land Planarian from Japan

Damp terrestrial arrowhead flatworm
April 29, 2010
I came across this flatworm under a moist slab of wood in my backyard garden. The flatworm has a head that resembles a fan at times and at other times an arrowhead. The tail anchored the flatworm to the moist wood, although this flatworm was pretty much curled and very mucusy. Along with this flatworm were orange winged beetles resembling ladybugs the size of peppercorn kernels and sow bugs under the wood slab. The dorsal side of the flatworm were 2 outer broad dark stripes (running from head to tail) with a thinner light dark stripe between and parallel to the 2 broad stripes. The underside was basically pale. There was only one flatworm not a community of them. For April it has been raining a bit more than usual, and the garden ground is a bit moist making it easier to pluck out unwanted baby weeds. I was just curious to see what community lived under this particular slab of wood.
My question is what type of flatworm is this?
Fukuoka City, Japan

Land Planarian

Hi Lucy,
Thank you for including the detailed information about the community you found under the slab of wood.  We do not have the necessary skills to identify what species of Planarian you have discovered.  It is very possible that it is a young Arrowhead Flatworm, Bipalium kewense, which can grow to ten inches in length.  The markings are consistent with that species.  The Texas Master Gardener website has a nice page on the Land Planarian.  The Featured Creatures website has a great page on the Land Planarian.

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