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Leptodinium patulum
Leptodinium patulum Wall, 1967
Now Impagidinium. Originally Leptodinium, subsequently (and now) Impagidinium.
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
Original diagnosis: Wall, 1967, p. 105
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 Ám.
Dimensions Test only 38-62 Ám long, 34-55 Ám, broad; septa 2.5 to 7 Ám high. Over 50 specimens.
Original description: Wall, 1967, p. 105-106
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: The characteristic tabulation of this species differentiates it clearly from any previously described.
Now Impagidinium. Originally Leptodinium, subsequently (and now) Impagidinium.
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
Original diagnosis: Wall, 1967, p. 105
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 Ám.
Dimensions Test only 38-62 Ám long, 34-55 Ám, broad; septa 2.5 to 7 Ám high. Over 50 specimens.
Original description: Wall, 1967, p. 105-106
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: The characteristic tabulation of this species differentiates it clearly from any previously described.