The ichnofossil Helicotaphrichnus commensalis in the Korytnica basiri (Middle Miocene; Holy Cross Mountains, Central Poland)

The ichnofossil Helicotaphrichnus commensalis is a morphologically distinct tube that is identical with modern tubes constructed by polychaetes in gastropod shells inhabited by hermit crabs. Its abundant occurrence in the Korytnica Clays (Middle Miocene; Holy Cross Mountains, Central Poland) extends both the stratigraphic range and the geographic distribution of this ichnospecies.