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Cometodinium whitei
Cometodinium? whitei, (Deflandre and Courteville, 1939), Stover and Evitt, 1978; emend. Monteil, 1991
Originally Hystrichosphaeridium, subsequently Baltisphaeridium, thirdly Impletosphaeridium, fourthly Comasphaeridium, fifthly (and now) Cometodinium?.
Stover and Evitt, 1978, considered this to be a provisionally accepted species of Cometodinium.
Holotype: Deflandre and Courteville, 1939, pl.3, fig.5 (lost according to Monteil, 1991)
Neotype: Monteil, 1991, pl.2, figs.1a-c; pl.3, fig.9 (designated by Monteil, 1991)
Stratigraphical and geographical distribution: appears that occurrence is presently restricted from the Coniacian of Marcoing, north France (DEFLANDRE & COURTEVILLE, 1939), the Senonian of Seine-Port, North France (this paper), the Senonian of Saint-Amand, North France (VALENSI, 1955) and the Early Campanian of the Central Alborz Mountains, Iran (WHEELER & SARJEANT, 1990).
Age: Senonian
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Emended description:
Monteil 1991, p. 444-445:
Diagnosis:
Chorate (skolochorate) cysts with subspherical body.
Sparse hair-like processes, thin and numerous, flexuous, typically grouped into short tufts Processes apparently nontabular, nonfibrous, cylindrical, distally closed, similar in size and shape Base undivided. Tip evexate.
Archeopyle apical, type (tA) with angular margin, often difficult to discern; operculum attached.
Paratabulation not expressed. Paracingulum and parasulcus not indicated.
Dimensions:
Holotype Paratype Neotype
Cyst diameter 85 µm 98 µm 84 µm
Central body diameter 60 µm 56 µm 64 µm
Length of processes up to 28 µm up to 28 µm up to 12,5 µm
Affinities:
C. whitei emend. differs from C. obscurum emend. in having sparse hair-like processes typically grouped into short tufts. The species C. whitei is compared with Exochosphaeridium arnace DAVEY & VERDIER, 1973, they have often been confused in the literature, e.g. 'H. whitei" in WILLAMS & BRIDEAUX (1975, pl. 24, fig. 7) and in MILLIOUD et al. (1975, pl 8, fig. 11; pl 3, fig. 16) belong undoubtedly to E. arnace.
To emphasize the differences between the two species, two specimens of E. arnace, one in a flint chip (Pl. 2, fig. 2), and another in a palynological strew slide (Pl. 2, fig. 3) are illustrated. C. whitei emend. differs from E. arnace in having an apical archeopyle rather than precingular and in lacking the "woolly" processes and the very distinctive diffuse zone surrounding the central body.
Remarks:
owing to its apical archeopyle, the species whitei is definitely attributed to the genus Cometodinium emend. The form illustrated, as C cf. whitei, by WHEELER & SARJEANT (1990, pl 7, fig. 1, 2) shows an apical archeopyle with a small attached operculum. This form corresponds in almost all respects with the specimen described by DEFLANDRE & COURTEVLLE (1939). Because the length of the processes appeared smaller than in the holotype of C. whitei, WHEELER & SARJEANT (1990) have merely compared it with, but not placed into, that species.
As DEFLANDRE & COURTEVLLE (1939) have apparently overestimated the length of the processes in both species, C. obscurum emend. and C. whitei emend., this form falls in the species diagnosis.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Cometodinium? whitei (Deflandre and Courteville, 1939) Stover and Evitt, 1978, emend. Monteil, 1991a. C. whitei differs from C.obscurum in having sparse hair-like processes typically grouped into short tufts.
Size: holotype, cyst diameter 85 µm, central body 60 µm, processes up to 28 µm.
Originally Hystrichosphaeridium, subsequently Baltisphaeridium, thirdly Impletosphaeridium, fourthly Comasphaeridium, fifthly (and now) Cometodinium?.
Stover and Evitt, 1978, considered this to be a provisionally accepted species of Cometodinium.
Holotype: Deflandre and Courteville, 1939, pl.3, fig.5 (lost according to Monteil, 1991)
Neotype: Monteil, 1991, pl.2, figs.1a-c; pl.3, fig.9 (designated by Monteil, 1991)
Stratigraphical and geographical distribution: appears that occurrence is presently restricted from the Coniacian of Marcoing, north France (DEFLANDRE & COURTEVILLE, 1939), the Senonian of Seine-Port, North France (this paper), the Senonian of Saint-Amand, North France (VALENSI, 1955) and the Early Campanian of the Central Alborz Mountains, Iran (WHEELER & SARJEANT, 1990).
Age: Senonian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Monteil 1991, p. 444-445:
Diagnosis:
Chorate (skolochorate) cysts with subspherical body.
Sparse hair-like processes, thin and numerous, flexuous, typically grouped into short tufts Processes apparently nontabular, nonfibrous, cylindrical, distally closed, similar in size and shape Base undivided. Tip evexate.
Archeopyle apical, type (tA) with angular margin, often difficult to discern; operculum attached.
Paratabulation not expressed. Paracingulum and parasulcus not indicated.
Dimensions:
Holotype Paratype Neotype
Cyst diameter 85 µm 98 µm 84 µm
Central body diameter 60 µm 56 µm 64 µm
Length of processes up to 28 µm up to 28 µm up to 12,5 µm
Affinities:
C. whitei emend. differs from C. obscurum emend. in having sparse hair-like processes typically grouped into short tufts. The species C. whitei is compared with Exochosphaeridium arnace DAVEY & VERDIER, 1973, they have often been confused in the literature, e.g. 'H. whitei" in WILLAMS & BRIDEAUX (1975, pl. 24, fig. 7) and in MILLIOUD et al. (1975, pl 8, fig. 11; pl 3, fig. 16) belong undoubtedly to E. arnace.
To emphasize the differences between the two species, two specimens of E. arnace, one in a flint chip (Pl. 2, fig. 2), and another in a palynological strew slide (Pl. 2, fig. 3) are illustrated. C. whitei emend. differs from E. arnace in having an apical archeopyle rather than precingular and in lacking the "woolly" processes and the very distinctive diffuse zone surrounding the central body.
Remarks:
owing to its apical archeopyle, the species whitei is definitely attributed to the genus Cometodinium emend. The form illustrated, as C cf. whitei, by WHEELER & SARJEANT (1990, pl 7, fig. 1, 2) shows an apical archeopyle with a small attached operculum. This form corresponds in almost all respects with the specimen described by DEFLANDRE & COURTEVLLE (1939). Because the length of the processes appeared smaller than in the holotype of C. whitei, WHEELER & SARJEANT (1990) have merely compared it with, but not placed into, that species.
As DEFLANDRE & COURTEVLLE (1939) have apparently overestimated the length of the processes in both species, C. obscurum emend. and C. whitei emend., this form falls in the species diagnosis.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Cometodinium? whitei (Deflandre and Courteville, 1939) Stover and Evitt, 1978, emend. Monteil, 1991a. C. whitei differs from C.obscurum in having sparse hair-like processes typically grouped into short tufts.
Size: holotype, cyst diameter 85 µm, central body 60 µm, processes up to 28 µm.