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Bourkidinium granulatum
Bourkidinium granulatum, Morgan, 1975; Emendations: Nøhr-Hansen, 1993, p.48,50; Torricelli, 2000, p.261.
Holotype: Morgan, 1975, pl.2, figs.2a–c; Fensome et al., 1996, figs.1–3 — p.2141; Fauconnier and Masure, 2004, pl.11, fig.7.
Locus typicus: Great Australian Basin, Australia
Stratum typicum: Late Aptian-Albian
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Original description: [Morgan, 1975, p. 161]:
Description:
Chorate cyst is elongate ellipsoidal and bears long, hollow, distally flared processes arranged in two groups, one at the apical, and the other at the antapical, end. The number of processes is variable, but there are always more in the antapical group (9-15) than in the apical group (4-7). The processes are 23-30 µm long, 1.0-2.5 µm in diameter, cylindrical or slightly tapering towards the distal end, which is strongly flared, slightly recurved with serrate margins, and 5-6 µm in diameter.
The body, which is about 45 µm long and 25 µm in diameter, is densely granulate and lacks indications of a cingulum or tabulation.
The archeopyle is apical, type A, and all, or all but one or two, of the apical group of processes are on the free operculum.
Affinities:
This species is easily recognized by the unusual distribution of the processes. In both Tanyosphaeridium isocalamus (Deflandre and Cookson, 1955) and T. variecalamus Davey and Williams, 1966; that have ellipsoidal bodies, the processes are distributed more or less uniformly on the cyst, and their distal ends are not widely expanded distally as in Bourkidinium granulation.
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Ememded description:
Nohr-Hansen, 1993, p.48:
Description:
Chorate cysts with elongate ellipsoidal main body that bears long, hollow, distally flared processes arranged in two groups, one in the apical region and the other in the antapical region. The number of processes is variable but there are always more at the antapex than at the apex. The group at the antapex consist of 6-15 processes which, apart from the antapical processes, may include the postcingular and sulcal processes. The group at the apex consists of 4-10 processes including the apical, or the apical and precingular processes. The processes are cylindrical or slightly tapering towards the distal end which is strongly flared and slightly recurved with serrate margins.
The body is densely granulate and lacks indications of a cingulum or tabulation.
The archeopyle is apical (type tA).
The processes at apex are generally concentrated on the free, composite operculum but up to 6 processes may occur on the uppermost part of the precingular plate series leaving a wide equatorial zone devoided of processes.
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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.
Bourkedinium granulatum Morgan, 1975, emend Nöhr-Hansen, 1993, has long, hollow, distally flared processes arranged in two groups, one at the apical, one at the antapical pole. The apical processes number 4 to 7, the antapical processes are 9-15. The processes are 23-30 µm in length. Distally processes are flared, slightly recurved with serrate margins, and 5-6 µm in diameter. Body is densely granular. Nøhr-Hansen (1993) found that three specimens did not have precingular processes, the other nine had 1-6 precingular processes. The antapical group of processes is always the higher; there are 6-15 which apart from the antapical processes may include the postcingular and sulcal processes. The apical group is 4-10 processes including the apical, or the apical and precingular processes. The apical processes are generally concentrated on the operculum, but up to 6 processes may occur on the uppermost part of the precingular plate series leaving a wide equatorial zone devoid of processes.
Size: main body length 35-62 µm , width 20-29 µm.
Holotype: Morgan, 1975, pl.2, figs.2a–c; Fensome et al., 1996, figs.1–3 — p.2141; Fauconnier and Masure, 2004, pl.11, fig.7.
Locus typicus: Great Australian Basin, Australia
Stratum typicum: Late Aptian-Albian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Morgan, 1975, p. 161]:
Description:
Chorate cyst is elongate ellipsoidal and bears long, hollow, distally flared processes arranged in two groups, one at the apical, and the other at the antapical, end. The number of processes is variable, but there are always more in the antapical group (9-15) than in the apical group (4-7). The processes are 23-30 µm long, 1.0-2.5 µm in diameter, cylindrical or slightly tapering towards the distal end, which is strongly flared, slightly recurved with serrate margins, and 5-6 µm in diameter.
The body, which is about 45 µm long and 25 µm in diameter, is densely granulate and lacks indications of a cingulum or tabulation.
The archeopyle is apical, type A, and all, or all but one or two, of the apical group of processes are on the free operculum.
Affinities:
This species is easily recognized by the unusual distribution of the processes. In both Tanyosphaeridium isocalamus (Deflandre and Cookson, 1955) and T. variecalamus Davey and Williams, 1966; that have ellipsoidal bodies, the processes are distributed more or less uniformly on the cyst, and their distal ends are not widely expanded distally as in Bourkidinium granulation.
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Ememded description:
Nohr-Hansen, 1993, p.48:
Description:
Chorate cysts with elongate ellipsoidal main body that bears long, hollow, distally flared processes arranged in two groups, one in the apical region and the other in the antapical region. The number of processes is variable but there are always more at the antapex than at the apex. The group at the antapex consist of 6-15 processes which, apart from the antapical processes, may include the postcingular and sulcal processes. The group at the apex consists of 4-10 processes including the apical, or the apical and precingular processes. The processes are cylindrical or slightly tapering towards the distal end which is strongly flared and slightly recurved with serrate margins.
The body is densely granulate and lacks indications of a cingulum or tabulation.
The archeopyle is apical (type tA).
The processes at apex are generally concentrated on the free, composite operculum but up to 6 processes may occur on the uppermost part of the precingular plate series leaving a wide equatorial zone devoided of processes.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Bourkedinium granulatum Morgan, 1975, emend Nöhr-Hansen, 1993, has long, hollow, distally flared processes arranged in two groups, one at the apical, one at the antapical pole. The apical processes number 4 to 7, the antapical processes are 9-15. The processes are 23-30 µm in length. Distally processes are flared, slightly recurved with serrate margins, and 5-6 µm in diameter. Body is densely granular. Nøhr-Hansen (1993) found that three specimens did not have precingular processes, the other nine had 1-6 precingular processes. The antapical group of processes is always the higher; there are 6-15 which apart from the antapical processes may include the postcingular and sulcal processes. The apical group is 4-10 processes including the apical, or the apical and precingular processes. The apical processes are generally concentrated on the operculum, but up to 6 processes may occur on the uppermost part of the precingular plate series leaving a wide equatorial zone devoid of processes.
Size: main body length 35-62 µm , width 20-29 µm.