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Chlamydophorella ectotabulata
Chlamydophorella ectotabulata, Smelror, 1989
Holotype: Smelror, 1989, pl.2, fig.1
Locus typicus: Cape Flora, Northbrook Island, Franz Josef land
Stratum typicum: Late Bathonian-Oxfordian
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Original description: [Smelror, 1989, p. 141-143]:
Diagnosis:
Holocavate dinoflagellate cysts, subsperhical to ovoidal in outline.
Endophragm with numerous, hollow tubiform processes of essentially uniform height. Ectophragm smooth, or more or less perforate, possessing gonyaulacoid paratabulation expressed as open lines (interruptions) on the ectophragm.
Archeopyle is apical, type (4A).
Description:
A species of Chlamydophorella, holocavate, usually subspherical to ovoidal in outline.
The endophragm has numerous (rarely less than 100 in optical section), relatively densely arranged processes. The processes are hollow and tube-like, distally baccinate and are of essentially uniform height within each specimen, but may vary from one specimen to another (although rarely exceeding 5 µm).
Except for the apical archeopyle and accessory archeopyle sutures exhibited by the anterior portion of the precingular paraplates, no evidence of paratabulation has been observed on the endocyst.
The ectophragm is smooth, or more or less perforate. On some specimens observed, the ectophragm seems developed as a continuous layer supported by the numerous processes, while on several specimens the ectophragm is interrupted along parasutures. This feature is very difficult to detect using light microscopy, however, using SEM the parasutures on the ectophragm become more evident. On less well preserved specimens the ectophragm is most often partly or completely torn off, and the evidences of paratabulation are destroyed.
The paratabulation pattern expressed on the ectophragm is typical gonyaulacoid. The archeopyle consists of the 4 apical paraplates. There are 6 precingular paraplates, the 3 (2") and 5 (4") being characteristically trapezoid-formed in shape and the 4 (3") and 6 (5") being pentagonal. The paracingulum, is formed as a descending spiral (laevorotatory), the offset being slightly greater than the paracingulum width (which is usually between 3-5 µm). The paracingulum is divided into 6 paraplates. The parasulcus is expressed as a relatively broad and straight to slightly sinuous depression, which extends for the most of the length of the cyst. Following Taylor"s terminology (see Evitt 1985) for gonyaulacoid sulcal patterns, this new species possesses a relatively large ai (as) paraplate), and relatively smaller fu (ras) and Iu (1""") paraplates. Separate Ii (rs) and Im (Is) paraplates have been observed only on a few specimens (Plate I, 2). Including the Iu (1"""), six postcingular paraplates are present. A posterior intercalary paraplate (X/lp) is present on the left side of the sulcus. Since the antapical (Y/1"""") contacts VI (5"""), the pattern is sexiform.
Dimensions:
Length (epicyst excluding apical paraplates) 48-64 µm, width 50-62 µm.
Holotype: Length 56 µm, width 64 µm.
Affinities: (p.143-144):
Chlamydophorella ectotabulata differs from Chlamydophorella raritubula Dodekova 1975 and Chlamydophorella wallala Cookson and Eisenack 1960 in being subspherical rather than elongate ellipsoidal to cylindrical in shape. Chlamydophorella raritubula possesses, in contrast to C. ectotabulata, relatively rare and large tube-like processes. On C. wallala the processes tend to be linearly arranged, especially in the equatorial region, while this feature appears not to be consistent on Chlamydophorella ectotabulata.
Holotype: Smelror, 1989, pl.2, fig.1
Locus typicus: Cape Flora, Northbrook Island, Franz Josef land
Stratum typicum: Late Bathonian-Oxfordian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Smelror, 1989, p. 141-143]:
Diagnosis:
Holocavate dinoflagellate cysts, subsperhical to ovoidal in outline.
Endophragm with numerous, hollow tubiform processes of essentially uniform height. Ectophragm smooth, or more or less perforate, possessing gonyaulacoid paratabulation expressed as open lines (interruptions) on the ectophragm.
Archeopyle is apical, type (4A).
Description:
A species of Chlamydophorella, holocavate, usually subspherical to ovoidal in outline.
The endophragm has numerous (rarely less than 100 in optical section), relatively densely arranged processes. The processes are hollow and tube-like, distally baccinate and are of essentially uniform height within each specimen, but may vary from one specimen to another (although rarely exceeding 5 µm).
Except for the apical archeopyle and accessory archeopyle sutures exhibited by the anterior portion of the precingular paraplates, no evidence of paratabulation has been observed on the endocyst.
The ectophragm is smooth, or more or less perforate. On some specimens observed, the ectophragm seems developed as a continuous layer supported by the numerous processes, while on several specimens the ectophragm is interrupted along parasutures. This feature is very difficult to detect using light microscopy, however, using SEM the parasutures on the ectophragm become more evident. On less well preserved specimens the ectophragm is most often partly or completely torn off, and the evidences of paratabulation are destroyed.
The paratabulation pattern expressed on the ectophragm is typical gonyaulacoid. The archeopyle consists of the 4 apical paraplates. There are 6 precingular paraplates, the 3 (2") and 5 (4") being characteristically trapezoid-formed in shape and the 4 (3") and 6 (5") being pentagonal. The paracingulum, is formed as a descending spiral (laevorotatory), the offset being slightly greater than the paracingulum width (which is usually between 3-5 µm). The paracingulum is divided into 6 paraplates. The parasulcus is expressed as a relatively broad and straight to slightly sinuous depression, which extends for the most of the length of the cyst. Following Taylor"s terminology (see Evitt 1985) for gonyaulacoid sulcal patterns, this new species possesses a relatively large ai (as) paraplate), and relatively smaller fu (ras) and Iu (1""") paraplates. Separate Ii (rs) and Im (Is) paraplates have been observed only on a few specimens (Plate I, 2). Including the Iu (1"""), six postcingular paraplates are present. A posterior intercalary paraplate (X/lp) is present on the left side of the sulcus. Since the antapical (Y/1"""") contacts VI (5"""), the pattern is sexiform.
Dimensions:
Length (epicyst excluding apical paraplates) 48-64 µm, width 50-62 µm.
Holotype: Length 56 µm, width 64 µm.
Affinities: (p.143-144):
Chlamydophorella ectotabulata differs from Chlamydophorella raritubula Dodekova 1975 and Chlamydophorella wallala Cookson and Eisenack 1960 in being subspherical rather than elongate ellipsoidal to cylindrical in shape. Chlamydophorella raritubula possesses, in contrast to C. ectotabulata, relatively rare and large tube-like processes. On C. wallala the processes tend to be linearly arranged, especially in the equatorial region, while this feature appears not to be consistent on Chlamydophorella ectotabulata.