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Barssidinium evangelinae
Barssidinium evangelinae, Lentin et al., 1994
Holotype: Lentin et al., 1994, pl. 2, fig. 8
Paratype: Lentin et al., 1994, pl. 2, fig. 7
Locus typicus: Amoco Imperial Heron H-73 well, Grand Banks, offshore E Canada
Stratum typicum: Late Miocene
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Original description: [Lentin et al., 1994, p. 578]:
Diagnosis:
A species of Barssidinium in which the processes are broad, hollow, distally open and aculeate. Process length about one seventh to one tenth of the length of the central body.
Description:
Shape: Cyst outline tends to be ovoidal to rounded pentagonal. Cyst weakly to strongly dorsoventrally compressed, ambitus subcircular, suboval, rounded pentagonal to peridinioid. Apex rounded; antapex rounded to weakly bilobate. Epicyst and hypocyst appear to be more or less equal in size.
Wall relationships: Usually acavate with autophragm only; rarely circumcavate, with periphragm and endophragm narrowly separated.
Wall features: Periphragm or autophragm smooth to densely granulate. Processes predominantly marginate and may be aligned, hollow, tubiform, open distally with expanded aculeate margins. Processes may have annular thickenings (or septa) (Pl. 2, fig. 3) and commonly have longitudinal striations (Pl. 3, fig. 4). Process length about one seventh to one tenth of the length of the central body and with a length-to-breadth ratio of between 2:1 and 5:1.
Mode of excystment: Usually involves the loss of a large hexa isodeltaform middorsal intercalary paraplate, presumably 2a, posteriorly extending almost to the equator of the cyst. The operculum is usually free, but may be adnate anteriorly. Rarely, accessory archeopyle sutures between paraplates adjacent to 2a appear to develop and a second intercalary paraplate may be dislodged. When two wall layers are observed, they appear fused on the operculum.
Paratabulation: Generally indicated by archeopyle only and presumed to be peridinialean; occasional alignment of processes suggests a paracingulum and possibly other parasutures. Parasulcus not identified.
Dimensions/Size:
Holotype: body length 99 µm, body width 99 µm, processes up to 11 µm.
Range: body length 60(80)99 µm (11 specimens), body width 60(76)99 µm (12 specimens), minimum length of processes 5(8)11 µm (5 specimens), maximum length of processes 6(11)14 µm (12 specimens).
Affinities: (p. 579):
Barssidinium wrennii, Barssidinium evangelineae, and Barssidinium graminosum are differentiated on the basis of the processes. Both B. wrennii and B. graminosum differ from B. evangelineae in having distally closed, furcate processes, in contrast to the distally open, aculeate processes of B. evangelineae. The length of the processes in B. wrennii and B. graminosum is different: in B. wrennii the process length is about one sixth to one eighth of the length of the central body; in B. graminosum, the process length is about one third to one fifth of the length of the central body. Although the process length in B. evangelineae is typically shorter than that in B. wrennii, there is some overlap.
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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.
Barssidinium evangelineae Lentin et al., 1994, has broad distally open, aculeate processes. Process length about 1/7 to 1/10th of length of central body.
Size: body length 60-99 µm, width 60-99 µm, minimum length of processes 5-11 µm, maximum length of processes 6-14 µm.
Holotype: Lentin et al., 1994, pl. 2, fig. 8
Paratype: Lentin et al., 1994, pl. 2, fig. 7
Locus typicus: Amoco Imperial Heron H-73 well, Grand Banks, offshore E Canada
Stratum typicum: Late Miocene
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Lentin et al., 1994, p. 578]:
Diagnosis:
A species of Barssidinium in which the processes are broad, hollow, distally open and aculeate. Process length about one seventh to one tenth of the length of the central body.
Description:
Shape: Cyst outline tends to be ovoidal to rounded pentagonal. Cyst weakly to strongly dorsoventrally compressed, ambitus subcircular, suboval, rounded pentagonal to peridinioid. Apex rounded; antapex rounded to weakly bilobate. Epicyst and hypocyst appear to be more or less equal in size.
Wall relationships: Usually acavate with autophragm only; rarely circumcavate, with periphragm and endophragm narrowly separated.
Wall features: Periphragm or autophragm smooth to densely granulate. Processes predominantly marginate and may be aligned, hollow, tubiform, open distally with expanded aculeate margins. Processes may have annular thickenings (or septa) (Pl. 2, fig. 3) and commonly have longitudinal striations (Pl. 3, fig. 4). Process length about one seventh to one tenth of the length of the central body and with a length-to-breadth ratio of between 2:1 and 5:1.
Mode of excystment: Usually involves the loss of a large hexa isodeltaform middorsal intercalary paraplate, presumably 2a, posteriorly extending almost to the equator of the cyst. The operculum is usually free, but may be adnate anteriorly. Rarely, accessory archeopyle sutures between paraplates adjacent to 2a appear to develop and a second intercalary paraplate may be dislodged. When two wall layers are observed, they appear fused on the operculum.
Paratabulation: Generally indicated by archeopyle only and presumed to be peridinialean; occasional alignment of processes suggests a paracingulum and possibly other parasutures. Parasulcus not identified.
Dimensions/Size:
Holotype: body length 99 µm, body width 99 µm, processes up to 11 µm.
Range: body length 60(80)99 µm (11 specimens), body width 60(76)99 µm (12 specimens), minimum length of processes 5(8)11 µm (5 specimens), maximum length of processes 6(11)14 µm (12 specimens).
Affinities: (p. 579):
Barssidinium wrennii, Barssidinium evangelineae, and Barssidinium graminosum are differentiated on the basis of the processes. Both B. wrennii and B. graminosum differ from B. evangelineae in having distally closed, furcate processes, in contrast to the distally open, aculeate processes of B. evangelineae. The length of the processes in B. wrennii and B. graminosum is different: in B. wrennii the process length is about one sixth to one eighth of the length of the central body; in B. graminosum, the process length is about one third to one fifth of the length of the central body. Although the process length in B. evangelineae is typically shorter than that in B. wrennii, there is some overlap.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Barssidinium evangelineae Lentin et al., 1994, has broad distally open, aculeate processes. Process length about 1/7 to 1/10th of length of central body.
Size: body length 60-99 µm, width 60-99 µm, minimum length of processes 5-11 µm, maximum length of processes 6-14 µm.