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Distatodinium apenninicum
Distatodinium apenninicum Brinkhuis et al., 1992, p.237-238, pl.1, figs.1-9; pl.8 (not pl.7 as given in Brinkhuis et al., 1992, p.236), figs.1-4.
Holotype: Brinkhuis et al., 1992, pl.1, figs.1-3.
Locus typicus: Contessa Quarry Section, Marche Basin, Italy
Age: Early Miocene.
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Distatodinium apenninicum Brinkhuis et al., 1992, has 15-18 intratabular, short, broad, tubular hollow processes. Distally the processes are closed and terminate in a complexly ramified, platform like structure that may be recurved about its margins, or may be modified with interconnections developed between adjacent processes to produce an incomplete ectophragm. Proximally the processes are flared and connected by low ridges. The 1p and 1ps processes may be united Paratabulation 4', 6", xc, 5"’, 1p, 1ps, 1"”. Surface smooth, scabrate to reticulate. Size: Central body length 45-58 µm, width 24-34 µm, process length 8-16 µm
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Original diagnosis: Brinkhuis et al., 1992, p.237
A species of Distatodinium that is characterized by the presence of 15 to 18 (including those on the operculum) intratabular, short, broad, tubular, hollow processes. Distally, the processes are closed and terminate in a complexly ramified, platform-like structure that may be recurved around its margin, or may be modified with interconnections developed between adjacent processes to produce an incomplete ectophragm. Proximally, the processes are flared and united by low ridges. Two apical processes may be united. A reflected gonyaulacean paratabulation of 4', 6", xc, 5''', 0-2p, 1'''' is inferred. The surface ornament is smooth to scabrate or lightly reticulate. The apical archeopyle, which is invariably evident with a detached operculum, reflects the loss of all the apical paraplates.
Dimensions: Central body length: 45-58 Ám (holotype, 52 Ám); width: 24-34 Ám (holotype, 29 Ám). Process length: 8-16 Ám (holotype, 12 Ám).
Affinities:
Brinkhuis et al., 1992, p.238: Distatodinium apenninicum differs from all other species of the genus by (1) the proximal ridges connecting adjacent processes, (2) the distal platform-like terminations of the processes, which (3) may connect adjacent processes.
The characteristic distal platform of the processes, which often produce trabeculae between neighboring processes, could be interpreted as the development of an ectophragm. Biffi and Manum (1988) observed and described this taxon (as 'genus et species indet.'), but did not determine its systematic position: they did make comparisons with the genus Eatonicysta Stover & Evitt 1978, on the strength of the presence of an "ectophragm supporting the processes". However, since such a feature was never observed in the specimens of the present study, we consider assignation of this species to Eatonicysta untenable.
Furthermore, species assigned to Eatonicysta have subspherical, rather than elongate, central bodies.
Holotype: Brinkhuis et al., 1992, pl.1, figs.1-3.
Locus typicus: Contessa Quarry Section, Marche Basin, Italy
Age: Early Miocene.
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Distatodinium apenninicum Brinkhuis et al., 1992, has 15-18 intratabular, short, broad, tubular hollow processes. Distally the processes are closed and terminate in a complexly ramified, platform like structure that may be recurved about its margins, or may be modified with interconnections developed between adjacent processes to produce an incomplete ectophragm. Proximally the processes are flared and connected by low ridges. The 1p and 1ps processes may be united Paratabulation 4', 6", xc, 5"’, 1p, 1ps, 1"”. Surface smooth, scabrate to reticulate. Size: Central body length 45-58 µm, width 24-34 µm, process length 8-16 µm
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Original diagnosis: Brinkhuis et al., 1992, p.237
A species of Distatodinium that is characterized by the presence of 15 to 18 (including those on the operculum) intratabular, short, broad, tubular, hollow processes. Distally, the processes are closed and terminate in a complexly ramified, platform-like structure that may be recurved around its margin, or may be modified with interconnections developed between adjacent processes to produce an incomplete ectophragm. Proximally, the processes are flared and united by low ridges. Two apical processes may be united. A reflected gonyaulacean paratabulation of 4', 6", xc, 5''', 0-2p, 1'''' is inferred. The surface ornament is smooth to scabrate or lightly reticulate. The apical archeopyle, which is invariably evident with a detached operculum, reflects the loss of all the apical paraplates.
Dimensions: Central body length: 45-58 Ám (holotype, 52 Ám); width: 24-34 Ám (holotype, 29 Ám). Process length: 8-16 Ám (holotype, 12 Ám).
Affinities:
Brinkhuis et al., 1992, p.238: Distatodinium apenninicum differs from all other species of the genus by (1) the proximal ridges connecting adjacent processes, (2) the distal platform-like terminations of the processes, which (3) may connect adjacent processes.
The characteristic distal platform of the processes, which often produce trabeculae between neighboring processes, could be interpreted as the development of an ectophragm. Biffi and Manum (1988) observed and described this taxon (as 'genus et species indet.'), but did not determine its systematic position: they did make comparisons with the genus Eatonicysta Stover & Evitt 1978, on the strength of the presence of an "ectophragm supporting the processes". However, since such a feature was never observed in the specimens of the present study, we consider assignation of this species to Eatonicysta untenable.
Furthermore, species assigned to Eatonicysta have subspherical, rather than elongate, central bodies.