Fig. 2

Macrostomum lignano habitat, morphology, and life cycle. a The natural habitat of M. lignano in the upper intertidal zone of the Northern Adriatic. A systematic transect to study the distribution of Macrostomum species at Bocca d’Anfora, Italy, is shown. b Bright-field image and schematic representation of an adult worm (lightly squeezed to allow for better observation). Scale bar 100 µm. c Schematic visualization of the M. lignano life cycle