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Aptea polymorpha
Aptea polymorpha, Eisenack, 1958; Emend. Dörhöfer and Davies, 1980
Originally (and now) Aptea, subsequently Pseudoceratium.
By retaining Aptea, Quattrocchio and Sarjeant (1992, p.2–234) effectively retained Aptea polymorpha, the "type species", as a species of Aptea.
Taxonomic junior synonym: Aptea (now Pseudoceratium) eisenackii, according to Cookson and Eisenack (1974, p.74) — however, Below (1981a, p.7) retained Aptea eisenackii.
Holotype: Eisenack, 1958, pl.22, fig.5; Sarjeant, 1985, pl.7, fig.4
Locus typicus: Marne, Feld Heide, Holstein, N Germany
Stratum typicum: Early Cretaceous
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Original description: [Eisenack, 1958, p. 394]: (Translation: LPP):
Diagnosis:
Body (apparently naturally) flattened, in outline irregularly triangular with convex sides and indistinctly offset "horns", consisting of a rounded and dark inner capsule, which is ringed in by a more or less complete fringe. The surface is ornamented with an irregularly shaped network of low ridges, which forms a more or less fine, indistinct meshwork. In a radial direction, the ridges pass into the delicate, unequally thick edge, the margins of which rarely form a smooth line, but often appear zigzag and raveled. The 3 (also 4?) indistinctly developed horns can all but one be totally reduced.
Dimensions:
Length: 80-120 µm; Mean: 101 µm; 20 specimens measured.
Holotype: 114:80 µm.
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Emended description:
Dörhöfer and Davies, 1980, 34-36:
Description:
Autoblast subcircular to egg-shaped in outline, dorsoventrally flattened. Slight outward bulging occurs sometimes in the position of the three (occasionally four) horns which are marked by ornamental differentiation. These positions correspond to apical (left), antapical, and right postcingular horns. Either or both of the latter two horns may not be developed in all specimens, the postcingular horn being suppressed first. The axis connecting the apical and antapical horns is always shifted to the left, the cyst being always asymmetrical. The autoblast is rather thick-walled. Its surface is finely pitted to granulate. Often sutures are marked by relatively broad pandasutural zones, representing intercalary growth bands, characterized by striations perpendicular to the plate boundaries. Pandasutural areas are particularly distinct on the epitract along the archeopyle suture, less so on the hypotract. Tabulation formula: 4', 2a, 6", 5-6c, 6''', 1p, 1'''', ?3-6s.
Ornament on the cingulum, ventral plates 6c and 6" ', and the sulcus is reduced or absent. Plate 1p may be indistinct, particularly regarding its boundary with 1'''. The sulcal area is comprised of anterior, posterior, and left sulcal plates, and faint lines may indicate the presence of accessory plates. The position of a flagellar pore is indicated by a ring of low ridges to the left of the anterior sulcal plate.
The ornament is somewhat variable, comprising baculae, which are broadly based on the autoblast, tapered slightly and widened distally (Fig. 37A). The height of ornamental elements varies between 5 and 15 µm except over the three (or four) horns which are marked by longer processes reaching to about 30 µm at the apex and antapex. In these areas the ornament is appressed to the autoblast and is almost parallel with the autophragm. Distal fusion of process tips occurs frequently, especially on the horns.
The right postcingular horn position (a left postcingular horn is seldom indicated) is clearly related to the overall morphology of the cyst body. Its position can be expressed through the hypotractal divergence angle, which is measured between the axis connecting the apical and antapical horns and the point where the extended axis of the right postcingular horn intersects the cingulum on the dorsal side (Fig. 17). This divergence angle exhibits a linear relationship to the extension ratio (length/width: L/W). The longer the cyst body becomes, the smaller is the hypotractal divergence angle (Fig. 17). An extreme case is the disappearance of the postcingular horn once L/W is greater than 1.6; at the other extreme, forms with low extension ratios might exhibit indications of a left postcingular horn. The horn positions, however, become harder to determine with decreasing L/W as the horn bulges become indistinct and the outline almost circular. The presence of a fourth horn is restricted to these compact varieties.
The archeopyle is (4A21); its suture is zigzag in shape and asymmetrical, the left part being strongly deflected to the apex, the right part to the cingulum. Ventrally a sulcal notch is developed between plates 1' and 6", and another notch occurs where the 5" and 6" meet at the archeopyle suture. Dorsally the suture line dips down at the junctions of 2', 2", 3", and of 3', 3", 4". The presence of intercalary plates is responsible for the asymmetry of the archeopyle suture and of the autoblast. The sutures between the intercalary and the apical plates are very faint.
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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.
Aptea polymorpha Eisenack, 1958a, emend. Dörhöfer and Davies, 1980. From Eisenack, 1958, this has a flat autocyst, irregularly triangular in outline with convex sides and indistinctly affixed horns. The surface has an irregularly developed, low ledgework that forms a more or less fine-meshed, though indistinct honey-comb pattern. In an approximately radial direction, the ledges encroach upon the delicate and unequally wide membrane, the distal margins of which rarely form a smooth line, but seem frequently jagged and fimbriate. Of the three poorly developed horns, all except one may be more or less rudimentary. Dörhöfer and Davies (1980, p.34-36) gave a tabulation of 4', 2a, 6", 5-6c, 6"’, 1p, 1"”, 3-06s Length 80-120 µm.
Originally (and now) Aptea, subsequently Pseudoceratium.
By retaining Aptea, Quattrocchio and Sarjeant (1992, p.2–234) effectively retained Aptea polymorpha, the "type species", as a species of Aptea.
Taxonomic junior synonym: Aptea (now Pseudoceratium) eisenackii, according to Cookson and Eisenack (1974, p.74) — however, Below (1981a, p.7) retained Aptea eisenackii.
Holotype: Eisenack, 1958, pl.22, fig.5; Sarjeant, 1985, pl.7, fig.4
Locus typicus: Marne, Feld Heide, Holstein, N Germany
Stratum typicum: Early Cretaceous
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Original description: [Eisenack, 1958, p. 394]: (Translation: LPP):
Diagnosis:
Body (apparently naturally) flattened, in outline irregularly triangular with convex sides and indistinctly offset "horns", consisting of a rounded and dark inner capsule, which is ringed in by a more or less complete fringe. The surface is ornamented with an irregularly shaped network of low ridges, which forms a more or less fine, indistinct meshwork. In a radial direction, the ridges pass into the delicate, unequally thick edge, the margins of which rarely form a smooth line, but often appear zigzag and raveled. The 3 (also 4?) indistinctly developed horns can all but one be totally reduced.
Dimensions:
Length: 80-120 µm; Mean: 101 µm; 20 specimens measured.
Holotype: 114:80 µm.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Emended description:
Dörhöfer and Davies, 1980, 34-36:
Description:
Autoblast subcircular to egg-shaped in outline, dorsoventrally flattened. Slight outward bulging occurs sometimes in the position of the three (occasionally four) horns which are marked by ornamental differentiation. These positions correspond to apical (left), antapical, and right postcingular horns. Either or both of the latter two horns may not be developed in all specimens, the postcingular horn being suppressed first. The axis connecting the apical and antapical horns is always shifted to the left, the cyst being always asymmetrical. The autoblast is rather thick-walled. Its surface is finely pitted to granulate. Often sutures are marked by relatively broad pandasutural zones, representing intercalary growth bands, characterized by striations perpendicular to the plate boundaries. Pandasutural areas are particularly distinct on the epitract along the archeopyle suture, less so on the hypotract. Tabulation formula: 4', 2a, 6", 5-6c, 6''', 1p, 1'''', ?3-6s.
Ornament on the cingulum, ventral plates 6c and 6" ', and the sulcus is reduced or absent. Plate 1p may be indistinct, particularly regarding its boundary with 1'''. The sulcal area is comprised of anterior, posterior, and left sulcal plates, and faint lines may indicate the presence of accessory plates. The position of a flagellar pore is indicated by a ring of low ridges to the left of the anterior sulcal plate.
The ornament is somewhat variable, comprising baculae, which are broadly based on the autoblast, tapered slightly and widened distally (Fig. 37A). The height of ornamental elements varies between 5 and 15 µm except over the three (or four) horns which are marked by longer processes reaching to about 30 µm at the apex and antapex. In these areas the ornament is appressed to the autoblast and is almost parallel with the autophragm. Distal fusion of process tips occurs frequently, especially on the horns.
The right postcingular horn position (a left postcingular horn is seldom indicated) is clearly related to the overall morphology of the cyst body. Its position can be expressed through the hypotractal divergence angle, which is measured between the axis connecting the apical and antapical horns and the point where the extended axis of the right postcingular horn intersects the cingulum on the dorsal side (Fig. 17). This divergence angle exhibits a linear relationship to the extension ratio (length/width: L/W). The longer the cyst body becomes, the smaller is the hypotractal divergence angle (Fig. 17). An extreme case is the disappearance of the postcingular horn once L/W is greater than 1.6; at the other extreme, forms with low extension ratios might exhibit indications of a left postcingular horn. The horn positions, however, become harder to determine with decreasing L/W as the horn bulges become indistinct and the outline almost circular. The presence of a fourth horn is restricted to these compact varieties.
The archeopyle is (4A21); its suture is zigzag in shape and asymmetrical, the left part being strongly deflected to the apex, the right part to the cingulum. Ventrally a sulcal notch is developed between plates 1' and 6", and another notch occurs where the 5" and 6" meet at the archeopyle suture. Dorsally the suture line dips down at the junctions of 2', 2", 3", and of 3', 3", 4". The presence of intercalary plates is responsible for the asymmetry of the archeopyle suture and of the autoblast. The sutures between the intercalary and the apical plates are very faint.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Aptea polymorpha Eisenack, 1958a, emend. Dörhöfer and Davies, 1980. From Eisenack, 1958, this has a flat autocyst, irregularly triangular in outline with convex sides and indistinctly affixed horns. The surface has an irregularly developed, low ledgework that forms a more or less fine-meshed, though indistinct honey-comb pattern. In an approximately radial direction, the ledges encroach upon the delicate and unequally wide membrane, the distal margins of which rarely form a smooth line, but seem frequently jagged and fimbriate. Of the three poorly developed horns, all except one may be more or less rudimentary. Dörhöfer and Davies (1980, p.34-36) gave a tabulation of 4', 2a, 6", 5-6c, 6"’, 1p, 1"”, 3-06s Length 80-120 µm.