Back
Apteodinium granulatum
Apteodinium granulatum, Eisenack, 1958; emend. Sarjeant, 1985; Emendations: Sarjeant, 1985; Lucas-Clark, 1987
Tax. sr. synonym of Apteodinium thelium Sarjeant, 1985, according to Jan du Chene et al., 1986. Sarjeant (pers. comm. in Lentin and Williams, 1989) retained Apteodinium thelium as a separate species.
Holotype: Eisenack, 1958, pl.23, fig.9; Sarjeant, 1985, pl.7, fig.1-2; Jan du Chene et al., 1986, pl.10, fig.1-2
Paratypes: Eisenack, 1958, according to Sarjeant, 1985; Sarjeant, 1985
Locus typicus: Borehole at Feld Heide, N Germany
Stratum typicum: Aptian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Eisenack, 1958, p. 386]: (Translation: Sarjeant, 1985, p. 80):
Diagnosis:
Shell oval to ovoidal, occasionally also somewhat pear-shaped, rarely (as result of compression?) rounded-rhomboidal in optical section. Girdle only rarely visible, scarcely indented, 4-5 µm broad; occasionally its position is marked in optical section by two marginal ridges, which cannot be distinguished in surface view.
Wall more or less strongly granulate, variable in thickness, thin to moderately thick, up to 4 µm.
Apical horn proportionally short, solid, pointed, varying in longitudinal section from almost equilaterally triangular to almost cylindrical, usually fairly sharply delineated. No antapical horn.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended descriptions:
Sarjeant, 1985, p. 79-83:
Diagnosis:
Proximate, cryptotabulate cysts; monocornucavate to epicavate or bicavate (though antapical cavation is never considerable) at the centre of which there arises a strong apical horn of triangular shape (sometimes approaching an equilateral triangle but usually somewhat more elongate and with 'shoulders' near its top), formed from the periphragm only. Within this larger horn is a broad, mamelon-like protuberance formed by the endophragm. Hypotract of comparable size to epitract but more rounded, sometimes almost hemispherical, the two wall layers sometimes separating slightly at the antapex.
Endophragm thick (up to 4 µm); periphragm quite thin and sometimes forming folds or ridges that may correspond with paraplate boundaries, though not sufficiently fully developed to enable determination of paratabulation.
Cingulum faintly marked by a slight indentation of the phragma, feebly laevorotatory; sulcus very poorly defined. Surface of phragma coarsely and densely granulate to almost tuberculate.
Archaeopyle single-plate precingular (type P), formed by loss of a portion of the dorsal surface corresponding to paraplate 3''; archaeopyle relatively small, asymmetrically subpentagonal.
Dimensions:
Holotype: overall length 77 µm, length of horn 12 µm, overall breadth 64 µm.
Range of dimensions: overall length 58-78 µm, breadth 50-64 µm. 6 specimens measured.
An extensive discussion on the morphological variation is given in Sarjeant, 1985.
-------------------------------------
Lucas-Clark, 1987, p. 172:
Description:
Intermediate to large, acavate, subspherical to subpolygonal cysts with apical horn.
Wall varies in an individual cyst from a single layer with scabrate or granular surface to a more complex structure involving an inner layer overlain by (1) a layer of spongy, cavernous material or irregular columns or short processes, which in turn is overlain or developed into (2) a discontinuous, perforate outer layer. Layers 1 and 2 may be considered to be periphragm (as in Benedek and Sarjeant's [1981] interpretation of Emslandia). Alternatively, layer 2 might be considered to be periphragm or ectophragm, or the whole wall might be considered to be a complex autophragm. Layers 1 and 2 may cover the entire cyst, but are more typically absent in the sulcal region, and in some specimens are absent from most of the cyst surface.
Paracingulum marked by low ridges and slight depression.
Parasulcus marked by relatively smooth area that interrupts the ornament, and by the ends of the paracingulum.
Outline in dorsal-ventral view varies from subspherical to polygonal. Outline in apical view circular with slight sulcal indentation.
Paratabulation partly expressed in some specimens by low ridges and depressions in the ornament, which may be visible only with scanning electron microscopy. Paratabulation as described for genus. Antapical paraplate strongly asymmetrical and positioned partly on the ventral side of the cyst. The IV/V/Y triple junction lies at the antapex and forms a slight antapical protrusion. Traces of growth bands may be discernible on pre- and postcingular paraplates.
Affinities:
A. granulatum differs from other species of Apteodinium in the degree of development of ornament or thickness of the spongy outer layer of wall (Text-Figure 7). Some species have smoother walls, e.g., A. maculatum, A. apiatum, and A.? albertii, while others have a thicker, more continuous spongy layer, e.g., A. spiridoides. Other species differ in having a longer or shorter apical
horn than A. granulatum, or in having a more spherical or more angular overall outline, or in being significantly larger or smaller.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Apteodinium granulatum Eisenack, 1958a, emend. Sarjeant, 1985a, emend. Lucas-Clark, 1987. From Lucas-Clark, 1987, p.172. Intermediate to large, acavate, subspherical to subpolygonal cysts with apical horn. Wall varies in an individual cyst from a single layer with scabrate or granular surface to a more complex structure involving an inner layer overlain by (1) a layer of spongy, cavernous material or irregular columns or short processes, which in turn is overlain or developed into (2) a discontinuous, perforate outer layer. Layers 1 and 2 may be considered to be periphragm. Alternatively layer 2 might be considered to be periphragm or ectophragm, or the whole wall might be considered to be a complex autophragm. Layers 1 and 2 may cover all the cyst or, more typically, be absent in the sulcal region and sometimes elsewhere. Cingulum marked by low ridges and slight depression. Paratabulation partly expressed in some specimens by low ridges and depressions in the ornament which may be visible only under the SEM. Antapical paraplate strongly asymmetrical and partly on the ventral side.
Size: length 58-78 µm, width 50-64 µm.
Tax. sr. synonym of Apteodinium thelium Sarjeant, 1985, according to Jan du Chene et al., 1986. Sarjeant (pers. comm. in Lentin and Williams, 1989) retained Apteodinium thelium as a separate species.
Holotype: Eisenack, 1958, pl.23, fig.9; Sarjeant, 1985, pl.7, fig.1-2; Jan du Chene et al., 1986, pl.10, fig.1-2
Paratypes: Eisenack, 1958, according to Sarjeant, 1985; Sarjeant, 1985
Locus typicus: Borehole at Feld Heide, N Germany
Stratum typicum: Aptian
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Eisenack, 1958, p. 386]: (Translation: Sarjeant, 1985, p. 80):
Diagnosis:
Shell oval to ovoidal, occasionally also somewhat pear-shaped, rarely (as result of compression?) rounded-rhomboidal in optical section. Girdle only rarely visible, scarcely indented, 4-5 µm broad; occasionally its position is marked in optical section by two marginal ridges, which cannot be distinguished in surface view.
Wall more or less strongly granulate, variable in thickness, thin to moderately thick, up to 4 µm.
Apical horn proportionally short, solid, pointed, varying in longitudinal section from almost equilaterally triangular to almost cylindrical, usually fairly sharply delineated. No antapical horn.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended descriptions:
Sarjeant, 1985, p. 79-83:
Diagnosis:
Proximate, cryptotabulate cysts; monocornucavate to epicavate or bicavate (though antapical cavation is never considerable) at the centre of which there arises a strong apical horn of triangular shape (sometimes approaching an equilateral triangle but usually somewhat more elongate and with 'shoulders' near its top), formed from the periphragm only. Within this larger horn is a broad, mamelon-like protuberance formed by the endophragm. Hypotract of comparable size to epitract but more rounded, sometimes almost hemispherical, the two wall layers sometimes separating slightly at the antapex.
Endophragm thick (up to 4 µm); periphragm quite thin and sometimes forming folds or ridges that may correspond with paraplate boundaries, though not sufficiently fully developed to enable determination of paratabulation.
Cingulum faintly marked by a slight indentation of the phragma, feebly laevorotatory; sulcus very poorly defined. Surface of phragma coarsely and densely granulate to almost tuberculate.
Archaeopyle single-plate precingular (type P), formed by loss of a portion of the dorsal surface corresponding to paraplate 3''; archaeopyle relatively small, asymmetrically subpentagonal.
Dimensions:
Holotype: overall length 77 µm, length of horn 12 µm, overall breadth 64 µm.
Range of dimensions: overall length 58-78 µm, breadth 50-64 µm. 6 specimens measured.
An extensive discussion on the morphological variation is given in Sarjeant, 1985.
-------------------------------------
Lucas-Clark, 1987, p. 172:
Description:
Intermediate to large, acavate, subspherical to subpolygonal cysts with apical horn.
Wall varies in an individual cyst from a single layer with scabrate or granular surface to a more complex structure involving an inner layer overlain by (1) a layer of spongy, cavernous material or irregular columns or short processes, which in turn is overlain or developed into (2) a discontinuous, perforate outer layer. Layers 1 and 2 may be considered to be periphragm (as in Benedek and Sarjeant's [1981] interpretation of Emslandia). Alternatively, layer 2 might be considered to be periphragm or ectophragm, or the whole wall might be considered to be a complex autophragm. Layers 1 and 2 may cover the entire cyst, but are more typically absent in the sulcal region, and in some specimens are absent from most of the cyst surface.
Paracingulum marked by low ridges and slight depression.
Parasulcus marked by relatively smooth area that interrupts the ornament, and by the ends of the paracingulum.
Outline in dorsal-ventral view varies from subspherical to polygonal. Outline in apical view circular with slight sulcal indentation.
Paratabulation partly expressed in some specimens by low ridges and depressions in the ornament, which may be visible only with scanning electron microscopy. Paratabulation as described for genus. Antapical paraplate strongly asymmetrical and positioned partly on the ventral side of the cyst. The IV/V/Y triple junction lies at the antapex and forms a slight antapical protrusion. Traces of growth bands may be discernible on pre- and postcingular paraplates.
Affinities:
A. granulatum differs from other species of Apteodinium in the degree of development of ornament or thickness of the spongy outer layer of wall (Text-Figure 7). Some species have smoother walls, e.g., A. maculatum, A. apiatum, and A.? albertii, while others have a thicker, more continuous spongy layer, e.g., A. spiridoides. Other species differ in having a longer or shorter apical
horn than A. granulatum, or in having a more spherical or more angular overall outline, or in being significantly larger or smaller.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Apteodinium granulatum Eisenack, 1958a, emend. Sarjeant, 1985a, emend. Lucas-Clark, 1987. From Lucas-Clark, 1987, p.172. Intermediate to large, acavate, subspherical to subpolygonal cysts with apical horn. Wall varies in an individual cyst from a single layer with scabrate or granular surface to a more complex structure involving an inner layer overlain by (1) a layer of spongy, cavernous material or irregular columns or short processes, which in turn is overlain or developed into (2) a discontinuous, perforate outer layer. Layers 1 and 2 may be considered to be periphragm. Alternatively layer 2 might be considered to be periphragm or ectophragm, or the whole wall might be considered to be a complex autophragm. Layers 1 and 2 may cover all the cyst or, more typically, be absent in the sulcal region and sometimes elsewhere. Cingulum marked by low ridges and slight depression. Paratabulation partly expressed in some specimens by low ridges and depressions in the ornament which may be visible only under the SEM. Antapical paraplate strongly asymmetrical and partly on the ventral side.
Size: length 58-78 µm, width 50-64 µm.