Back
Ambonosphaera bavarica
Ambonosphaera bavarica, Lund and Ecke, 1988
Holotype: Lund and Ecke 1988, pl.1, fig.2a-b, text-fig.3a
Locus typicus: The Orttenburg 1 well located in East Bavaria (TK 7445 Ortenburg, R91880, H 82484)
Statum typicum: (Middle) Oxfordian Voglarner Schichten (Ortennburg 1 at 256,1 m)
Age: ?late Mid Oxfordian.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Lund & Ecke, 1988]:
Diagnosis:
A species of small, cavate dinocysts with type 4A archeopyle and a usually poorly developed gonyaulacoid paratabulation. The shape of the thick-walled and rough sculptured endocyst is round to subsphaerical or subovoidal. The pericyst is smooth, thinner walled than the endocyst and is more or less well-attached to the epcystal sphere of the endocyst. On the hypocystal sphere the pericyst is loosly enveloping the endocyst forming a mostly multiply folded cava. A flagellar pore is present at the parasulcus between the ends of the paracingulum. The operculum is usually detached.
Description:
A species of the genus Ambonosphaera with a round to subsphaerical or ovoidal endocyst enclosed by a pericoel forming a well-developed cava at the hypocyst. The surface of the thick-walled endocysts shows a rough sculpture consisting of irregular shaped granules or verrucae with different diameters (max. 3 µm) which may be grouped together forming an irregular more or less vermiculate pseudoreticulum. Except for the fissures marking the surrounding precingular paraplates of the archeopyle and low depressions marking the paracingulum and the parasulcal area, there is no paratabulation indicated on the endocyst. In the sulcal area between the ends of the paracingulum the endocyst is perforated by bean-shaped, ellipsoidal or dumbbell-shaped flagellar pore. The pericyst has a considerably thinner wall than the endocyst forming a cava, which is more or less closely appressed to the epicystal region and loosely envelops the hypocystal region of the endocyst. The levorotatory paracingulum is indicated by a separation of the pericoel forming folds along the parasutures. Except for the paracingulum there are no or only indistinct indications (folds of the pericoel) of paraplates on the pericyst.
4A type archepyle is usually developed and the operculum is detached.
Dimensions:
Endocyst length: 42(46)50 µm
Endocyst width: 42(45)48 µm
Pericyst length: 52(56)62 µm
Pericyst width: 42(50)53 µm
Affinities/Remarks:
Ambonosphaera bavarica n.sp. is characterized by its rough sculptures endocyst, the flagellar ore and its pericoel forming a hypocystally extended cava. Especially by the last feature indicated by multiple folds of the hypocystal pericoel, this species is clearly distinguished from Ambonosphaera calloviana Fensome, 1979, which has a more closely appressed pericoel to the endocyst causing the more regularly shaped polygonal appearance. Mainly because of its well-developed 4A type archeopyle and the above mentioned epicystal attachment of th epericoel, A. bavarica was assigned to the genus Ambonosphaera Fensome, 1979, and not to Dinogymnium Cookson & Eisenack, emend. Mehrota & Sarjeant, 1984, which it may superficially resemble.
Holotype: Lund and Ecke 1988, pl.1, fig.2a-b, text-fig.3a
Locus typicus: The Orttenburg 1 well located in East Bavaria (TK 7445 Ortenburg, R91880, H 82484)
Statum typicum: (Middle) Oxfordian Voglarner Schichten (Ortennburg 1 at 256,1 m)
Age: ?late Mid Oxfordian.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Lund & Ecke, 1988]:
Diagnosis:
A species of small, cavate dinocysts with type 4A archeopyle and a usually poorly developed gonyaulacoid paratabulation. The shape of the thick-walled and rough sculptured endocyst is round to subsphaerical or subovoidal. The pericyst is smooth, thinner walled than the endocyst and is more or less well-attached to the epcystal sphere of the endocyst. On the hypocystal sphere the pericyst is loosly enveloping the endocyst forming a mostly multiply folded cava. A flagellar pore is present at the parasulcus between the ends of the paracingulum. The operculum is usually detached.
Description:
A species of the genus Ambonosphaera with a round to subsphaerical or ovoidal endocyst enclosed by a pericoel forming a well-developed cava at the hypocyst. The surface of the thick-walled endocysts shows a rough sculpture consisting of irregular shaped granules or verrucae with different diameters (max. 3 µm) which may be grouped together forming an irregular more or less vermiculate pseudoreticulum. Except for the fissures marking the surrounding precingular paraplates of the archeopyle and low depressions marking the paracingulum and the parasulcal area, there is no paratabulation indicated on the endocyst. In the sulcal area between the ends of the paracingulum the endocyst is perforated by bean-shaped, ellipsoidal or dumbbell-shaped flagellar pore. The pericyst has a considerably thinner wall than the endocyst forming a cava, which is more or less closely appressed to the epicystal region and loosely envelops the hypocystal region of the endocyst. The levorotatory paracingulum is indicated by a separation of the pericoel forming folds along the parasutures. Except for the paracingulum there are no or only indistinct indications (folds of the pericoel) of paraplates on the pericyst.
4A type archepyle is usually developed and the operculum is detached.
Dimensions:
Endocyst length: 42(46)50 µm
Endocyst width: 42(45)48 µm
Pericyst length: 52(56)62 µm
Pericyst width: 42(50)53 µm
Affinities/Remarks:
Ambonosphaera bavarica n.sp. is characterized by its rough sculptures endocyst, the flagellar ore and its pericoel forming a hypocystally extended cava. Especially by the last feature indicated by multiple folds of the hypocystal pericoel, this species is clearly distinguished from Ambonosphaera calloviana Fensome, 1979, which has a more closely appressed pericoel to the endocyst causing the more regularly shaped polygonal appearance. Mainly because of its well-developed 4A type archeopyle and the above mentioned epicystal attachment of th epericoel, A. bavarica was assigned to the genus Ambonosphaera Fensome, 1979, and not to Dinogymnium Cookson & Eisenack, emend. Mehrota & Sarjeant, 1984, which it may superficially resemble.