Land flatworm

Some posts take a long time to come out. This one in particular has been on the shelf for a long time. The reason? I wasn't sure of the identity of the animal for a while. I found it under a stone on the 29th of September 2012. A small, shiny white long thing, looking like a piece of root, but then it moved! What on earth was it? I picked it up and placed it on the white bowl, where its paleness didn't contrast as brutally with the background. A very stretchy animal, with no rings or setae: cannot be a nematode or an annelid... a flatworm? I got excited, a land flatworm, wow!, I didn't know we got these in gardens. Then I thought, wait a minute, isn't there an invasive land flatworm? I researched the topic. Yes, there are three species of native British land planarians...and at the turn of the XXI century 10 introduced species. After some inquiries it turned up mine was probably one of the native species, Microplana scharffi. Thank you to Christian Owen in iSpot who identified it for me.

The flatworm with its head up

Two freshwater flatworms

The garden barrel is one place where some invertebrate activity is guaranteed any time of the year. Snails graze algae in the winter and Water Slaters, Asellus aquaticus, munch the decayed leaves. There are predators too: flatworms. These innocent looking, slug-like animals, covered in sticky mucus slither on the surfaces of leaves looking for prey. Today I found two species, a small, dark one, probably Dugesia lugubris (top) and a large white one, Dendrocoelum lacteum (bottom). Both species shown here have a pair of simple eye spots, other species have more eyespots.

The LED lights of the hand held microscope reflect on the water surface and bring out the colour of the branching gastrovascular system of Dendrocoelum lacteum. The white band in the middle of the body is the evertible pharynx, on one end of which is the mouth. Small organisms, including Water Slaters, are often prey of flatworms, and are subdued with the mucus and wrappen on the flexible bodies of the flatworm.

More information

Richard Fitter & Richard Manuel 1986 Collins field guide to Freshwater life. 

Helen Mellanby 1975 Animal life in freshwater life. Chapman & Hall.