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Gonyaulacysta ehrenbergii
Gonyaulacysta ehrenbergii Gitmez, 1970
Now Cribroperidinium. Originally Gonyaulacysta, subsequently Millioudodinium, thirdly (and now) Cribroperidinium.
Holotype: Gitmez, 1970, pl.2, fig.8-9, text-fig.8
Locus typicus: Clay from the base of the Calcaires de Moulin Wibert, south side of Cap de La Creche, Boulonnais (CC 448), France
Stratum typicum: Early Kimmeridgian
Original diagnosis: Gitmez, 1970, p.252-253
Gonyaulacysta having an ovoidal theca of moderate wall thickness, with an apical horn. Tabulation: 4", 1a, 6"", 6c, 7""", 1p, 1pv, 1""""; sutures in form of moderately high, membraneous crests giving rise occasionally to short, blunt spines.
Cingulum narrow, helicoid, laevorotatory; sulcus of moderate breadth. Shell surface densely granular. Large precingular archaeopyle formed by loss of plate 3".
Dimensions: Holotype: overall length 70 µm, breadth 50 µm; horn length 8 µm; breadth of the cingulum 5-8 µm. Range (5 specimens measured): overall length 70-80 µm, breadth 50-65 µm; horn length 6-9 µm.
Original description: Gitmez, 1970, p.253
The shell is broadly ovoidal, giving rise to a strong apical horn; this is formed by three of the four apical plates (plates 1", 2" and 4"). Apical plates 1" and 4" are larger than the other two plates; 1" is elongate. The single anterior intercalary plate 1a is large and located between the apical plates 3", 4" and precingular plates 4", 5", 6". The precingular plates are generally large, plates 5" and 6"" being reduced to accommodate the intercalary plate 1a.
Seven postcingular plates are present: Plates 1""" and 2""" are reduced because of the large intercalary plate 1p; plates 6""" and 7""" are also reduced, since the large antapical plate 1"""" occupies a large area. The presence of posterior intercalary plate 1pv and the sulcal plates render the sulcus short and narrow.
Affinities:
Gitmez, 1970, p.253-254: Five specimens of this infrequent species were observed; all of them are well preserved. All records were from French assemblages--from Normandy, and the Boulonnais. The generic allocation of Gonyaulacysta ehrenbergii is questionable, in view of its possession of a seventh postcingular plate. The similarity in general morphology to a number of species of Gonyaulacysta resulted in its allocation to that genus. Since it possesses seven postcingular plates, there is a similarity between this species and the species of Cryptarchaeodinium; but the Cryptarchaeodinium species so far observed have a slightly different tabulation, with plate 2p and without the sulcal plates. One species of that genus, described for the first time in this paper, bears a blunt apical horn; but the apical horn of G. ehrenbergii is longer than the horn observed in Cryptarchaeodinium. G. ehrenbergii is twice the size of any described species of Cryptarchaeodinium.
With seven post-cingular plates, this new species is similar to G. fetchamensis and G. palla; but it differs in details of tabulation, general aspect and size. The general structure and thick wall render this species similar to G. scotti, which was recorded from Lower Kimmeridgian of Australia by Cookson and Eisenack (1958); since Cookson and Eisenack were unable to determine the tabulation of G. scotti, of which they give a very incomplete description, and since the holotype was not available for study, the relationships between this latter species and G. ehrenbergii can not be commented on.
Now Cribroperidinium. Originally Gonyaulacysta, subsequently Millioudodinium, thirdly (and now) Cribroperidinium.
Holotype: Gitmez, 1970, pl.2, fig.8-9, text-fig.8
Locus typicus: Clay from the base of the Calcaires de Moulin Wibert, south side of Cap de La Creche, Boulonnais (CC 448), France
Stratum typicum: Early Kimmeridgian
Original diagnosis: Gitmez, 1970, p.252-253
Gonyaulacysta having an ovoidal theca of moderate wall thickness, with an apical horn. Tabulation: 4", 1a, 6"", 6c, 7""", 1p, 1pv, 1""""; sutures in form of moderately high, membraneous crests giving rise occasionally to short, blunt spines.
Cingulum narrow, helicoid, laevorotatory; sulcus of moderate breadth. Shell surface densely granular. Large precingular archaeopyle formed by loss of plate 3".
Dimensions: Holotype: overall length 70 µm, breadth 50 µm; horn length 8 µm; breadth of the cingulum 5-8 µm. Range (5 specimens measured): overall length 70-80 µm, breadth 50-65 µm; horn length 6-9 µm.
Original description: Gitmez, 1970, p.253
The shell is broadly ovoidal, giving rise to a strong apical horn; this is formed by three of the four apical plates (plates 1", 2" and 4"). Apical plates 1" and 4" are larger than the other two plates; 1" is elongate. The single anterior intercalary plate 1a is large and located between the apical plates 3", 4" and precingular plates 4", 5", 6". The precingular plates are generally large, plates 5" and 6"" being reduced to accommodate the intercalary plate 1a.
Seven postcingular plates are present: Plates 1""" and 2""" are reduced because of the large intercalary plate 1p; plates 6""" and 7""" are also reduced, since the large antapical plate 1"""" occupies a large area. The presence of posterior intercalary plate 1pv and the sulcal plates render the sulcus short and narrow.
Affinities:
Gitmez, 1970, p.253-254: Five specimens of this infrequent species were observed; all of them are well preserved. All records were from French assemblages--from Normandy, and the Boulonnais. The generic allocation of Gonyaulacysta ehrenbergii is questionable, in view of its possession of a seventh postcingular plate. The similarity in general morphology to a number of species of Gonyaulacysta resulted in its allocation to that genus. Since it possesses seven postcingular plates, there is a similarity between this species and the species of Cryptarchaeodinium; but the Cryptarchaeodinium species so far observed have a slightly different tabulation, with plate 2p and without the sulcal plates. One species of that genus, described for the first time in this paper, bears a blunt apical horn; but the apical horn of G. ehrenbergii is longer than the horn observed in Cryptarchaeodinium. G. ehrenbergii is twice the size of any described species of Cryptarchaeodinium.
With seven post-cingular plates, this new species is similar to G. fetchamensis and G. palla; but it differs in details of tabulation, general aspect and size. The general structure and thick wall render this species similar to G. scotti, which was recorded from Lower Kimmeridgian of Australia by Cookson and Eisenack (1958); since Cookson and Eisenack were unable to determine the tabulation of G. scotti, of which they give a very incomplete description, and since the holotype was not available for study, the relationships between this latter species and G. ehrenbergii can not be commented on.