Fig 8. Exemplar for the character states of character 9.

A: state 0, only a slit visible from the outside, muscular valves protrude deep into the lumen (example from Euscorpius tergestrinus, lateral view, cLSM). B: state 1: deep V-shaped (horizontal section) trench; valves which are made up of several myofibers only protrude a little way into the lumen (example from Pseudodiaptomus pelagicus, dorsal view, cLSM) red cyan anaglyph, use goggles; C: state 2: shallow (almost flat) trench, most of the valve visible from outside (example from Nebalia herbstii, lateral view, cLSM). D: state 3: origin of ostial valves extruded; V-shaped trench of medium depth (example from Leucon nasica, ventrolateral view, 3D visualized from histological sections).