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Dissiliodinium baileyi
Dissiliodinium baileyi Feist-Burkhardt and Monteil, 2001, p.68,71, fig.10, nos.1-5; fig.20, no.1; table 2 (part).
Holotype: Feist-Burkhardt and Monteil, 2001, fig.10, nos.1-3; fig.20, no.1.
Age: Bajocian-Bathonian.
Original decription (Feist-Burkhardt and Monteil, 2001):
Derivation of name: In tribute to D. A. Bailey, who first reported this species from English Middle Jurassic sediments.
Stratigraphical and geographical occurrence: Bailey (1990): S England, late Bajocian; North Sea, Bajocian to Bathonian; this study: England, Early Bathonian, Zigzag Zone.
Description: Cyst proximate, subspherical. Autphragm thin, psilate to scabrate, ornamented by small to large verrucae. Verrucae are smooth, circular to oval in outline, regularly scattered, and spaced at relatively long distances. Archeopyle precingular, compound, variable, formed by the loss of up to 5 precingular paralates (1’’-5’’), opercular pieces free, adherent partially detached or adherent in place. Paratabulation indicated only by archeopyle when precingular paraplates are separated or displaced. Occasionally narrow lines drawn by the lack of ornamentation, faint grooves, or alignments of verrucae parallel to the plate boundaries can locally indicate the parasutures. Apical cap remains attached to the hypocyst by an isthmus consisting of the paraplate 6’’, as and, very often, 1’’. Paraplates of the apical cap are sometimes partially differentiated (i.e. dorsal anterior intercalary paraplates). The apical cap outline indicates the presence of four aical and two dorsal anterior intercalary paraplates (pl. 2, fig. 2, 5). Epicystal paratabulation gonyaulacacean, partial paratabulation formula: ?pr, 4’, 2a, 6’’, xs. Precingular paraplates stalked, except for 3’’. Paracingulum not indicated. Parasutural area indicated by a faint depression.
Dimensions: Holotype: 55 µm wide at paracingulum in lateral view (partly compressed specimen in glyerine jelly side); range in glycerine jelly slides: 55-75µm wide at paracingulum lateral view (partly compresses specimens).
Comparison: D. baileyi n. sp. differs from all other described Dissiliodinium species in its ornamentation, constituted of regularly scattered, small to large, smooth verrucae, which are spaced at relatively long distances (see Tab. 2).
Holotype: Feist-Burkhardt and Monteil, 2001, fig.10, nos.1-3; fig.20, no.1.
Age: Bajocian-Bathonian.
Original decription (Feist-Burkhardt and Monteil, 2001):
Derivation of name: In tribute to D. A. Bailey, who first reported this species from English Middle Jurassic sediments.
Stratigraphical and geographical occurrence: Bailey (1990): S England, late Bajocian; North Sea, Bajocian to Bathonian; this study: England, Early Bathonian, Zigzag Zone.
Description: Cyst proximate, subspherical. Autphragm thin, psilate to scabrate, ornamented by small to large verrucae. Verrucae are smooth, circular to oval in outline, regularly scattered, and spaced at relatively long distances. Archeopyle precingular, compound, variable, formed by the loss of up to 5 precingular paralates (1’’-5’’), opercular pieces free, adherent partially detached or adherent in place. Paratabulation indicated only by archeopyle when precingular paraplates are separated or displaced. Occasionally narrow lines drawn by the lack of ornamentation, faint grooves, or alignments of verrucae parallel to the plate boundaries can locally indicate the parasutures. Apical cap remains attached to the hypocyst by an isthmus consisting of the paraplate 6’’, as and, very often, 1’’. Paraplates of the apical cap are sometimes partially differentiated (i.e. dorsal anterior intercalary paraplates). The apical cap outline indicates the presence of four aical and two dorsal anterior intercalary paraplates (pl. 2, fig. 2, 5). Epicystal paratabulation gonyaulacacean, partial paratabulation formula: ?pr, 4’, 2a, 6’’, xs. Precingular paraplates stalked, except for 3’’. Paracingulum not indicated. Parasutural area indicated by a faint depression.
Dimensions: Holotype: 55 µm wide at paracingulum in lateral view (partly compressed specimen in glyerine jelly side); range in glycerine jelly slides: 55-75µm wide at paracingulum lateral view (partly compresses specimens).
Comparison: D. baileyi n. sp. differs from all other described Dissiliodinium species in its ornamentation, constituted of regularly scattered, small to large, smooth verrucae, which are spaced at relatively long distances (see Tab. 2).