Artioposthia diemenensis, also known as Van Diemen's flatworm, is a species of land planarian in the tribe Caenoplanini. It has been found in southern Australia, including Tasmania.[1]
Artioposthia diemenensis is generally flat and broad, sloping inwards at its ends. When crawling, it can reach up to 70 mm in length and 6 mm in width. The backside is a sepia brown color with some darker stripes running down; the entire backside is covered in whitish speckles. The underside is a whitish color.[2]