Figure 5. Summary of the results regarding Hypothesis 4 on trait frequency . The boxplots on the left graphically show proportion (from 0 to 1) of species with the selected traits across the three beach levels, following the same colour coding of figures 1-4 for beach level. Significant differences between pairs of levels after generalized linear models are marked with asterisks (***: p<0.001) (see Supplementary Table S7 for further details). The drawings on the right of the boxplots illustrate the traits in four genera; the silhouettes in the grey box show an overview of the whole animals for the same four genera. Capital letters: A.Parotoplana sp. B. Otoplana sp. C.Coelogynopora sp. D. Monocelis sp. Small letters:a. Typical anterior end of Parotoplana, showing cephalic area (black arrowhead) and brain capsule next to the statocyst (black asterisk) b. Same as ‘a’ for Otoplana. c.Typical anterior end of Coelogynopora, without sensory cephalic area (grey arrowhead) but with brain capsule next to the statocyst (black asterisk). d. Typical anterior end ofMonocelis, without cephalic sensory area (grey arrowhead) and without brain capsule (grey asterisk). e. Transverse section of Parotoplana, showing the flatness of the body and the ventral ciliary sole (black asterisk). f. Same as ‘e’ forOtoplana . g. Transverse section of Coelogynopora,cylindrical and without ciliary central sole. h. Same as ‘g’ for Monocelis . i. Transverse section of the collar-shaped pharynx of Paratoplana . j. Transverse section of the collar-shaped pharynx of Otoplana . k.Transverse section of the collar-shaped pharynx of Coelogynopora .l. Transverse section of the tubular pharynx ofMonocelis . m. Typical posterior end ofParotoplana showing the adhesive glands (black arrowhead) in a belt as well as along the body sides. n. Typical posterior end of Otoplana, showing the adhesive glands (black arrowhead) along the rear of the body. o. Same as ‘n’ for Coelogynopora .p. Same as ‘n’ for Monocelis.