◂Fig. 3 Historically described phenotypical variations and yet undiscovered deviations in the plate pattern of P. volzii. b–c, f, i, l–m Light microscopy, a, d–e, g–h, k scanning electron microscopy. a–f Newly identified deviations a–b plate 4′′ pentagonal in strains a GeoM*793; b GeoM*788; c plate 2a split (strain GeoK*024); d plates 2′′ and 3′′ fused (strain GeoM*866); e plates 1′′′ and 1′′′′ fused (strain GeoM*788); f plates 1a and 3′ fused (strain GeoM*788). g–m Historic infraspecific taxa; g P. guestrowiense forma lineatum (strain GeoM*866); h P. guestrowiense forma compressum (strain GeoM*866); i P. guestrowiense subvar. originale (strain GeoK*024); k P. volzii var. cinctiforme (strain GeoM*793); l P. volzii var. simplex (strain GeoM*789); m P. volzii forma complexum (strain GeoM*793). Abbreviations: n′: apical plate, n′′: precingular plate, n′′′: postcingular plate, n′′′′: antapical plate, na: anterior intercalary plate, nC: cingular plate, split or fused plates are indicated by asterisks. Scale bar= 10 µm. U A= 15 kV in Morphological and molecular variability of Peridinium volzii Lemmerm. (Peridiniaceae, Dinophyceae) and its relevance for infraspecific taxonomy

◂Fig. 3 Historically described phenotypical variations and yet undiscovered deviations in the plate pattern of P. volzii. b–c, f, i, l–m Light microscopy, a, d–e, g–h, k scanning electron microscopy. a–f Newly identified deviations a–b plate 4′′ pentagonal in strains a GeoM*793; b GeoM*788; c plate 2a split (strain GeoK*024); d plates 2′′ and 3′′ fused (strain GeoM*866); e plates 1′′′ and 1′′′′ fused (strain GeoM*788); f plates 1a and 3′ fused (strain GeoM*788). g–m Historic infraspecific taxa; g P. guestrowiense forma lineatum (strain GeoM*866); h P. guestrowiense forma compressum (strain GeoM*866); i P. guestrowiense subvar. originale (strain GeoK*024); k P. volzii var. cinctiforme (strain GeoM*793); l P. volzii var. simplex (strain GeoM*789); m P. volzii forma complexum (strain GeoM*793). Abbreviations: n′: apical plate, n′′: precingular plate, n′′′: postcingular plate, n′′′′: antapical plate, na: anterior intercalary plate, nC: cingular plate, split or fused plates are indicated by asterisks. Scale bar= 10 µm. U A= 15 kV