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Impagidinium patulum
Impagidinium patulum (Wall, 1967) Stover and Evitt, 1978
Originally Leptodinium, subsequently (and now) Impagidinium.
Matsuoka, 1983, attributed the transfer of this species to lmpagidinium to Matsuoka, 1981.
Holotype: Wall, 1967, pl.15, figs.1,2
Locus typicus: Core A254/330, Yucatan basin (19¦ 35' N. 84¦ 51' W)
Stratum typicum: Middle Miocene-Holocene
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Impagidinium patulum (Wall, 1967) Stover and Evitt, 1978, has low, level sutural septa forming a tabulation that is characteristically reduced on the ventral surface. The test is rarely less than 40 µm. On the ventral surface, the sutures between 6" and as, and the posterior sutures of 1c and 6c are not developed. Sutures are also incompletely developed in the sulcus. Plates 1' and 4' are not separated by a suture but there is a reentrant angle. Size: test length 38-62 µm, width 34-55 µm, septa height 2.5-7 µm.
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Original diagnosis: Wall, 1967, p. 105: Leptodinium patulum
An ovoid species of Leptodinium ornamented with low, level sutural septa forming a plate-area pattern characteristically reduced on the ventral surface. Test rarely less than 40 µm.
Dimensions Test only 38-62 µm long, 34-55 µm, broad; septa 2.5 to 7 µm high. Over 50 specimens.
Original description: Wall, 1967, p. 105-106: Leptodinium patulum
The test appears weakly ovoid in lateral view and circular in polar view. Its surface Is smooth to weakly microgranular and bears a pronounced reflected tabulation defined by low, level sutural septa approximately equivalent to one-tenth of the test diameter in height. The formula is 4', 0a, 6'', 6g, 5''', 1p, 1''''. The test is divided into epithecal and hypothecal regions by a relatively narrow, weakly descending girdle; dorsally the girdle plate-areas are complete, but only the uppermost of the delimiting septa are present along two cingular plate-areas on the ventral surface adjacent to the furrow The epitheca lacks intercalary plate-areas. The apical series comprises two large pentagonal dorsal plate-areas (2' and 3') and a smaller, median ventral, compound plate-area representing 1' and 4'; here there is no complete division into two plate-areas but there is a significant re-entrant angle in the septum separating this areas from 3'. There are five discrete, subrectangular precingular plate-areas; 3'' forms a conspicuous dorsal archeopyle with its borders slightly within the septa. The sixth precingular platearea is not diflerentiated from the anterior sulcal platelet-area with which it forms a compound area in the mid-ventral equatorial region. The remainder of the furrow extends posteriorly and is almost entire; median and posterior platelet-areas are only indicated by rudimentary septal ingrowths. Similarly, the septum separating the relatively larger posterior intercalary plate-area from the furrow may be developed only partially. The remainder of the hypotheca comprises five large, subrectangular plate-areas and one quadrangular antapical (1'''').
Affinities:
Wall, 1967, p. 106: Leptodinium patulum
The characteristic tabulation of this species differentiates it clearly from any previously described.
Originally Leptodinium, subsequently (and now) Impagidinium.
Matsuoka, 1983, attributed the transfer of this species to lmpagidinium to Matsuoka, 1981.
Holotype: Wall, 1967, pl.15, figs.1,2
Locus typicus: Core A254/330, Yucatan basin (19¦ 35' N. 84¦ 51' W)
Stratum typicum: Middle Miocene-Holocene
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Impagidinium patulum (Wall, 1967) Stover and Evitt, 1978, has low, level sutural septa forming a tabulation that is characteristically reduced on the ventral surface. The test is rarely less than 40 µm. On the ventral surface, the sutures between 6" and as, and the posterior sutures of 1c and 6c are not developed. Sutures are also incompletely developed in the sulcus. Plates 1' and 4' are not separated by a suture but there is a reentrant angle. Size: test length 38-62 µm, width 34-55 µm, septa height 2.5-7 µm.
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Original diagnosis: Wall, 1967, p. 105: Leptodinium patulum
An ovoid species of Leptodinium ornamented with low, level sutural septa forming a plate-area pattern characteristically reduced on the ventral surface. Test rarely less than 40 µm.
Dimensions Test only 38-62 µm long, 34-55 µm, broad; septa 2.5 to 7 µm high. Over 50 specimens.
Original description: Wall, 1967, p. 105-106: Leptodinium patulum
The test appears weakly ovoid in lateral view and circular in polar view. Its surface Is smooth to weakly microgranular and bears a pronounced reflected tabulation defined by low, level sutural septa approximately equivalent to one-tenth of the test diameter in height. The formula is 4', 0a, 6'', 6g, 5''', 1p, 1''''. The test is divided into epithecal and hypothecal regions by a relatively narrow, weakly descending girdle; dorsally the girdle plate-areas are complete, but only the uppermost of the delimiting septa are present along two cingular plate-areas on the ventral surface adjacent to the furrow The epitheca lacks intercalary plate-areas. The apical series comprises two large pentagonal dorsal plate-areas (2' and 3') and a smaller, median ventral, compound plate-area representing 1' and 4'; here there is no complete division into two plate-areas but there is a significant re-entrant angle in the septum separating this areas from 3'. There are five discrete, subrectangular precingular plate-areas; 3'' forms a conspicuous dorsal archeopyle with its borders slightly within the septa. The sixth precingular platearea is not diflerentiated from the anterior sulcal platelet-area with which it forms a compound area in the mid-ventral equatorial region. The remainder of the furrow extends posteriorly and is almost entire; median and posterior platelet-areas are only indicated by rudimentary septal ingrowths. Similarly, the septum separating the relatively larger posterior intercalary plate-area from the furrow may be developed only partially. The remainder of the hypotheca comprises five large, subrectangular plate-areas and one quadrangular antapical (1'''').
Affinities:
Wall, 1967, p. 106: Leptodinium patulum
The characteristic tabulation of this species differentiates it clearly from any previously described.