Folder Morphometry contains geometric morphometric data. The shell shape was described by 11 landmarks and 56 semilandmarks. In total, the analysis included: 126 individuals of L. saxatilis (50-141 mm), 32 individuals of L. arcana (81-130 mm), 47 individuals of L. compressa (61-113 mm), 128 individuals of L. obtusata (55-167 mm) and 41 individuals of L. fabalis (50-147 mm).
- TPS.tps - the coordinates of landmarks and semilandmarks describing the shape of the shells of mollusks in .tps format.- curveslide.csv [semicolon separated] - semilandmark relative positions for import to geomorph package of R in specific geomorph format:= "before" [landmark id number] - id of landmark before the semilandmark;= "slide" [landmark id number] - semilandmark id;= "after" [landmark id number] - id of landmark after the semilandmark.- links.csv [semicolon separated] - positions of links between landmarks for graphical representation of shapes for import to geomorph package of R in specific geomorph format:= "start" [landmark id number] - landmark id at the link beginning;= "stop" [landmark id number] - landmark id at the link end.morphometry_metadata.csv - metadata on molluscs:= "ID" [text] - image id;= "Site" [text] - the name of the sampling site ("Saltstraumen", "Varangerfjord"); = "Level" [text] - level of the intertidal zone ("upper" or "lower"); = "Species" [text] - species of Littorina (L.arcana, L.saxatilis, L.compressa, L.obtusata, L.fabalis) ;= "Sex" [text] - sex ("f" - female; "m" - male);= "SpeciesGroup" - name of the species group ("'saxatilis'" - "saxatilis", "'obtusata'" -"obtusata");= "SpeciesSubpopulation" [text] - species name and subpopulation.- TPS_measurement_error.tps - the coordinates of landmarks and semilandmarks describing the shape of the shells of molluscs in .tps format. The dataset for calculation of measurement error related to digitization. measurement_error_metadata.csv- metadata on molluscs in TPS_measurement_error.tps (for variable description see morphometry_metadata.csv).